greenplumn dependency 源码
greenplumn dependency 代码
文件路径：/src/backend/catalog/dependency.c
/*-------------------------------------------------------------------------
*
* dependency.c
* Routines to support inter-object dependencies.
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/catalog/dependency.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/htup_details.h"
#include "access/table.h"
#include "access/xact.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_am.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_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_conversion.h"
#include "catalog/pg_database.h"
#include "catalog/pg_default_acl.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_event_trigger.h"
#include "catalog/pg_extension.h"
#include "catalog/pg_foreign_data_wrapper.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_init_privs.h"
#include "catalog/pg_language.h"
#include "catalog/pg_largeobject.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_policy.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_publication.h"
#include "catalog/pg_publication_rel.h"
#include "catalog/pg_rewrite.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_transform.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_type_encoding.h"
#include "catalog/pg_user_mapping.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
#include "commands/extension.h"
#include "commands/policy.h"
#include "commands/proclang.h"
#include "commands/publicationcmds.h"
#include "commands/schemacmds.h"
#include "commands/seclabel.h"
#include "commands/sequence.h"
#include "commands/trigger.h"
#include "commands/typecmds.h"
#include "foreign/foreign.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 "catalog/pg_compression.h"
#include "catalog/pg_extprotocol.h"
#include "commands/tablespace.h"
#include "cdb/cdbvars.h"
#include "commands/extprotocolcmds.h"
#include "commands/tablecmds.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 */
#define DEPFLAG_PARTITION 0x0010 /* reached via partition dependency */
#define DEPFLAG_EXTENSION 0x0020 /* reached via extension dependency */
#define DEPFLAG_REVERSE 0x0040 /* reverse internal/extension link */
#define DEPFLAG_IS_PART 0x0080 /* has a partition dependency */
#define DEPFLAG_SUBOBJECT 0x0100 /* subobject of another deletable object */
/* 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;
/* temporary storage in findDependentObjects */
typedef struct
{
ObjectAddress obj; /* object to be deleted --- MUST BE FIRST */
int subflags; /* flags to pass down when recursing to obj */
} ObjectAddressAndFlags;
/* 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[] = {
RelationRelationId, /* OCLASS_CLASS */
ProcedureRelationId, /* OCLASS_PROC */
TypeRelationId, /* OCLASS_TYPE */
CastRelationId, /* OCLASS_CAST */
CollationRelationId, /* OCLASS_COLLATION */
ConstraintRelationId, /* OCLASS_CONSTRAINT */
ConversionRelationId, /* OCLASS_CONVERSION */
AttrDefaultRelationId, /* OCLASS_DEFAULT */
LanguageRelationId, /* OCLASS_LANGUAGE */
LargeObjectRelationId, /* OCLASS_LARGEOBJECT */
OperatorRelationId, /* OCLASS_OPERATOR */
OperatorClassRelationId, /* OCLASS_OPCLASS */
OperatorFamilyRelationId, /* OCLASS_OPFAMILY */
AccessMethodRelationId, /* OCLASS_AM */
AccessMethodOperatorRelationId, /* OCLASS_AMOP */
AccessMethodProcedureRelationId, /* OCLASS_AMPROC */
RewriteRelationId, /* OCLASS_REWRITE */
TriggerRelationId, /* OCLASS_TRIGGER */
NamespaceRelationId, /* OCLASS_SCHEMA */
StatisticExtRelationId, /* OCLASS_STATISTIC_EXT */
TSParserRelationId, /* OCLASS_TSPARSER */
TSDictionaryRelationId, /* OCLASS_TSDICT */
TSTemplateRelationId, /* OCLASS_TSTEMPLATE */
TSConfigRelationId, /* OCLASS_TSCONFIG */
AuthIdRelationId, /* OCLASS_ROLE */
