Logo Search packages:      
Sourcecode: postgresql-8.4 version File versions

dependency.c

/*-------------------------------------------------------------------------
 *
 * dependency.c
 *      Routines to support inter-object dependencies.
 *
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *      $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.89 2009/06/11 14:48:54 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/genam.h"
#include "access/heapam.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_cast.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_conversion.h"
#include "catalog/pg_conversion_fn.h"
#include "catalog/pg_database.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_foreign_data_wrapper.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_language.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_rewrite.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_ts_config.h"
#include "catalog/pg_ts_dict.h"
#include "catalog/pg_ts_parser.h"
#include "catalog/pg_ts_template.h"
#include "catalog/pg_type.h"
#include "catalog/pg_user_mapping.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/defrem.h"
#include "commands/proclang.h"
#include "commands/schemacmds.h"
#include "commands/tablespace.h"
#include "commands/trigger.h"
#include "commands/typecmds.h"
#include "foreign/foreign.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteRemove.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/tqual.h"


/*
 * Deletion processing requires additional state for each ObjectAddress that
 * it's planning to delete.  For simplicity and code-sharing we make the
 * ObjectAddresses code support arrays with or without this extra state.
 */
typedef struct
{
      int               flags;                  /* bitmask, see bit definitions below */
      ObjectAddress dependee;       /* object whose deletion forced this one */
} ObjectAddressExtra;

/* ObjectAddressExtra flag bits */
#define DEPFLAG_ORIGINAL      0x0001            /* an original deletion target */
#define DEPFLAG_NORMAL        0x0002            /* reached via normal dependency */
#define DEPFLAG_AUTO          0x0004            /* reached via auto dependency */
#define DEPFLAG_INTERNAL      0x0008            /* reached via internal dependency */


/* expansible list of ObjectAddresses */
struct ObjectAddresses
{
      ObjectAddress *refs;          /* => palloc'd array */
      ObjectAddressExtra *extras; /* => palloc'd array, or NULL if not used */
      int               numrefs;          /* current number of references */
      int               maxrefs;          /* current size of palloc'd array(s) */
};

/* typedef ObjectAddresses appears in dependency.h */

/* threaded list of ObjectAddresses, for recursion detection */
typedef struct ObjectAddressStack
{
      const ObjectAddress *object;  /* object being visited */
      int               flags;                  /* its current flag bits */
      struct ObjectAddressStack *next;    /* next outer stack level */
} ObjectAddressStack;

/* for find_expr_references_walker */
typedef struct
{
      ObjectAddresses *addrs;       /* addresses being accumulated */
      List     *rtables;            /* list of rangetables to resolve Vars */
} find_expr_references_context;

/*
 * This constant table maps ObjectClasses to the corresponding catalog OIDs.
 * See also getObjectClass().
 */
static const Oid object_classes[MAX_OCLASS] = {
      RelationRelationId,                 /* OCLASS_CLASS */
      ProcedureRelationId,          /* OCLASS_PROC */
      TypeRelationId,                     /* OCLASS_TYPE */
      CastRelationId,                     /* OCLASS_CAST */
      ConstraintRelationId,         /* OCLASS_CONSTRAINT */
      ConversionRelationId,         /* OCLASS_CONVERSION */
      AttrDefaultRelationId,        /* OCLASS_DEFAULT */
      LanguageRelationId,                 /* OCLASS_LANGUAGE */
      OperatorRelationId,                 /* OCLASS_OPERATOR */
      OperatorClassRelationId,      /* OCLASS_OPCLASS */
      OperatorFamilyRelationId,     /* OCLASS_OPFAMILY */
      AccessMethodOperatorRelationId,           /* OCLASS_AMOP */
      AccessMethodProcedureRelationId,    /* OCLASS_AMPROC */
      RewriteRelationId,                  /* OCLASS_REWRITE */
      TriggerRelationId,                  /* OCLASS_TRIGGER */
      NamespaceRelationId,          /* OCLASS_SCHEMA */
      TSParserRelationId,                 /* OCLASS_TSPARSER */
      TSDictionaryRelationId,       /* OCLASS_TSDICT */
      TSTemplateRelationId,         /* OCLASS_TSTEMPLATE */
      TSConfigRelationId,                 /* OCLASS_TSCONFIG */
      AuthIdRelationId,             /* OCLASS_ROLE */
      DatabaseRelationId,                 /* OCLASS_DATABASE */
      TableSpaceRelationId          /* OCLASS_TBLSPACE */
};


static void findDependentObjects(const ObjectAddress *object,
                               int flags,
                               ObjectAddressStack *stack,
                               ObjectAddresses *targetObjects,
                               const ObjectAddresses *pendingObjects,
                               Relation depRel);
static void reportDependentObjects(const ObjectAddresses *targetObjects,
                                 DropBehavior behavior,
                                 int msglevel,
                                 const ObjectAddress *origObject);
static void deleteOneObject(const ObjectAddress *object, Relation depRel);
static void doDeletion(const ObjectAddress *object);
static void AcquireDeletionLock(const ObjectAddress *object);
static void ReleaseDeletionLock(const ObjectAddress *object);
static bool find_expr_references_walker(Node *node,
                                          find_expr_references_context *context);
static void eliminate_duplicate_dependencies(ObjectAddresses *addrs);
static int  object_address_comparator(const void *a, const void *b);
static void add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
                           ObjectAddresses *addrs);
static void add_exact_object_address_extra(const ObjectAddress *object,
                                             const ObjectAddressExtra *extra,
                                             ObjectAddresses *addrs);
static bool object_address_present_add_flags(const ObjectAddress *object,
                                                 int flags,
                                                 ObjectAddresses *addrs);
static void getRelationDescription(StringInfo buffer, Oid relid);
static void getOpFamilyDescription(StringInfo buffer, Oid opfid);


/*
 * performDeletion: attempt to drop the specified object.  If CASCADE
 * behavior is specified, also drop any dependent objects (recursively).
 * If RESTRICT behavior is specified, error out if there are any dependent
 * objects, except for those that should be implicitly dropped anyway
 * according to the dependency type.
 *
 * This is the outer control routine for all forms of DROP that drop objects
 * that can participate in dependencies.  Note that the next two routines
 * are variants on the same theme; if you change anything here you'll likely
 * need to fix them too.
 */
void
performDeletion(const ObjectAddress *object,
                        DropBehavior behavior)
{
      Relation    depRel;
      ObjectAddresses *targetObjects;
      int               i;

      /*
       * We save some cycles by opening pg_depend just once and passing the
       * Relation pointer down to all the recursive deletion steps.
       */
      depRel = heap_open(DependRelationId, RowExclusiveLock);

      /*
       * Acquire deletion lock on the target object.  (Ideally the caller has
       * done this already, but many places are sloppy about it.)
       */
      AcquireDeletionLock(object);

      /*
       * Construct a list of objects to delete (ie, the given object plus
       * everything directly or indirectly dependent on it).
       */
      targetObjects = new_object_addresses();

      findDependentObjects(object,
                                     DEPFLAG_ORIGINAL,
                                     NULL,      /* empty stack */
                                     targetObjects,
                                     NULL,      /* no pendingObjects */
                                     depRel);

      /*
       * Check if deletion is allowed, and report about cascaded deletes.
       */
      reportDependentObjects(targetObjects,
                                       behavior,
                                       NOTICE,
                                       object);

      /*
       * Delete all the objects in the proper order.
       */
      for (i = 0; i < targetObjects->numrefs; i++)
      {
            ObjectAddress *thisobj = targetObjects->refs + i;

            deleteOneObject(thisobj, depRel);
      }

      /* And clean up */
      free_object_addresses(targetObjects);

      heap_close(depRel, RowExclusiveLock);
}

/*
 * performMultipleDeletions: Similar to performDeletion, but act on multiple
 * objects at once.
 *
 * The main difference from issuing multiple performDeletion calls is that the
 * list of objects that would be implicitly dropped, for each object to be
 * dropped, is the union of the implicit-object list for all objects.  This
 * makes each check be more relaxed.
 */
void
performMultipleDeletions(const ObjectAddresses *objects,
                                     DropBehavior behavior)
{
      Relation    depRel;
      ObjectAddresses *targetObjects;
      int               i;

      /* No work if no objects... */
      if (objects->numrefs <= 0)
            return;

      /*
       * We save some cycles by opening pg_depend just once and passing the
       * Relation pointer down to all the recursive deletion steps.
       */
      depRel = heap_open(DependRelationId, RowExclusiveLock);

      /*
       * Construct a list of objects to delete (ie, the given objects plus
       * everything directly or indirectly dependent on them).  Note that
       * because we pass the whole objects list as pendingObjects context, we
       * won't get a failure from trying to delete an object that is internally
       * dependent on another one in the list; we'll just skip that object and
       * delete it when we reach its owner.
       */
      targetObjects = new_object_addresses();

      for (i = 0; i < objects->numrefs; i++)
      {
            const ObjectAddress *thisobj = objects->refs + i;

            /*
             * Acquire deletion lock on each target object.  (Ideally the caller
             * has done this already, but many places are sloppy about it.)
             */
            AcquireDeletionLock(thisobj);

            findDependentObjects(thisobj,
                                           DEPFLAG_ORIGINAL,
                                           NULL,            /* empty stack */
                                           targetObjects,
                                           objects,
                                           depRel);
      }

      /*
       * Check if deletion is allowed, and report about cascaded deletes.
       *
       * If there's exactly one object being deleted, report it the same way as
       * in performDeletion(), else we have to be vaguer.
       */
      reportDependentObjects(targetObjects,
                                       behavior,
                                       NOTICE,
                                       (objects->numrefs == 1 ? objects->refs : NULL));