DatabaseRelationId, /* OCLASS_DATABASE */
TableSpaceRelationId, /* OCLASS_TBLSPACE */
ForeignDataWrapperRelationId, /* OCLASS_FDW */
ForeignServerRelationId, /* OCLASS_FOREIGN_SERVER */
UserMappingRelationId, /* OCLASS_USER_MAPPING */
DefaultAclRelationId, /* OCLASS_DEFACL */
ExtensionRelationId, /* OCLASS_EXTENSION */
EventTriggerRelationId, /* OCLASS_EVENT_TRIGGER */
PolicyRelationId, /* OCLASS_POLICY */
PublicationRelationId, /* OCLASS_PUBLICATION */
PublicationRelRelationId, /* OCLASS_PUBLICATION_REL */
SubscriptionRelationId, /* OCLASS_SUBSCRIPTION */
TransformRelationId, /* OCLASS_TRANSFORM */
/* GPDB additions */
ExtprotocolRelationId /* OCLASS_EXTPROTOCOL */
};
static void findDependentObjects(const ObjectAddress *object,
int objflags,
int flags,
ObjectAddressStack *stack,
ObjectAddresses *targetObjects,
const ObjectAddresses *pendingObjects,
Relation *depRel);
static void reportDependentObjects(const ObjectAddresses *targetObjects,
DropBehavior behavior,
int flags,
const ObjectAddress *origObject);
static void deleteOneObject(const ObjectAddress *object,
Relation *depRel, int32 flags);
static void doDeletion(const ObjectAddress *object, int flags);
static void AcquireDeletionLock(const ObjectAddress *object, int flags);
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 bool stack_address_present_add_flags(const ObjectAddress *object,
int flags,
ObjectAddressStack *stack);
static void DeleteInitPrivs(const ObjectAddress *object);
/*
* Go through the objects given running the final actions on them, and execute
* the actual deletion.
*/
static void
deleteObjectsInList(ObjectAddresses *targetObjects, Relation *depRel,
int flags)
{
int i;
/*
* Keep track of objects for event triggers, if necessary.
*/
if (trackDroppedObjectsNeeded() && !(flags & PERFORM_DELETION_INTERNAL))
{
for (i = 0; i < targetObjects->numrefs; i++)
{
const ObjectAddress *thisobj = &targetObjects->refs[i];
const ObjectAddressExtra *extra = &targetObjects->extras[i];
bool original = false;
bool normal = false;
if (extra->flags & DEPFLAG_ORIGINAL)
original = true;
if (extra->flags & DEPFLAG_NORMAL)
normal = true;
if (extra->flags & DEPFLAG_REVERSE)
normal = true;
if (EventTriggerSupportsObjectClass(getObjectClass(thisobj)))
{
EventTriggerSQLDropAddObject(thisobj, original, normal);
}
}
}
/*
* Delete all the objects in the proper order, except that if told to, we
* should skip the original object(s).
*/
for (i = 0; i < targetObjects->numrefs; i++)
{
ObjectAddress *thisobj = targetObjects->refs + i;
ObjectAddressExtra *thisextra = targetObjects->extras + i;
if ((flags & PERFORM_DELETION_SKIP_ORIGINAL) &&
(thisextra->flags & DEPFLAG_ORIGINAL))
continue;
deleteOneObject(thisobj, depRel, flags);
}
}
/*
* 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 performMultipleDeletions
* is a variant on the same theme; if you change anything here you'll likely
* need to fix that too.
*
* Bits in the flags argument can include:
*
* PERFORM_DELETION_INTERNAL: indicates that the drop operation is not the
* direct result of a user-initiated action. For example, when a temporary
* schema is cleaned out so that a new backend can use it, or when a column
* default is dropped as an intermediate step while adding a new one, that's
* an internal operation. On the other hand, when we drop something because
* the user issued a DROP statement against it, that's not internal. Currently
* this suppresses calling event triggers and making some permissions checks.
*
* PERFORM_DELETION_CONCURRENTLY: perform the drop concurrently. This does
* not currently work for anything except dropping indexes; don't set it for
* other object types or you may get strange results.
*
* PERFORM_DELETION_QUIETLY: reduce message level from NOTICE to DEBUG2.
*
* PERFORM_DELETION_SKIP_ORIGINAL: do not delete the specified object(s),
* but only what depends on it/them.
*
* PERFORM_DELETION_SKIP_EXTENSIONS: do not delete extensions, even when
* deleting objects that are part of an extension. This should generally
* be used only when dropping temporary objects.
*
* PERFORM_DELETION_CONCURRENT_LOCK: perform the drop normally but with a lock
* as if it were concurrent. This is used by REINDEX CONCURRENTLY.
*
*/
void
performDeletion(const ObjectAddress *object,
DropBehavior behavior, int flags)
{
Relation depRel;
ObjectAddresses *targetObjects;
/*
* We save some cycles by opening pg_depend just once and passing the
* Relation pointer down to all the recursive deletion steps.
*/
depRel = table_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, 0);
/*
* 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,
flags,
NULL, /* empty stack */
targetObjects,
NULL, /* no pendingObjects */
&depRel);
/*
* Check if deletion is allowed, and report about cascaded deletes.
*/
reportDependentObjects(targetObjects,
behavior,
flags,
object);
/* do the deed */
deleteObjectsInList(targetObjects, &depRel, flags);
/* And clean up */
free_object_addresses(targetObjects);
table_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, int flags)
{
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 = table_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, flags);
findDependentObjects(thisobj,
DEPFLAG_ORIGINAL,
flags,
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,
flags,
(objects->numrefs == 1 ? objects->refs : NULL));
/* do the deed */
deleteObjectsInList(targetObjects, &depRel, flags);
/* And clean up */
free_object_addresses(targetObjects);
table_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
* objflags: flags to be ORed into the object's targetObjects entry
* flags: PERFORM_DELETION_xxx flags for the deletion operation as a whole
* 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
*
* Note: objflags describes the reason for visiting this particular object
* at this time, and is not passed down when recursing. The flags argument
* is passed down, since it describes what we're doing overall.
*/
static void
findDependentObjects(const ObjectAddress *object,
int objflags,
int flags,
ObjectAddressStack *stack,
ObjectAddresses *targetObjects,
const ObjectAddresses *pendingObjects,
Relation *depRel)
{
ScanKeyData key[3];
int nkeys;
SysScanDesc scan;
HeapTuple tup;
ObjectAddress otherObject;
ObjectAddress owningObject;
ObjectAddress partitionObject;
ObjectAddressAndFlags *dependentObjects;
int numDependentObjects;
int maxDependentObjects;
ObjectAddressStack mystack;
ObjectAddressExtra extra;
/*
* If the target object is already being visited in an outer recursion
* level, just report the current objflags 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.
*/
if (stack_address_present_add_flags(object, objflags, stack))
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 objflags 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, objflags, targetObjects))
return;
/*
* The target object might be internally dependent on some other object
* (its "owner"), and/or be a member of an extension (also considered 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.
*/
/*
* Step 1: find and remove pg_depend records that link from this object to
* others. We have to do this anyway, and doing it first ensures that we
* avoid infinite recursion in the case of cycles. Also, some dependency
* types require extra processing here.
*
* 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,
NULL, nkeys, key);
/* initialize variables that loop may fill */
memset(&owningObject, 0, sizeof(owningObject));
memset(&partitionObject, 0, sizeof(partitionObject));
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:
case DEPENDENCY_AUTO_EXTENSION:
/* no problem */
break;
case DEPENDENCY_EXTENSION:
/*
* If told to, ignore EXTENSION dependencies altogether. This
* flag is normally used to prevent dropping extensions during
* temporary-object cleanup, even if a temp object was created
* during an extension script.
*/
if (flags & PERFORM_DELETION_SKIP_EXTENSIONS)
break;
/*
* If the other object is the extension currently being
* created/altered, ignore this dependency and continue with
* the deletion. This allows dropping of an extension's
* objects within the extension's scripts, as well as corner
* cases such as dropping a transient object created within
* such a script.