      /*
       * Delete all the objects in the proper order.
       */
      for (i = 0; i < targetObjects->numrefs; i++)
      {
            ObjectAddress *thisobj = targetObjects->refs + i;

            deleteOneObject(thisobj, depRel);
      }

      /* And clean up */
      free_object_addresses(targetObjects);

      heap_close(depRel, RowExclusiveLock);
}

/*
 * deleteWhatDependsOn: attempt to drop everything that depends on the
 * specified object, though not the object itself.    Behavior is always
 * CASCADE.
 *
 * This is currently used only to clean out the contents of a schema
 * (namespace): the passed object is a namespace.  We normally want this
 * to be done silently, so there's an option to suppress NOTICE messages.
 */
void
deleteWhatDependsOn(const ObjectAddress *object,
                              bool showNotices)
{
      Relation    depRel;
      ObjectAddresses *targetObjects;
      int               i;

      /*
       * We save some cycles by opening pg_depend just once and passing the
       * Relation pointer down to all the recursive deletion steps.
       */
      depRel = heap_open(DependRelationId, RowExclusiveLock);

      /*
       * Acquire deletion lock on the target object.  (Ideally the caller has
       * done this already, but many places are sloppy about it.)
       */
      AcquireDeletionLock(object);

      /*
       * Construct a list of objects to delete (ie, the given object plus
       * everything directly or indirectly dependent on it).
       */
      targetObjects = new_object_addresses();

      findDependentObjects(object,
                                     DEPFLAG_ORIGINAL,
                                     NULL,      /* empty stack */
                                     targetObjects,
                                     NULL,      /* no pendingObjects */
                                     depRel);

      /*
       * Check if deletion is allowed, and report about cascaded deletes.
       */
      reportDependentObjects(targetObjects,
                                       DROP_CASCADE,
                                       showNotices ? NOTICE : DEBUG2,
                                       object);

      /*
       * Delete all the objects in the proper order, except we skip the original
       * object.
       */
      for (i = 0; i < targetObjects->numrefs; i++)
      {
            ObjectAddress *thisobj = targetObjects->refs + i;
            ObjectAddressExtra *thisextra = targetObjects->extras + i;

            if (thisextra->flags & DEPFLAG_ORIGINAL)
                  continue;

            deleteOneObject(thisobj, depRel);
      }

      /* And clean up */
      free_object_addresses(targetObjects);

      heap_close(depRel, RowExclusiveLock);
}

/*
 * findDependentObjects - find all objects that depend on 'object'
 *
 * For every object that depends on the starting object, acquire a deletion
 * lock on the object, add it to targetObjects (if not already there),
 * and recursively find objects that depend on it.    An object's dependencies
 * will be placed into targetObjects before the object itself; this means
 * that the finished list's order represents a safe deletion order.
 *
 * The caller must already have a deletion lock on 'object' itself,
 * but must not have added it to targetObjects.  (Note: there are corner
 * cases where we won't add the object either, and will also release the
 * caller-taken lock.  This is a bit ugly, but the API is set up this way
 * to allow easy rechecking of an object's liveness after we lock it.  See
 * notes within the function.)
 *
 * When dropping a whole object (subId = 0), we find dependencies for
 * its sub-objects too.
 *
 *    object: the object to add to targetObjects and find dependencies on
 *    flags: flags to be ORed into the object's targetObjects entry
 *    stack: list of objects being visited in current recursion; topmost item
 *                is the object that we recursed from (NULL for external callers)
 *    targetObjects: list of objects that are scheduled to be deleted
 *    pendingObjects: list of other objects slated for destruction, but
 *                not necessarily in targetObjects yet (can be NULL if none)
 *    depRel: already opened pg_depend relation
 */
static void
findDependentObjects(const ObjectAddress *object,
                               int flags,
                               ObjectAddressStack *stack,
                               ObjectAddresses *targetObjects,
                               const ObjectAddresses *pendingObjects,
                               Relation depRel)
{
      ScanKeyData key[3];
      int               nkeys;
      SysScanDesc scan;
      HeapTuple   tup;
      ObjectAddress otherObject;
      ObjectAddressStack mystack;
      ObjectAddressExtra extra;
      ObjectAddressStack *stackptr;

      /*
       * If the target object is already being visited in an outer recursion
       * level, just report the current flags back to that level and exit. This
       * is needed to avoid infinite recursion in the face of circular
       * dependencies.
       *
       * The stack check alone would result in dependency loops being broken at
       * an arbitrary point, ie, the first member object of the loop to be
       * visited is the last one to be deleted.  This is obviously unworkable.
       * However, the check for internal dependency below guarantees that we
       * will not break a loop at an internal dependency: if we enter the loop
       * at an "owned" object we will switch and start at the "owning" object
       * instead.  We could probably hack something up to avoid breaking at an
       * auto dependency, too, if we had to.    However there are no known cases
       * where that would be necessary.
       */
      for (stackptr = stack; stackptr; stackptr = stackptr->next)
      {
            if (object->classId == stackptr->object->classId &&
                  object->objectId == stackptr->object->objectId)
            {
                  if (object->objectSubId == stackptr->object->objectSubId)
                  {
                        stackptr->flags |= flags;
                        return;
                  }

                  /*
                   * Could visit column with whole table already on stack; this is
                   * the same case noted in object_address_present_add_flags().
                   * (It's not clear this can really happen, but we might as well
                   * check.)
                   */
                  if (stackptr->object->objectSubId == 0)
                        return;
            }
      }

      /*
       * It's also possible that the target object has already been completely
       * processed and put into targetObjects.  If so, again we just add the
       * specified flags to its entry and return.
       *
       * (Note: in these early-exit cases we could release the caller-taken
       * lock, since the object is presumably now locked multiple times; but it
       * seems not worth the cycles.)
       */
      if (object_address_present_add_flags(object, flags, targetObjects))
            return;

      /*
       * The target object might be internally dependent on some other object
       * (its "owner").  If so, and if we aren't recursing from the owning
       * object, we have to transform this deletion request into a deletion
       * request of the owning object.  (We'll eventually recurse back to this
       * object, but the owning object has to be visited first so it will be
       * deleted after.)      The way to find out about this is to scan the
       * pg_depend entries that show what this object depends on.
       */
      ScanKeyInit(&key[0],
                        Anum_pg_depend_classid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->classId));
      ScanKeyInit(&key[1],
                        Anum_pg_depend_objid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->objectId));
      if (object->objectSubId != 0)
      {
            ScanKeyInit(&key[2],
                              Anum_pg_depend_objsubid,
                              BTEqualStrategyNumber, F_INT4EQ,
                              Int32GetDatum(object->objectSubId));
            nkeys = 3;
      }
      else
            nkeys = 2;

      scan = systable_beginscan(depRel, DependDependerIndexId, true,
                                            SnapshotNow, nkeys, key);

      while (HeapTupleIsValid(tup = systable_getnext(scan)))
      {
            Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);

            otherObject.classId = foundDep->refclassid;
            otherObject.objectId = foundDep->refobjid;
            otherObject.objectSubId = foundDep->refobjsubid;

            switch (foundDep->deptype)
            {
                  case DEPENDENCY_NORMAL:
                  case DEPENDENCY_AUTO:
                        /* no problem */
                        break;
                  case DEPENDENCY_INTERNAL:

                        /*
                         * This object is part of the internal implementation of
                         * another object.      We have three cases:
                         *
                         * 1. At the outermost recursion level, disallow the DROP. (We
                         * just ereport here, rather than proceeding, since no other
                         * dependencies are likely to be interesting.)  However, if
                         * the other object is listed in pendingObjects, just release
                         * the caller's lock and return; we'll eventually complete the
                         * DROP when we reach that entry in the pending list.
                         */
                        if (stack == NULL)
                        {
                              char     *otherObjDesc;

                              if (object_address_present(&otherObject, pendingObjects))
                              {
                                    systable_endscan(scan);
                                    /* need to release caller's lock; see notes below */
                                    ReleaseDeletionLock(object);
                                    return;
                              }
                              otherObjDesc = getObjectDescription(&otherObject);
                              ereport(ERROR,
                                          (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
                                           errmsg("cannot drop %s because %s requires it",
                                                      getObjectDescription(object),
                                                      otherObjDesc),
                                           errhint("You can drop %s instead.",
                                                       otherObjDesc)));
                        }

                        /*
                         * 2. When recursing from the other end of this dependency,
                         * it's okay to continue with the deletion. This holds when
                         * recursing from a whole object that includes the nominal
                         * other end as a component, too.
                         */
                        if (stack->object->classId == otherObject.classId &&
                              stack->object->objectId == otherObject.objectId &&
                              (stack->object->objectSubId == otherObject.objectSubId ||
                               stack->object->objectSubId == 0))
                              break;

                        /*
                         * 3. When recursing from anyplace else, transform this
                         * deletion request into a delete of the other object.
                         *
                         * First, release caller's lock on this object and get
                         * deletion lock on the other object.  (We must release
                         * caller's lock to avoid deadlock against a concurrent
                         * deletion of the other object.)
                         */
                        ReleaseDeletionLock(object);
                        AcquireDeletionLock(&otherObject);

                        /*
                         * The other object might have been deleted while we waited to
                         * lock it; if so, neither it nor the current object are
                         * interesting anymore.  We test this by checking the
                         * pg_depend entry (see notes below).
                         */
                        if (!systable_recheck_tuple(scan, tup))
                        {
                              systable_endscan(scan);
                              ReleaseDeletionLock(&otherObject);
                              return;
                        }

                        /*
                         * Okay, recurse to the other object instead of proceeding. We
                         * treat this exactly as if the original reference had linked
                         * to that object instead of this one; hence, pass through the
                         * same flags and stack.
                         */
                        findDependentObjects(&otherObject,
                                                       flags,
                                                       stack,
                                                       targetObjects,
                                                       pendingObjects,
                                                       depRel);
                        /* And we're done here. */
                        systable_endscan(scan);
                        return;
                  case DEPENDENCY_PIN:

                        /*
                         * Should not happen; PIN dependencies should have zeroes in
                         * the depender fields...
                         */
                        elog(ERROR, "incorrect use of PIN dependency with %s",
                               getObjectDescription(object));
                        break;
                  default:
                        elog(ERROR, "unrecognized dependency type '%c' for %s",
                               foundDep->deptype, getObjectDescription(object));
                        break;
            }
      }

      systable_endscan(scan);

      /*
       * Now recurse to any dependent objects.  We must visit them first since
       * they have to be deleted before the current object.
       */
      mystack.object = object;      /* set up a new stack level */
      mystack.flags = flags;
      mystack.next = stack;

      ScanKeyInit(&key[0],
                        Anum_pg_depend_refclassid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->classId));
      ScanKeyInit(&key[1],
                        Anum_pg_depend_refobjid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->objectId));
      if (object->objectSubId != 0)
      {
            ScanKeyInit(&key[2],
                              Anum_pg_depend_refobjsubid,
                              BTEqualStrategyNumber, F_INT4EQ,
                              Int32GetDatum(object->objectSubId));
            nkeys = 3;
      }
      else
            nkeys = 2;

      scan = systable_beginscan(depRel, DependReferenceIndexId, true,
                                            SnapshotNow, nkeys, key);

      while (HeapTupleIsValid(tup = systable_getnext(scan)))
      {
            Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
            int               subflags;

            otherObject.classId = foundDep->classid;
            otherObject.objectId = foundDep->objid;
            otherObject.objectSubId = foundDep->objsubid;

            /*
             * Must lock the dependent object before recursing to it.
             */
            AcquireDeletionLock(&otherObject);

            /*
             * The dependent object might have been deleted while we waited to
             * lock it; if so, we don't need to do anything more with it. We can
             * test this cheaply and independently of the object's type by seeing
             * if the pg_depend tuple we are looking at is still live. (If the
             * object got deleted, the tuple would have been deleted too.)
             */
            if (!systable_recheck_tuple(scan, tup))
            {
                  /* release the now-useless lock */
                  ReleaseDeletionLock(&otherObject);
                  /* and continue scanning for dependencies */
                  continue;
            }

            /* Recurse, passing flags indicating the dependency type */
            switch (foundDep->deptype)
            {
                  case DEPENDENCY_NORMAL:
                        subflags = DEPFLAG_NORMAL;
                        break;
                  case DEPENDENCY_AUTO:
                        subflags = DEPFLAG_AUTO;
                        break;
                  case DEPENDENCY_INTERNAL:
                        subflags = DEPFLAG_INTERNAL;
                        break;
                  case DEPENDENCY_PIN:

                        /*
                         * For a PIN dependency we just ereport immediately; there
                         * won't be any others to report.
                         */
                        ereport(ERROR,
                                    (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
                                     errmsg("cannot drop %s because it is required by the database system",
                                                getObjectDescription(object))));
                        subflags = 0;     /* keep compiler quiet */
                        break;
                  default:
                        elog(ERROR, "unrecognized dependency type '%c' for %s",
                               foundDep->deptype, getObjectDescription(object));
                        subflags = 0;     /* keep compiler quiet */
                        break;
            }

            findDependentObjects(&otherObject,
                                           subflags,
                                           &mystack,
                                           targetObjects,
                                           pendingObjects,
                                           depRel);
      }

      systable_endscan(scan);

      /*
       * Finally, we can add the target object to targetObjects.  Be careful to
       * include any flags that were passed back down to us from inner recursion
       * levels.
       */
      extra.flags = mystack.flags;
      if (stack)
            extra.dependee = *stack->object;
      else
            memset(&extra.dependee, 0, sizeof(extra.dependee));
      add_exact_object_address_extra(object, &extra, targetObjects);
}

/*
 * reportDependentObjects - report about dependencies, and fail if RESTRICT
 *
 * Tell the user about dependent objects that we are going to delete
 * (or would need to delete, but are prevented by RESTRICT mode);
 * then error out if there are any and it's not CASCADE mode.
 *
 *    targetObjects: list of objects that are scheduled to be deleted
 *    behavior: RESTRICT or CASCADE
 *    msglevel: elog level for non-error report messages
 *    origObject: base object of deletion, or NULL if not available
 *          (the latter case occurs in DROP OWNED)
 */
static void
reportDependentObjects(const ObjectAddresses *targetObjects,
                                 DropBehavior behavior,
                                 int msglevel,
                                 const ObjectAddress *origObject)
{
      bool        ok = true;
      StringInfoData clientdetail;
      StringInfoData logdetail;
      int               numReportedClient = 0;
      int               numNotReportedClient = 0;
      int               i;

      /*
       * If no error is to be thrown, and the msglevel is too low to be shown to
       * either client or server log, there's no need to do any of the work.
       *
       * Note: this code doesn't know all there is to be known about elog
       * levels, but it works for NOTICE and DEBUG2, which are the only values
       * msglevel can currently have.  We also assume we are running in a normal
       * operating environment.
       */
      if (behavior == DROP_CASCADE &&
            msglevel < client_min_messages &&
            (msglevel < log_min_messages || log_min_messages == LOG))
            return;

      /*
       * We limit the number of dependencies reported to the client to
       * MAX_REPORTED_DEPS, since client software may not deal well with
       * enormous error strings.    The server log always gets a full report.
       */
#define MAX_REPORTED_DEPS 100

      initStringInfo(&clientdetail);
      initStringInfo(&logdetail);

      /*
       * We process the list back to front (ie, in dependency order not deletion
       * order), since this makes for a more understandable display.
       */
      for (i = targetObjects->numrefs - 1; i >= 0; i--)
      {
            const ObjectAddress *obj = &targetObjects->refs[i];
            const ObjectAddressExtra *extra = &targetObjects->extras[i];
            char     *objDesc;

            /* Ignore the original deletion target(s) */
            if (extra->flags & DEPFLAG_ORIGINAL)
                  continue;

            objDesc = getObjectDescription(obj);

            /*
             * If, at any stage of the recursive search, we reached the object via
             * an AUTO or INTERNAL dependency, then it's okay to delete it even in
             * RESTRICT mode.
             */
            if (extra->flags & (DEPFLAG_AUTO | DEPFLAG_INTERNAL))
            {
                  /*
                   * auto-cascades are reported at DEBUG2, not msglevel.      We don't
                   * try to combine them with the regular message because the
                   * results are too confusing when client_min_messages and
                   * log_min_messages are different.
                   */
                  ereport(DEBUG2,
                              (errmsg("drop auto-cascades to %s",
                                          objDesc)));
            }
            else if (behavior == DROP_RESTRICT)
            {
                  char     *otherDesc = getObjectDescription(&extra->dependee);

                  if (numReportedClient < MAX_REPORTED_DEPS)
                  {
                        /* separate entries with a newline */
                        if (clientdetail.len != 0)
                              appendStringInfoChar(&clientdetail, '\n');
                        appendStringInfo(&clientdetail, _("%s depends on %s"),
                                                 objDesc, otherDesc);
                        numReportedClient++;
                  }
                  else
                        numNotReportedClient++;
                  /* separate entries with a newline */
                  if (logdetail.len != 0)
                        appendStringInfoChar(&logdetail, '\n');
                  appendStringInfo(&logdetail, _("%s depends on %s"),
                                           objDesc, otherDesc);
                  pfree(otherDesc);
                  ok = false;
            }
            else
            {
                  if (numReportedClient < MAX_REPORTED_DEPS)
                  {
                        /* separate entries with a newline */
                        if (clientdetail.len != 0)
                              appendStringInfoChar(&clientdetail, '\n');
                        appendStringInfo(&clientdetail, _("drop cascades to %s"),
                                                 objDesc);
                        numReportedClient++;
                  }
                  else
                        numNotReportedClient++;
                  /* separate entries with a newline */
                  if (logdetail.len != 0)
                        appendStringInfoChar(&logdetail, '\n');
                  appendStringInfo(&logdetail, _("drop cascades to %s"),
                                           objDesc);
            }

            pfree(objDesc);
      }

      if (numNotReportedClient > 0)
            appendStringInfo(&clientdetail, ngettext("\nand %d other object "
                                                                         "(see server log for list)",
                                                                         "\nand %d other objects "
                                                                         "(see server log for list)",
                                                                         numNotReportedClient),
                                     numNotReportedClient);

      if (!ok)
      {
            if (origObject)
                  ereport(ERROR,
                              (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
                          errmsg("cannot drop %s because other objects depend on it",
                                     getObjectDescription(origObject)),
                               errdetail("%s", clientdetail.data),
                               errdetail_log("%s", logdetail.data),
                               errhint("Use DROP ... CASCADE to drop the dependent objects too.")));
            else
                  ereport(ERROR,
                              (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
                               errmsg("cannot drop desired object(s) because other objects depend on them"),
                               errdetail("%s", clientdetail.data),
                               errdetail_log("%s", logdetail.data),
                               errhint("Use DROP ... CASCADE to drop the dependent objects too.")));
      }
      else if (numReportedClient > 1)
      {
            ereport(msglevel,
            /* translator: %d always has a value larger than 1 */
                        (errmsg_plural("drop cascades to %d other object",
                                             "drop cascades to %d other objects",
                                             numReportedClient + numNotReportedClient,
                                             numReportedClient + numNotReportedClient),
                         errdetail("%s", clientdetail.data),
                         errdetail_log("%s", logdetail.data)));
      }
      else if (numReportedClient == 1)
      {
            /* we just use the single item as-is */
            ereport(msglevel,
                        (errmsg_internal("%s", clientdetail.data)));
      }

      pfree(clientdetail.data);
      pfree(logdetail.data);
}

/*
 * deleteOneObject: delete a single object for performDeletion.
 *
 * depRel is the already-open pg_depend relation.
 */
static void
deleteOneObject(const ObjectAddress *object, Relation depRel)
{
      ScanKeyData key[3];
      int               nkeys;
      SysScanDesc scan;
      HeapTuple   tup;