*/
if (creating_extension &&
otherObject.classId == ExtensionRelationId &&
otherObject.objectId == CurrentExtensionObject)
break;
/* Otherwise, treat this like an internal dependency */
/* FALL THRU */
case DEPENDENCY_INTERNAL:
/*
* This object is part of the internal implementation of
* another object, or is part of the extension that is the
* other object. We have three cases:
*
* 1. At the outermost recursion level, we must disallow the
* DROP. However, if the owning 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.
*
* Note: the above statement is true only if this pg_depend
* entry still exists by then; in principle, therefore, we
* could miss deleting an item the user told us to delete.
* However, no inconsistency can result: since we're at outer
* level, there is no object depending on this one.
*/
if (stack == NULL)
{
if (pendingObjects &&
object_address_present(&otherObject, pendingObjects))
{
systable_endscan(scan);
/* need to release caller's lock; see notes below */
ReleaseDeletionLock(object);
return;
}
/*
* We postpone actually issuing the error message until
* after this loop, so that we can make the behavior
* independent of the ordering of pg_depend entries, at
* least if there's not more than one INTERNAL and one
* EXTENSION dependency. (If there's more, we'll complain
* about a random one of them.) Prefer to complain about
* EXTENSION, since that's generally a more important
* dependency.
*/
if (!OidIsValid(owningObject.classId) ||
foundDep->deptype == DEPENDENCY_EXTENSION)
owningObject = otherObject;
break;
}
/*
* 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. Since there can be more
* than one "owning" object, we have to allow matches that are
* more than one level down in the stack.
*/
if (stack_address_present_add_flags(&otherObject, 0, stack))
break;
/*
* 3. Not all the owning objects have been visited, so
* transform this deletion request into a delete of this
* owning object.
*
* First, release caller's lock on this object and get
* deletion lock on the owning object. (We must release
* caller's lock to avoid deadlock against a concurrent
* deletion of the owning object.)
*/
ReleaseDeletionLock(object);
AcquireDeletionLock(&otherObject, 0);
/*
* The owning 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;
}
/*
* One way or the other, we're done with the scan; might as
* well close it down before recursing, to reduce peak
* resource consumption.
*/
systable_endscan(scan);
/*
* Okay, recurse to the owning object instead of proceeding.
*
* We do not need to stack the current object; we want the
* traversal order to be as if the original reference had
* linked to the owning object instead of this one.
*
* The dependency type is a "reverse" dependency: we need to
* delete the owning object if this one is to be deleted, but
* this linkage is never a reason for an automatic deletion.
*/
findDependentObjects(&otherObject,
DEPFLAG_REVERSE,
flags,
stack,
targetObjects,
pendingObjects,
depRel);
/*
* The current target object should have been added to
* targetObjects while processing the owning object; but it
* probably got only the flag bits associated with the
* dependency we're looking at. We need to add the objflags
* that were passed to this recursion level, too, else we may
* get a bogus failure in reportDependentObjects (if, for
* example, we were called due to a partition dependency).
*
* If somehow the current object didn't get scheduled for
* deletion, bleat. (That would imply that somebody deleted
* this dependency record before the recursion got to it.)
* Another idea would be to reacquire lock on the current
* object and resume trying to delete it, but it seems not
* worth dealing with the race conditions inherent in that.
*/
if (!object_address_present_add_flags(object, objflags,
targetObjects))
elog(ERROR, "deletion of owning object %s failed to delete %s",
getObjectDescription(&otherObject),
getObjectDescription(object));
/* And we're done here. */
return;
case DEPENDENCY_PARTITION_PRI:
/*
* Remember that this object has a partition-type dependency.
* After the dependency scan, we'll complain if we didn't find
* a reason to delete one of its partition dependencies.
*/
objflags |= DEPFLAG_IS_PART;
/*
* Also remember the primary partition owner, for error
* messages. If there are multiple primary owners (which
* there should not be), we'll report a random one of them.