      /*
       * First remove any pg_depend records that link from this object to
       * others.  (Any records linking to this object should be gone already.)
       *
       * When dropping a whole object (subId = 0), remove all pg_depend records
       * for its sub-objects too.
       */
      ScanKeyInit(&key[0],
                        Anum_pg_depend_classid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->classId));
      ScanKeyInit(&key[1],
                        Anum_pg_depend_objid,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(object->objectId));
      if (object->objectSubId != 0)
      {
            ScanKeyInit(&key[2],
                              Anum_pg_depend_objsubid,
                              BTEqualStrategyNumber, F_INT4EQ,
                              Int32GetDatum(object->objectSubId));
            nkeys = 3;
      }
      else
            nkeys = 2;

      scan = systable_beginscan(depRel, DependDependerIndexId, true,
                                            SnapshotNow, nkeys, key);

      while (HeapTupleIsValid(tup = systable_getnext(scan)))
      {
            simple_heap_delete(depRel, &tup->t_self);
      }

      systable_endscan(scan);

      /*
       * Delete shared dependency references related to this object.    Again, if
       * subId = 0, remove records for sub-objects too.
       */
      deleteSharedDependencyRecordsFor(object->classId, object->objectId,
                                                       object->objectSubId);

      /*
       * Now delete the object itself, in an object-type-dependent way.
       */
      doDeletion(object);

      /*
       * Delete any comments associated with this object.  (This is a convenient
       * place to do it instead of having every object type know to do it.)
       */
      DeleteComments(object->objectId, object->classId, object->objectSubId);

      /*
       * CommandCounterIncrement here to ensure that preceding changes are all
       * visible to the next deletion step.
       */
      CommandCounterIncrement();

      /*
       * And we're done!
       */
}

/*
 * doDeletion: actually delete a single object
 */
static void
doDeletion(const ObjectAddress *object)
{
      switch (getObjectClass(object))
      {
            case OCLASS_CLASS:
                  {
                        char        relKind = get_rel_relkind(object->objectId);

                        if (relKind == RELKIND_INDEX)
                        {
                              Assert(object->objectSubId == 0);
                              index_drop(object->objectId);
                        }
                        else
                        {
                              if (object->objectSubId != 0)
                                    RemoveAttributeById(object->objectId,
                                                                  object->objectSubId);
                              else
                                    heap_drop_with_catalog(object->objectId);
                        }
                        break;
                  }

            case OCLASS_PROC:
                  RemoveFunctionById(object->objectId);
                  break;

            case OCLASS_TYPE:
                  RemoveTypeById(object->objectId);
                  break;

            case OCLASS_CAST:
                  DropCastById(object->objectId);
                  break;

            case OCLASS_CONSTRAINT:
                  RemoveConstraintById(object->objectId);
                  break;

            case OCLASS_CONVERSION:
                  RemoveConversionById(object->objectId);
                  break;

            case OCLASS_DEFAULT:
                  RemoveAttrDefaultById(object->objectId);
                  break;

            case OCLASS_LANGUAGE:
                  DropProceduralLanguageById(object->objectId);
                  break;

            case OCLASS_OPERATOR:
                  RemoveOperatorById(object->objectId);
                  break;

            case OCLASS_OPCLASS:
                  RemoveOpClassById(object->objectId);
                  break;

            case OCLASS_OPFAMILY:
                  RemoveOpFamilyById(object->objectId);
                  break;

            case OCLASS_AMOP:
                  RemoveAmOpEntryById(object->objectId);
                  break;

            case OCLASS_AMPROC:
                  RemoveAmProcEntryById(object->objectId);
                  break;

            case OCLASS_REWRITE:
                  RemoveRewriteRuleById(object->objectId);
                  break;

            case OCLASS_TRIGGER:
                  RemoveTriggerById(object->objectId);
                  break;

            case OCLASS_SCHEMA:
                  RemoveSchemaById(object->objectId);
                  break;

            case OCLASS_TSPARSER:
                  RemoveTSParserById(object->objectId);
                  break;

            case OCLASS_TSDICT:
                  RemoveTSDictionaryById(object->objectId);
                  break;

            case OCLASS_TSTEMPLATE:
                  RemoveTSTemplateById(object->objectId);
                  break;

            case OCLASS_TSCONFIG:
                  RemoveTSConfigurationById(object->objectId);
                  break;

            case OCLASS_USER_MAPPING:
                  RemoveUserMappingById(object->objectId);
                  break;

            case OCLASS_FOREIGN_SERVER:
                  RemoveForeignServerById(object->objectId);
                  break;

            case OCLASS_FDW:
                  RemoveForeignDataWrapperById(object->objectId);
                  break;

                  /* OCLASS_ROLE, OCLASS_DATABASE, OCLASS_TBLSPACE not handled */

            default:
                  elog(ERROR, "unrecognized object class: %u",
                         object->classId);
      }
}

/*
 * AcquireDeletionLock - acquire a suitable lock for deleting an object
 *
 * We use LockRelation for relations, LockDatabaseObject for everything
 * else.  Note that dependency.c is not concerned with deleting any kind of
 * shared-across-databases object, so we have no need for LockSharedObject.
 */
static void
AcquireDeletionLock(const ObjectAddress *object)
{
      if (object->classId == RelationRelationId)
            LockRelationOid(object->objectId, AccessExclusiveLock);
      else
            /* assume we should lock the whole object not a sub-object */
            LockDatabaseObject(object->classId, object->objectId, 0,
                                       AccessExclusiveLock);
}

/*
 * ReleaseDeletionLock - release an object deletion lock
 */
static void
ReleaseDeletionLock(const ObjectAddress *object)
{
      if (object->classId == RelationRelationId)
            UnlockRelationOid(object->objectId, AccessExclusiveLock);
      else
            /* assume we should lock the whole object not a sub-object */
            UnlockDatabaseObject(object->classId, object->objectId, 0,
                                           AccessExclusiveLock);
}

/*
 * recordDependencyOnExpr - find expression dependencies
 *
 * This is used to find the dependencies of rules, constraint expressions,
 * etc.
 *
 * Given an expression or query in node-tree form, find all the objects
 * it refers to (tables, columns, operators, functions, etc).  Record
 * a dependency of the specified type from the given depender object
 * to each object mentioned in the expression.
 *
 * rtable is the rangetable to be used to interpret Vars with varlevelsup=0.
 * It can be NIL if no such variables are expected.
 */
void
recordDependencyOnExpr(const ObjectAddress *depender,
                                 Node *expr, List *rtable,
                                 DependencyType behavior)
{
      find_expr_references_context context;

      context.addrs = new_object_addresses();

      /* Set up interpretation for Vars at varlevelsup = 0 */
      context.rtables = list_make1(rtable);

      /* Scan the expression tree for referenceable objects */
      find_expr_references_walker(expr, &context);

      /* Remove any duplicates */
      eliminate_duplicate_dependencies(context.addrs);

      /* And record 'em */
      recordMultipleDependencies(depender,
                                             context.addrs->refs, context.addrs->numrefs,
                                             behavior);

      free_object_addresses(context.addrs);
}

/*
 * recordDependencyOnSingleRelExpr - find expression dependencies
 *
 * As above, but only one relation is expected to be referenced (with
 * varno = 1 and varlevelsup = 0).  Pass the relation OID instead of a
 * range table.  An additional frammish is that dependencies on that
 * relation (or its component columns) will be marked with 'self_behavior',
 * whereas 'behavior' is used for everything else.
 */
void
recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
                                                Node *expr, Oid relId,
                                                DependencyType behavior,
                                                DependencyType self_behavior)
{
      find_expr_references_context context;
      RangeTblEntry rte;

      context.addrs = new_object_addresses();

      /* We gin up a rather bogus rangetable list to handle Vars */
      MemSet(&rte, 0, sizeof(rte));
      rte.type = T_RangeTblEntry;
      rte.rtekind = RTE_RELATION;
      rte.relid = relId;

      context.rtables = list_make1(list_make1(&rte));

      /* Scan the expression tree for referenceable objects */
      find_expr_references_walker(expr, &context);

      /* Remove any duplicates */
      eliminate_duplicate_dependencies(context.addrs);

      /* Separate self-dependencies if necessary */
      if (behavior != self_behavior && context.addrs->numrefs > 0)
      {
            ObjectAddresses *self_addrs;
            ObjectAddress *outobj;
            int               oldref,
                              outrefs;

            self_addrs = new_object_addresses();

            outobj = context.addrs->refs;
            outrefs = 0;
            for (oldref = 0; oldref < context.addrs->numrefs; oldref++)
            {
                  ObjectAddress *thisobj = context.addrs->refs + oldref;

                  if (thisobj->classId == RelationRelationId &&
                        thisobj->objectId == relId)
                  {
                        /* Move this ref into self_addrs */
                        add_exact_object_address(thisobj, self_addrs);
                  }
                  else
                  {
                        /* Keep it in context.addrs */
                        *outobj = *thisobj;
                        outobj++;
                        outrefs++;
                  }
            }
            context.addrs->numrefs = outrefs;