*/
partitionObject = otherObject;
break;
case DEPENDENCY_PARTITION_SEC:
/*
* Only use secondary partition owners in error messages if we
* find no primary owner (which probably shouldn't happen).
*/
if (!(objflags & DEPFLAG_IS_PART))
partitionObject = otherObject;
/*
* Remember that this object has a partition-type dependency.
* After the dependency scan, we'll complain if we didn't find
* a reason to delete one of its partition dependencies.
*/
objflags |= DEPFLAG_IS_PART;
break;
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);
/*
* If we found an INTERNAL or EXTENSION dependency when we're at outer
* level, complain about it now. If we also found a PARTITION dependency,
* we prefer to report the PARTITION dependency. This is arbitrary but
* seems to be more useful in practice.
*/
if (OidIsValid(owningObject.classId))
{
char *otherObjDesc;
if (OidIsValid(partitionObject.classId))
otherObjDesc = getObjectDescription(&partitionObject);
else
otherObjDesc = getObjectDescription(&owningObject);
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)));
}
/*
* Next, identify all objects that directly depend on the current object.
* To ensure predictable deletion order, we collect them up in
* dependentObjects and sort the list before actually recursing. (The
* deletion order would be valid in any case, but doing this ensures
* consistent output from DROP CASCADE commands, which is helpful for
* regression testing.)
*/
maxDependentObjects = 128; /* arbitrary initial allocation */
dependentObjects = (ObjectAddressAndFlags *)
palloc(maxDependentObjects * sizeof(ObjectAddressAndFlags));
numDependentObjects = 0;
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,
NULL, 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, 0);
/*
* 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;
}
/*
* We do need to delete it, so identify objflags to be passed down,
* which depend on the dependency type.
*/
switch (foundDep->deptype)
{
case DEPENDENCY_NORMAL:
subflags = DEPFLAG_NORMAL;
break;
case DEPENDENCY_AUTO:
case DEPENDENCY_AUTO_EXTENSION:
subflags = DEPFLAG_AUTO;
break;
case DEPENDENCY_INTERNAL:
subflags = DEPFLAG_INTERNAL;
break;
case DEPENDENCY_PARTITION_PRI:
case DEPENDENCY_PARTITION_SEC:
subflags = DEPFLAG_PARTITION;
break;
case DEPENDENCY_EXTENSION:
subflags = DEPFLAG_EXTENSION;
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;
}
/* And add it to the pending-objects list */
if (numDependentObjects >= maxDependentObjects)
{
/* enlarge array if needed */
maxDependentObjects *= 2;
dependentObjects = (ObjectAddressAndFlags *)
repalloc(dependentObjects,
maxDependentObjects * sizeof(ObjectAddressAndFlags));
}
dependentObjects[numDependentObjects].obj = otherObject;
dependentObjects[numDependentObjects].subflags = subflags;
numDependentObjects++;
}
systable_endscan(scan);
/*
* Now we can sort the dependent objects into a stable visitation order.
* It's safe to use object_address_comparator here since the obj field is
* first within ObjectAddressAndFlags.
*/
if (numDependentObjects > 1)
qsort((void *) dependentObjects, numDependentObjects,
sizeof(ObjectAddressAndFlags),
object_address_comparator);
/*
* Now recurse to the 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 = objflags;
mystack.next = stack;
for (int i = 0; i < numDependentObjects; i++)
{
ObjectAddressAndFlags *depObj = dependentObjects + i;
findDependentObjects(&depObj->obj,
depObj->subflags,
flags,
&mystack,
targetObjects,
pendingObjects,
depRel);
}
pfree(dependentObjects);
/*
* 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. Record the "dependee" as being either the most important
* partition owner if there is one, else the object we recursed from, if
* any. (The logic in reportDependentObjects() is such that it can only
* need one of those objects.)