            /* Record the self-dependencies */
            recordMultipleDependencies(depender,
                                                   self_addrs->refs, self_addrs->numrefs,
                                                   self_behavior);

            free_object_addresses(self_addrs);
      }

      /* Record the external dependencies */
      recordMultipleDependencies(depender,
                                             context.addrs->refs, context.addrs->numrefs,
                                             behavior);

      free_object_addresses(context.addrs);
}

/*
 * Recursively search an expression tree for object references.
 *
 * Note: we avoid creating references to columns of tables that participate
 * in an SQL JOIN construct, but are not actually used anywhere in the query.
 * To do so, we do not scan the joinaliasvars list of a join RTE while
 * scanning the query rangetable, but instead scan each individual entry
 * of the alias list when we find a reference to it.
 *
 * Note: in many cases we do not need to create dependencies on the datatypes
 * involved in an expression, because we'll have an indirect dependency via
 * some other object.  For instance Var nodes depend on a column which depends
 * on the datatype, and OpExpr nodes depend on the operator which depends on
 * the datatype.  However we do need a type dependency if there is no such
 * indirect dependency, as for example in Const and CoerceToDomain nodes.
 */
static bool
find_expr_references_walker(Node *node,
                                          find_expr_references_context *context)
{
      if (node == NULL)
            return false;
      if (IsA(node, Var))
      {
            Var            *var = (Var *) node;
            List     *rtable;
            RangeTblEntry *rte;

            /* Find matching rtable entry, or complain if not found */
            if (var->varlevelsup >= list_length(context->rtables))
                  elog(ERROR, "invalid varlevelsup %d", var->varlevelsup);
            rtable = (List *) list_nth(context->rtables, var->varlevelsup);
            if (var->varno <= 0 || var->varno > list_length(rtable))
                  elog(ERROR, "invalid varno %d", var->varno);
            rte = rt_fetch(var->varno, rtable);

            /*
             * A whole-row Var references no specific columns, so adds no new
             * dependency.
             */
            if (var->varattno == InvalidAttrNumber)
                  return false;
            if (rte->rtekind == RTE_RELATION)
            {
                  /* If it's a plain relation, reference this column */
                  add_object_address(OCLASS_CLASS, rte->relid, var->varattno,
                                             context->addrs);
            }
            else if (rte->rtekind == RTE_JOIN)
            {
                  /* Scan join output column to add references to join inputs */
                  List     *save_rtables;

                  /* We must make the context appropriate for join's level */
                  save_rtables = context->rtables;
                  context->rtables = list_copy_tail(context->rtables,
                                                                    var->varlevelsup);
                  if (var->varattno <= 0 ||
                        var->varattno > list_length(rte->joinaliasvars))
                        elog(ERROR, "invalid varattno %d", var->varattno);
                  find_expr_references_walker((Node *) list_nth(rte->joinaliasvars,
                                                                                      var->varattno - 1),
                                                            context);
                  list_free(context->rtables);
                  context->rtables = save_rtables;
            }
            return false;
      }
      else if (IsA(node, Const))
      {
            Const    *con = (Const *) node;
            Oid               objoid;

            /* A constant must depend on the constant's datatype */
            add_object_address(OCLASS_TYPE, con->consttype, 0,
                                       context->addrs);

            /*
             * If it's a regclass or similar literal referring to an existing
             * object, add a reference to that object.      (Currently, only the
             * regclass and regconfig cases have any likely use, but we may as
             * well handle all the OID-alias datatypes consistently.)
             */
            if (!con->constisnull)
            {
                  switch (con->consttype)
                  {
                        case REGPROCOID:
                        case REGPROCEDUREOID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(PROCOID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_PROC, objoid, 0,
                                                               context->addrs);
                              break;
                        case REGOPEROID:
                        case REGOPERATOROID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(OPEROID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_OPERATOR, objoid, 0,
                                                               context->addrs);
                              break;
                        case REGCLASSOID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(RELOID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_CLASS, objoid, 0,
                                                               context->addrs);
                              break;
                        case REGTYPEOID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(TYPEOID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_TYPE, objoid, 0,
                                                               context->addrs);
                              break;
                        case REGCONFIGOID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(TSCONFIGOID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_TSCONFIG, objoid, 0,
                                                               context->addrs);
                              break;
                        case REGDICTIONARYOID:
                              objoid = DatumGetObjectId(con->constvalue);
                              if (SearchSysCacheExists(TSDICTOID,
                                                                   ObjectIdGetDatum(objoid),
                                                                   0, 0, 0))
                                    add_object_address(OCLASS_TSDICT, objoid, 0,
                                                               context->addrs);
                              break;
                  }
            }
            return false;
      }
      else if (IsA(node, Param))
      {
            Param    *param = (Param *) node;

            /* A parameter must depend on the parameter's datatype */
            add_object_address(OCLASS_TYPE, param->paramtype, 0,
                                       context->addrs);
      }
      else if (IsA(node, FuncExpr))
      {
            FuncExpr   *funcexpr = (FuncExpr *) node;

            add_object_address(OCLASS_PROC, funcexpr->funcid, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, OpExpr))
      {
            OpExpr         *opexpr = (OpExpr *) node;

            add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, DistinctExpr))
      {
            DistinctExpr *distinctexpr = (DistinctExpr *) node;

            add_object_address(OCLASS_OPERATOR, distinctexpr->opno, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, ScalarArrayOpExpr))
      {
            ScalarArrayOpExpr *opexpr = (ScalarArrayOpExpr *) node;

            add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, NullIfExpr))
      {
            NullIfExpr *nullifexpr = (NullIfExpr *) node;

            add_object_address(OCLASS_OPERATOR, nullifexpr->opno, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, Aggref))
      {
            Aggref         *aggref = (Aggref *) node;

            add_object_address(OCLASS_PROC, aggref->aggfnoid, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, WindowFunc))
      {
            WindowFunc *wfunc = (WindowFunc *) node;

            add_object_address(OCLASS_PROC, wfunc->winfnoid, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, SubPlan))
      {
            /* Extra work needed here if we ever need this case */
            elog(ERROR, "already-planned subqueries not supported");
      }
      else if (IsA(node, RelabelType))
      {
            RelabelType *relab = (RelabelType *) node;

            /* since there is no function dependency, need to depend on type */
            add_object_address(OCLASS_TYPE, relab->resulttype, 0,
                                       context->addrs);
      }
      else if (IsA(node, CoerceViaIO))
      {
            CoerceViaIO *iocoerce = (CoerceViaIO *) node;

            /* since there is no exposed function, need to depend on type */
            add_object_address(OCLASS_TYPE, iocoerce->resulttype, 0,
                                       context->addrs);
      }
      else if (IsA(node, ArrayCoerceExpr))
      {
            ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;

            if (OidIsValid(acoerce->elemfuncid))
                  add_object_address(OCLASS_PROC, acoerce->elemfuncid, 0,
                                             context->addrs);
            add_object_address(OCLASS_TYPE, acoerce->resulttype, 0,
                                       context->addrs);
            /* fall through to examine arguments */
      }
      else if (IsA(node, ConvertRowtypeExpr))
      {
            ConvertRowtypeExpr *cvt = (ConvertRowtypeExpr *) node;

            /* since there is no function dependency, need to depend on type */
            add_object_address(OCLASS_TYPE, cvt->resulttype, 0,
                                       context->addrs);
      }
      else if (IsA(node, RowExpr))
      {
            RowExpr    *rowexpr = (RowExpr *) node;

            add_object_address(OCLASS_TYPE, rowexpr->row_typeid, 0,
                                       context->addrs);
      }
      else if (IsA(node, RowCompareExpr))
      {
            RowCompareExpr *rcexpr = (RowCompareExpr *) node;
            ListCell   *l;

            foreach(l, rcexpr->opnos)
            {
                  add_object_address(OCLASS_OPERATOR, lfirst_oid(l), 0,
                                             context->addrs);
            }
            foreach(l, rcexpr->opfamilies)
            {
                  add_object_address(OCLASS_OPFAMILY, lfirst_oid(l), 0,
                                             context->addrs);
            }
            /* fall through to examine arguments */
      }
      else if (IsA(node, CoerceToDomain))
      {
            CoerceToDomain *cd = (CoerceToDomain *) node;

            add_object_address(OCLASS_TYPE, cd->resulttype, 0,
                                       context->addrs);
      }
      else if (IsA(node, SortGroupClause))
      {
            SortGroupClause *sgc = (SortGroupClause *) node;

            add_object_address(OCLASS_OPERATOR, sgc->eqop, 0,
                                       context->addrs);
            if (OidIsValid(sgc->sortop))
                  add_object_address(OCLASS_OPERATOR, sgc->sortop, 0,
                                             context->addrs);
            return false;
      }
      else if (IsA(node, Query))
      {
            /* Recurse into RTE subquery or not-yet-planned sublink subquery */
            Query    *query = (Query *) node;
            ListCell   *rtable;
            bool        result;

            /*
             * Add whole-relation refs for each plain relation mentioned in the
             * subquery's rtable, as well as datatype refs for any datatypes used
             * as a RECORD function's output.  (Note: query_tree_walker takes care
             * of recursing into RTE_FUNCTION RTEs, subqueries, etc, so no need to
             * do that here.  But keep it from looking at join alias lists.)
             */
            foreach(rtable, query->rtable)
            {
                  RangeTblEntry *rte = (RangeTblEntry *) lfirst(rtable);
                  ListCell   *ct;

                  switch (rte->rtekind)
                  {
                        case RTE_RELATION:
                              add_object_address(OCLASS_CLASS, rte->relid, 0,
                                                         context->addrs);
                              break;
                        case RTE_FUNCTION:
                              foreach(ct, rte->funccoltypes)
                              {
                                    add_object_address(OCLASS_TYPE, lfirst_oid(ct), 0,
                                                               context->addrs);
                              }
                              break;
                        default:
                              break;
                  }
            }

            /* query_tree_walker ignores ORDER BY etc, but we need those opers */
            find_expr_references_walker((Node *) query->sortClause, context);
            find_expr_references_walker((Node *) query->groupClause, context);
            find_expr_references_walker((Node *) query->windowClause, context);
            find_expr_references_walker((Node *) query->distinctClause, context);

            /* Examine substructure of query */
            context->rtables = lcons(query->rtable, context->rtables);
            result = query_tree_walker(query,
                                                   find_expr_references_walker,
                                                   (void *) context,
                                                   QTW_IGNORE_JOINALIASES);
            context->rtables = list_delete_first(context->rtables);
            return result;
      }
      else if (IsA(node, SetOperationStmt))
      {
            SetOperationStmt *setop = (SetOperationStmt *) node;

            /* we need to look at the groupClauses for operator references */
            find_expr_references_walker((Node *) setop->groupClauses, context);
            /* fall through to examine child nodes */
      }

      return expression_tree_walker(node, find_expr_references_walker,
                                                  (void *) context);
}

/*
 * Given an array of dependency references, eliminate any duplicates.
 */
static void
eliminate_duplicate_dependencies(ObjectAddresses *addrs)
{
      ObjectAddress *priorobj;
      int               oldref,
                        newrefs;

      /*
       * We can't sort if the array has "extra" data, because there's no way to
       * keep it in sync.  Fortunately that combination of features is not
       * needed.
       */
      Assert(!addrs->extras);

      if (addrs->numrefs <= 1)
            return;                             /* nothing to do */

      /* Sort the refs so that duplicates are adjacent */
      qsort((void *) addrs->refs, addrs->numrefs, sizeof(ObjectAddress),
              object_address_comparator);

      /* Remove dups */
      priorobj = addrs->refs;
      newrefs = 1;
      for (oldref = 1; oldref < addrs->numrefs; oldref++)
      {
            ObjectAddress *thisobj = addrs->refs + oldref;

            if (priorobj->classId == thisobj->classId &&
                  priorobj->objectId == thisobj->objectId)
            {
                  if (priorobj->objectSubId == thisobj->objectSubId)
                        continue;         /* identical, so drop thisobj */

                  /*
                   * If we have a whole-object reference and a reference to a part
                   * of the same object, we don't need the whole-object reference
                   * (for example, we don't need to reference both table foo and
                   * column foo.bar).  The whole-object reference will always appear
                   * first in the sorted list.
                   */
                  if (priorobj->objectSubId == 0)
                  {
                        /* replace whole ref with partial */
                        priorobj->objectSubId = thisobj->objectSubId;
                        continue;
                  }
            }
            /* Not identical, so add thisobj to output set */
            priorobj++;
            *priorobj = *thisobj;
            newrefs++;
      }

      addrs->numrefs = newrefs;
}

/*
 * qsort comparator for ObjectAddress items
 */
static int
object_address_comparator(const void *a, const void *b)
{
      const ObjectAddress *obja = (const ObjectAddress *) a;
      const ObjectAddress *objb = (const ObjectAddress *) b;

      if (obja->classId < objb->classId)
            return -1;
      if (obja->classId > objb->classId)
            return 1;
      if (obja->objectId < objb->objectId)
            return -1;
      if (obja->objectId > objb->objectId)
            return 1;

      /*
       * We sort the subId as an unsigned int so that 0 will come first. See
       * logic in eliminate_duplicate_dependencies.
       */
      if ((unsigned int) obja->objectSubId < (unsigned int) objb->objectSubId)
            return -1;
      if ((unsigned int) obja->objectSubId > (unsigned int) objb->objectSubId)
            return 1;
      return 0;
}

/*
 * Routines for handling an expansible array of ObjectAddress items.
 *
 * new_object_addresses: create a new ObjectAddresses array.
 */
ObjectAddresses *
new_object_addresses(void)
{
      ObjectAddresses *addrs;

      addrs = palloc(sizeof(ObjectAddresses));

      addrs->numrefs = 0;
      addrs->maxrefs = 32;
      addrs->refs = (ObjectAddress *)
            palloc(addrs->maxrefs * sizeof(ObjectAddress));
      addrs->extras = NULL;         /* until/unless needed */

      return addrs;
}

/*
 * Add an entry to an ObjectAddresses array.
 *
 * It is convenient to specify the class by ObjectClass rather than directly
 * by catalog OID.
 */
static void
add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
                           ObjectAddresses *addrs)
{
      ObjectAddress *item;

      /* enlarge array if needed */
      if (addrs->numrefs >= addrs->maxrefs)
      {
            addrs->maxrefs *= 2;
            addrs->refs = (ObjectAddress *)
                  repalloc(addrs->refs, addrs->maxrefs * sizeof(ObjectAddress));
            Assert(!addrs->extras);
      }
      /* record this item */
      item = addrs->refs + addrs->numrefs;
      item->classId = object_classes[oclass];
      item->objectId = objectId;
      item->objectSubId = subId;
      addrs->numrefs++;
}

/*
 * Add an entry to an ObjectAddresses array.
 *
 * As above, but specify entry exactly.
 */
void
add_exact_object_address(const ObjectAddress *object,
                                     ObjectAddresses *addrs)
{
      ObjectAddress *item;

      /* enlarge array if needed */
      if (addrs->numrefs >= addrs->maxrefs)
      {
            addrs->maxrefs *= 2;
            addrs->refs = (ObjectAddress *)
                  repalloc(addrs->refs, addrs->maxrefs * sizeof(ObjectAddress));
            Assert(!addrs->extras);
      }
      /* record this item */
      item = addrs->refs + addrs->numrefs;
      *item = *object;
      addrs->numrefs++;
}

/*
 * Add an entry to an ObjectAddresses array.
 *
 * As above, but specify entry exactly and provide some "extra" data too.
 */
static void
add_exact_object_address_extra(const ObjectAddress *object,
                                             const ObjectAddressExtra *extra,
                                             ObjectAddresses *addrs)
{
      ObjectAddress *item;
      ObjectAddressExtra *itemextra;

      /* allocate extra space if first time */
      if (!addrs->extras)
            addrs->extras = (ObjectAddressExtra *)
                  palloc(addrs->maxrefs * sizeof(ObjectAddressExtra));

      /* enlarge array if needed */
      if (addrs->numrefs >= addrs->maxrefs)
      {
            addrs->maxrefs *= 2;
            addrs->refs = (ObjectAddress *)
                  repalloc(addrs->refs, addrs->maxrefs * sizeof(ObjectAddress));
            addrs->extras = (ObjectAddressExtra *)
                  repalloc(addrs->extras, addrs->maxrefs * sizeof(ObjectAddressExtra));
      }
      /* record this item */
      item = addrs->refs + addrs->numrefs;
      *item = *object;
      itemextra = addrs->extras + addrs->numrefs;
      *itemextra = *extra;
      addrs->numrefs++;
}

/*
 * Test whether an object is present in an ObjectAddresses array.
 *
 * We return "true" if object is a subobject of something in the array, too.
 */
bool
object_address_present(const ObjectAddress *object,
                                 const ObjectAddresses *addrs)
{
      int               i;

      for (i = addrs->numrefs - 1; i >= 0; i--)
      {
            const ObjectAddress *thisobj = addrs->refs + i;

            if (object->classId == thisobj->classId &&
                  object->objectId == thisobj->objectId)
            {
                  if (object->objectSubId == thisobj->objectSubId ||
                        thisobj->objectSubId == 0)
                        return true;
            }
      }

      return false;
}

/*
 * As above, except that if the object is present then also OR the given
 * flags into its associated extra data (which must exist).
 */
static bool
object_address_present_add_flags(const ObjectAddress *object,
                                                 int flags,
                                                 ObjectAddresses *addrs)
{
      int               i;

      for (i = addrs->numrefs - 1; i >= 0; i--)
      {
            ObjectAddress *thisobj = addrs->refs + i;

            if (object->classId == thisobj->classId &&
                  object->objectId == thisobj->objectId)
            {
                  if (object->objectSubId == thisobj->objectSubId)
                  {
                        ObjectAddressExtra *thisextra = addrs->extras + i;

                        thisextra->flags |= flags;
                        return true;
                  }
                  if (thisobj->objectSubId == 0)
                  {
                        /*
                         * We get here if we find a need to delete a column after
                         * having already decided to drop its whole table.    Obviously
                         * we no longer need to drop the column.  But don't plaster
                         * its flags on the table.
                         */
                        return true;
                  }
            }
      }

      return false;
}

/*
 * Record multiple dependencies from an ObjectAddresses array, after first
 * removing any duplicates.
 */
void
record_object_address_dependencies(const ObjectAddress *depender,
                                                   ObjectAddresses *referenced,
                                                   DependencyType behavior)
{
      eliminate_duplicate_dependencies(referenced);
      recordMultipleDependencies(depender,
                                             referenced->refs, referenced->numrefs,
                                             behavior);
}

/*
 * Clean up when done with an ObjectAddresses array.
 */
void
free_object_addresses(ObjectAddresses *addrs)
{
      pfree(addrs->refs);
      if (addrs->extras)
            pfree(addrs->extras);
      pfree(addrs);
}

/*
 * Determine the class of a given object identified by objectAddress.
 *
 * This function is essentially the reverse mapping for the object_classes[]
 * table.  We implement it as a function because the OIDs aren't consecutive.
 */
ObjectClass
getObjectClass(const ObjectAddress *object)
{
      switch (object->classId)
      {
            case RelationRelationId:
                  /* caller must check objectSubId */
                  return OCLASS_CLASS;

            case ProcedureRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_PROC;

            case TypeRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TYPE;

            case CastRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_CAST;

            case ConstraintRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_CONSTRAINT;

            case ConversionRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_CONVERSION;

            case AttrDefaultRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_DEFAULT;

            case LanguageRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_LANGUAGE;

            case OperatorRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_OPERATOR;

            case OperatorClassRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_OPCLASS;

            case OperatorFamilyRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_OPFAMILY;

            case AccessMethodOperatorRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_AMOP;

            case AccessMethodProcedureRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_AMPROC;

            case RewriteRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_REWRITE;

            case TriggerRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TRIGGER;

            case NamespaceRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_SCHEMA;

            case TSParserRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TSPARSER;

            case TSDictionaryRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TSDICT;

            case TSTemplateRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TSTEMPLATE;

            case TSConfigRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TSCONFIG;

            case AuthIdRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_ROLE;

            case DatabaseRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_DATABASE;

            case TableSpaceRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_TBLSPACE;

            case ForeignDataWrapperRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_FDW;

            case ForeignServerRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_FOREIGN_SERVER;

            case UserMappingRelationId:
                  Assert(object->objectSubId == 0);
                  return OCLASS_USER_MAPPING;
      }

      /* shouldn't get here */
      elog(ERROR, "unrecognized object class: %u", object->classId);
      return OCLASS_CLASS;          /* keep compiler quiet */
}

/*
 * getObjectDescription: build an object description for messages
 *
 * The result is a palloc'd string.
 */
char *
getObjectDescription(const ObjectAddress *object)
{
      StringInfoData buffer;

      initStringInfo(&buffer);

      switch (getObjectClass(object))
      {
            case OCLASS_CLASS:
                  getRelationDescription(&buffer, object->objectId);
                  if (object->objectSubId != 0)
                        appendStringInfo(&buffer, _(" column %s"),
                                                 get_relid_attribute_name(object->objectId,
                                                                                 object->objectSubId));
                  break;

            case OCLASS_PROC:
                  appendStringInfo(&buffer, _("function %s"),
                                           format_procedure(object->objectId));
                  break;

            case OCLASS_TYPE:
                  appendStringInfo(&buffer, _("type %s"),
                                           format_type_be(object->objectId));
                  break;

            case OCLASS_CAST:
                  {
                        Relation    castDesc;
                        ScanKeyData skey[1];
                        SysScanDesc rcscan;
                        HeapTuple   tup;
                        Form_pg_cast castForm;

                        castDesc = heap_open(CastRelationId, AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        rcscan = systable_beginscan(castDesc, CastOidIndexId, true,
                                                                  SnapshotNow, 1, skey);

                        tup = systable_getnext(rcscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for cast %u",
                                     object->objectId);

                        castForm = (Form_pg_cast) GETSTRUCT(tup);

                        appendStringInfo(&buffer, _("cast from %s to %s"),
                                                 format_type_be(castForm->castsource),
                                                 format_type_be(castForm->casttarget));

                        systable_endscan(rcscan);
                        heap_close(castDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_CONSTRAINT:
                  {
                        HeapTuple   conTup;
                        Form_pg_constraint con;

                        conTup = SearchSysCache(CONSTROID,
                                                            ObjectIdGetDatum(object->objectId),
                                                            0, 0, 0);
                        if (!HeapTupleIsValid(conTup))
                              elog(ERROR, "cache lookup failed for constraint %u",
                                     object->objectId);
                        con = (Form_pg_constraint) GETSTRUCT(conTup);

                        if (OidIsValid(con->conrelid))
                        {
                              StringInfoData rel;

                              initStringInfo(&rel);
                              getRelationDescription(&rel, con->conrelid);
                              appendStringInfo(&buffer, _("constraint %s on %s"),
                                                       NameStr(con->conname), rel.data);
                              pfree(rel.data);
                        }
                        else
                        {
                              appendStringInfo(&buffer, _("constraint %s"),
                                                       NameStr(con->conname));
                        }

                        ReleaseSysCache(conTup);
                        break;
                  }

            case OCLASS_CONVERSION:
                  {
                        HeapTuple   conTup;

                        conTup = SearchSysCache(CONVOID,
                                                            ObjectIdGetDatum(object->objectId),
                                                            0, 0, 0);
                        if (!HeapTupleIsValid(conTup))
                              elog(ERROR, "cache lookup failed for conversion %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("conversion %s"),
                         NameStr(((Form_pg_conversion) GETSTRUCT(conTup))->conname));
                        ReleaseSysCache(conTup);
                        break;
                  }

            case OCLASS_DEFAULT:
                  {
                        Relation    attrdefDesc;
                        ScanKeyData skey[1];
                        SysScanDesc adscan;
                        HeapTuple   tup;
                        Form_pg_attrdef attrdef;
                        ObjectAddress colobject;

                        attrdefDesc = heap_open(AttrDefaultRelationId, AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        adscan = systable_beginscan(attrdefDesc, AttrDefaultOidIndexId,
                                                                  true, SnapshotNow, 1, skey);

                        tup = systable_getnext(adscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for attrdef %u",
                                     object->objectId);

                        attrdef = (Form_pg_attrdef) GETSTRUCT(tup);

                        colobject.classId = RelationRelationId;
                        colobject.objectId = attrdef->adrelid;
                        colobject.objectSubId = attrdef->adnum;

                        appendStringInfo(&buffer, _("default for %s"),
                                                 getObjectDescription(&colobject));

                        systable_endscan(adscan);
                        heap_close(attrdefDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_LANGUAGE:
                  {
                        HeapTuple   langTup;

                        langTup = SearchSysCache(LANGOID,
                                                             ObjectIdGetDatum(object->objectId),
                                                             0, 0, 0);
                        if (!HeapTupleIsValid(langTup))
                              elog(ERROR, "cache lookup failed for language %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("language %s"),
                          NameStr(((Form_pg_language) GETSTRUCT(langTup))->lanname));
                        ReleaseSysCache(langTup);
                        break;
                  }

            case OCLASS_OPERATOR:
                  appendStringInfo(&buffer, _("operator %s"),
                                           format_operator(object->objectId));
                  break;

            case OCLASS_OPCLASS:
                  {
                        HeapTuple   opcTup;
                        Form_pg_opclass opcForm;
                        HeapTuple   amTup;
                        Form_pg_am  amForm;
                        char     *nspname;

                        opcTup = SearchSysCache(CLAOID,
                                                            ObjectIdGetDatum(object->objectId),
                                                            0, 0, 0);
                        if (!HeapTupleIsValid(opcTup))
                              elog(ERROR, "cache lookup failed for opclass %u",
                                     object->objectId);
                        opcForm = (Form_pg_opclass) GETSTRUCT(opcTup);

                        amTup = SearchSysCache(AMOID,
                                                         ObjectIdGetDatum(opcForm->opcmethod),
                                                         0, 0, 0);
                        if (!HeapTupleIsValid(amTup))
                              elog(ERROR, "cache lookup failed for access method %u",
                                     opcForm->opcmethod);
                        amForm = (Form_pg_am) GETSTRUCT(amTup);

                        /* Qualify the name if not visible in search path */
                        if (OpclassIsVisible(object->objectId))
                              nspname = NULL;
                        else
                              nspname = get_namespace_name(opcForm->opcnamespace);

                        appendStringInfo(&buffer, _("operator class %s for access method %s"),
                                                 quote_qualified_identifier(nspname,
                                                                          NameStr(opcForm->opcname)),
                                                 NameStr(amForm->amname));

                        ReleaseSysCache(amTup);
                        ReleaseSysCache(opcTup);
                        break;
                  }

            case OCLASS_OPFAMILY:
                  getOpFamilyDescription(&buffer, object->objectId);
                  break;

            case OCLASS_AMOP:
                  {
                        Relation    amopDesc;
                        ScanKeyData skey[1];
                        SysScanDesc amscan;
                        HeapTuple   tup;
                        Form_pg_amop amopForm;
                        StringInfoData opfam;

                        amopDesc = heap_open(AccessMethodOperatorRelationId,
                                                       AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        amscan = systable_beginscan(amopDesc, AccessMethodOperatorOidIndexId, true,
                                                                  SnapshotNow, 1, skey);

                        tup = systable_getnext(amscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for amop entry %u",
                                     object->objectId);

                        amopForm = (Form_pg_amop) GETSTRUCT(tup);

                        initStringInfo(&opfam);
                        getOpFamilyDescription(&opfam, amopForm->amopfamily);

                        /*
                         * translator: %d is the operator strategy (a number), the
                         * first %s is the textual form of the operator, and the
                         * second %s is the description of the operator family.
                         */
                        appendStringInfo(&buffer, _("operator %d %s of %s"),
                                                 amopForm->amopstrategy,
                                                 format_operator(amopForm->amopopr),
                                                 opfam.data);
                        pfree(opfam.data);

                        systable_endscan(amscan);
                        heap_close(amopDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_AMPROC:
                  {
                        Relation    amprocDesc;
                        ScanKeyData skey[1];
                        SysScanDesc amscan;
                        HeapTuple   tup;
                        Form_pg_amproc amprocForm;
                        StringInfoData opfam;

                        amprocDesc = heap_open(AccessMethodProcedureRelationId,
                                                         AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        amscan = systable_beginscan(amprocDesc, AccessMethodProcedureOidIndexId, true,
                                                                  SnapshotNow, 1, skey);

                        tup = systable_getnext(amscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for amproc entry %u",
                                     object->objectId);

                        amprocForm = (Form_pg_amproc) GETSTRUCT(tup);

                        initStringInfo(&opfam);
                        getOpFamilyDescription(&opfam, amprocForm->amprocfamily);

                        /*
                         * translator: %d is the function number, the first %s is the
                         * textual form of the function with arguments, and the second
                         * %s is the description of the operator family.
                         */
                        appendStringInfo(&buffer, _("function %d %s of %s"),
                                                 amprocForm->amprocnum,
                                                 format_procedure(amprocForm->amproc),
                                                 opfam.data);
                        pfree(opfam.data);

                        systable_endscan(amscan);
                        heap_close(amprocDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_REWRITE:
                  {
                        Relation    ruleDesc;
                        ScanKeyData skey[1];
                        SysScanDesc rcscan;
                        HeapTuple   tup;
                        Form_pg_rewrite rule;

                        ruleDesc = heap_open(RewriteRelationId, AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        rcscan = systable_beginscan(ruleDesc, RewriteOidIndexId, true,
                                                                  SnapshotNow, 1, skey);

                        tup = systable_getnext(rcscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for rule %u",
                                     object->objectId);

                        rule = (Form_pg_rewrite) GETSTRUCT(tup);

                        appendStringInfo(&buffer, _("rule %s on "),
                                                 NameStr(rule->rulename));
                        getRelationDescription(&buffer, rule->ev_class);

                        systable_endscan(rcscan);
                        heap_close(ruleDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_TRIGGER:
                  {
                        Relation    trigDesc;
                        ScanKeyData skey[1];
                        SysScanDesc tgscan;
                        HeapTuple   tup;
                        Form_pg_trigger trig;

                        trigDesc = heap_open(TriggerRelationId, AccessShareLock);

                        ScanKeyInit(&skey[0],
                                          ObjectIdAttributeNumber,
                                          BTEqualStrategyNumber, F_OIDEQ,
                                          ObjectIdGetDatum(object->objectId));

                        tgscan = systable_beginscan(trigDesc, TriggerOidIndexId, true,
                                                                  SnapshotNow, 1, skey);

                        tup = systable_getnext(tgscan);

                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "could not find tuple for trigger %u",
                                     object->objectId);

                        trig = (Form_pg_trigger) GETSTRUCT(tup);

                        appendStringInfo(&buffer, _("trigger %s on "),
                                                 NameStr(trig->tgname));
                        getRelationDescription(&buffer, trig->tgrelid);

                        systable_endscan(tgscan);
                        heap_close(trigDesc, AccessShareLock);
                        break;
                  }

            case OCLASS_SCHEMA:
                  {
                        char     *nspname;

                        nspname = get_namespace_name(object->objectId);
                        if (!nspname)
                              elog(ERROR, "cache lookup failed for namespace %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("schema %s"), nspname);
                        break;
                  }

            case OCLASS_TSPARSER:
                  {
                        HeapTuple   tup;

                        tup = SearchSysCache(TSPARSEROID,
                                                       ObjectIdGetDatum(object->objectId),
                                                       0, 0, 0);
                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "cache lookup failed for text search parser %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("text search parser %s"),
                               NameStr(((Form_pg_ts_parser) GETSTRUCT(tup))->prsname));
                        ReleaseSysCache(tup);
                        break;
                  }

            case OCLASS_TSDICT:
                  {
                        HeapTuple   tup;

                        tup = SearchSysCache(TSDICTOID,
                                                       ObjectIdGetDatum(object->objectId),
                                                       0, 0, 0);
                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "cache lookup failed for text search dictionary %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("text search dictionary %s"),
                                NameStr(((Form_pg_ts_dict) GETSTRUCT(tup))->dictname));
                        ReleaseSysCache(tup);
                        break;
                  }

            case OCLASS_TSTEMPLATE:
                  {
                        HeapTuple   tup;

                        tup = SearchSysCache(TSTEMPLATEOID,
                                                       ObjectIdGetDatum(object->objectId),
                                                       0, 0, 0);
                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "cache lookup failed for text search template %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("text search template %s"),
                          NameStr(((Form_pg_ts_template) GETSTRUCT(tup))->tmplname));
                        ReleaseSysCache(tup);
                        break;
                  }

            case OCLASS_TSCONFIG:
                  {
                        HeapTuple   tup;

                        tup = SearchSysCache(TSCONFIGOID,
                                                       ObjectIdGetDatum(object->objectId),
                                                       0, 0, 0);
                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "cache lookup failed for text search configuration %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("text search configuration %s"),
                               NameStr(((Form_pg_ts_config) GETSTRUCT(tup))->cfgname));
                        ReleaseSysCache(tup);
                        break;
                  }

            case OCLASS_ROLE:
                  {
                        appendStringInfo(&buffer, _("role %s"),
                                                 GetUserNameFromId(object->objectId));
                        break;
                  }

            case OCLASS_DATABASE:
                  {
                        char     *datname;

                        datname = get_database_name(object->objectId);
                        if (!datname)
                              elog(ERROR, "cache lookup failed for database %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("database %s"), datname);
                        break;
                  }

            case OCLASS_TBLSPACE:
                  {
                        char     *tblspace;

                        tblspace = get_tablespace_name(object->objectId);
                        if (!tblspace)
                              elog(ERROR, "cache lookup failed for tablespace %u",
                                     object->objectId);
                        appendStringInfo(&buffer, _("tablespace %s"), tblspace);
                        break;
                  }

            case OCLASS_FDW:
                  {
                        ForeignDataWrapper *fdw;

                        fdw = GetForeignDataWrapper(object->objectId);
                        appendStringInfo(&buffer, _("foreign-data wrapper %s"), fdw->fdwname);
                        break;
                  }

            case OCLASS_FOREIGN_SERVER:
                  {
                        ForeignServer *srv;

                        srv = GetForeignServer(object->objectId);
                        appendStringInfo(&buffer, _("server %s"), srv->servername);
                        break;
                  }

            case OCLASS_USER_MAPPING:
                  {
                        HeapTuple   tup;
                        Oid               useid;
                        char     *usename;

                        tup = SearchSysCache(USERMAPPINGOID,
                                                       ObjectIdGetDatum(object->objectId),
                                                       0, 0, 0);
                        if (!HeapTupleIsValid(tup))
                              elog(ERROR, "cache lookup failed for user mapping %u",
                                     object->objectId);

                        useid = ((Form_pg_user_mapping) GETSTRUCT(tup))->umuser;

                        ReleaseSysCache(tup);

                        if (OidIsValid(useid))
                              usename = GetUserNameFromId(useid);
                        else
                              usename = "public";

                        appendStringInfo(&buffer, _("user mapping for %s"), usename);
                        break;
                  }

            default:
                  appendStringInfo(&buffer, "unrecognized object %u %u %d",
                                           object->classId,
                                           object->objectId,
                                           object->objectSubId);
                  break;
      }

      return buffer.data;
}

/*
 * subroutine for getObjectDescription: describe a relation
 */
static void
getRelationDescription(StringInfo buffer, Oid relid)
{
      HeapTuple   relTup;
      Form_pg_class relForm;
      char     *nspname;
      char     *relname;

      relTup = SearchSysCache(RELOID,
                                          ObjectIdGetDatum(relid),
                                          0, 0, 0);
      if (!HeapTupleIsValid(relTup))
            elog(ERROR, "cache lookup failed for relation %u", relid);
      relForm = (Form_pg_class) GETSTRUCT(relTup);

      /* Qualify the name if not visible in search path */
      if (RelationIsVisible(relid))
            nspname = NULL;
      else
            nspname = get_namespace_name(relForm->relnamespace);

      relname = quote_qualified_identifier(nspname, NameStr(relForm->relname));

      switch (relForm->relkind)
      {
            case RELKIND_RELATION:
                  appendStringInfo(buffer, _("table %s"),
                                           relname);
                  break;
            case RELKIND_INDEX:
                  appendStringInfo(buffer, _("index %s"),
                                           relname);
                  break;
            case RELKIND_SEQUENCE:
                  appendStringInfo(buffer, _("sequence %s"),
                                           relname);
                  break;
            case RELKIND_UNCATALOGED:
                  appendStringInfo(buffer, _("uncataloged table %s"),
                                           relname);
                  break;
            case RELKIND_TOASTVALUE:
                  appendStringInfo(buffer, _("toast table %s"),
                                           relname);
                  break;
            case RELKIND_VIEW:
                  appendStringInfo(buffer, _("view %s"),
                                           relname);
                  break;
            case RELKIND_COMPOSITE_TYPE:
                  appendStringInfo(buffer, _("composite type %s"),
                                           relname);
                  break;
            default:
                  /* shouldn't get here */
                  appendStringInfo(buffer, _("relation %s"),
                                           relname);
                  break;
      }

      ReleaseSysCache(relTup);
}

/*
 * subroutine for getObjectDescription: describe an operator family
 */
static void
getOpFamilyDescription(StringInfo buffer, Oid opfid)
{
      HeapTuple   opfTup;
      Form_pg_opfamily opfForm;
      HeapTuple   amTup;
      Form_pg_am  amForm;
      char     *nspname;

      opfTup = SearchSysCache(OPFAMILYOID,
                                          ObjectIdGetDatum(opfid),
                                          0, 0, 0);
      if (!HeapTupleIsValid(opfTup))
            elog(ERROR, "cache lookup failed for opfamily %u", opfid);
      opfForm = (Form_pg_opfamily) GETSTRUCT(opfTup);

      amTup = SearchSysCache(AMOID,
                                       ObjectIdGetDatum(opfForm->opfmethod),
                                       0, 0, 0);
      if (!HeapTupleIsValid(amTup))
            elog(ERROR, "cache lookup failed for access method %u",
                   opfForm->opfmethod);
      amForm = (Form_pg_am) GETSTRUCT(amTup);

      /* Qualify the name if not visible in search path */
      if (OpfamilyIsVisible(opfid))
            nspname = NULL;
      else
            nspname = get_namespace_name(opfForm->opfnamespace);

      appendStringInfo(buffer, _("operator family %s for access method %s"),
                               quote_qualified_identifier(nspname,
                                                                        NameStr(opfForm->opfname)),
                               NameStr(amForm->amname));

      ReleaseSysCache(amTup);
      ReleaseSysCache(opfTup);
}

Generated by  Doxygen 1.6.0   Back to index