*/
extra.flags = mystack.flags;
if (extra.flags & DEPFLAG_IS_PART)
extra.dependee = partitionObject;
else 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
* flags: other flags for the deletion operation
* 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 flags,
const ObjectAddress *origObject)
{
int msglevel = (flags & PERFORM_DELETION_QUIETLY) ? DEBUG2 : NOTICE;
bool ok = true;
StringInfoData clientdetail;
StringInfoData logdetail;
int numReportedClient = 0;
int numNotReportedClient = 0;
int i;
/*
* If we need to delete any partition-dependent objects, make sure that
* we're deleting at least one of their partition dependencies, too. That
* can be detected by checking that we reached them by a PARTITION
* dependency at some point.
*
* We just report the first such object, as in most cases the only way to
* trigger this complaint is to explicitly try to delete one partition of
* a partitioned object.
*/
for (i = 0; i < targetObjects->numrefs; i++)
{
const ObjectAddressExtra *extra = &targetObjects->extras[i];
if ((extra->flags & DEPFLAG_IS_PART) &&
!(extra->flags & DEPFLAG_PARTITION))
{
const ObjectAddress *object = &targetObjects->refs[i];
char *otherObjDesc = getObjectDescription(&extra->dependee);
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)));
}
}
/*
* 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 rest 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;
/* Also ignore sub-objects; we'll report the whole object elsewhere */
if (extra->flags & DEPFLAG_SUBOBJECT)
continue;
objDesc = getObjectDescription(obj);
/*
* If, at any stage of the recursive search, we reached the object via
* an AUTO, INTERNAL, PARTITION, or EXTENSION dependency, then it's
* okay to delete it even in RESTRICT mode.
*/
if (extra->flags & (DEPFLAG_AUTO |
DEPFLAG_INTERNAL |
DEPFLAG_PARTITION |
DEPFLAG_EXTENSION))
{
/*
* 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 (msglevel == NOTICE && Gp_role == GP_ROLE_EXECUTE)
{
ereport(DEBUG1,
(errmsg("%s depends on %s",
objDesc, otherDesc)));
}
else
{
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 (Gp_role == GP_ROLE_EXECUTE)
{
ereport(DEBUG1,
(errmsg("drop cascades to %s",
objDesc)));
}
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, int flags)
{
ScanKeyData key[3];
int nkeys;
SysScanDesc scan;
HeapTuple tup;
/* DROP hook of the objects being removed */
InvokeObjectDropHookArg(object->classId, object->objectId,
object->objectSubId, flags);
/*
* Close depRel if we are doing a drop concurrently. The object deletion
* subroutine will commit the current transaction, so we can't keep the
* relation open across doDeletion().
*/
if (flags & PERFORM_DELETION_CONCURRENTLY)
table_close(*depRel, RowExclusiveLock);
/*
* Delete the object itself, in an object-type-dependent way.
*
* We used to do this after removing the outgoing dependency links, but it
* seems just as reasonable to do it beforehand. In the concurrent case
* we *must* do it in this order, because we can't make any transactional
* updates before calling doDeletion() --- they'd get committed right
* away, which is not cool if the deletion then fails.
*/
doDeletion(object, flags);
/*
* Reopen depRel if we closed it above
*/
if (flags & PERFORM_DELETION_CONCURRENTLY)
*depRel = table_open(DependRelationId, RowExclusiveLock);
/*
* Now 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,
NULL, nkeys, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
CatalogTupleDelete(*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);
/*
* Delete any comments, security labels, or initial privileges associated
* with this object. (This is a convenient place to do these things,
* rather than having every object type know to do it.)
*/
DeleteComments(object->objectId, object->classId, object->objectSubId);
DeleteSecurityLabel(object);
DeleteInitPrivs(object);
/*
* 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, int flags)
{
switch (getObjectClass(object))
{
case OCLASS_CLASS:
{
char relKind = get_rel_relkind(object->objectId);
if (relKind == RELKIND_INDEX ||
relKind == RELKIND_PARTITIONED_INDEX)
{
bool concurrent = ((flags & PERFORM_DELETION_CONCURRENTLY) != 0);
bool concurrent_lock_mode = ((flags & PERFORM_DELETION_CONCURRENT_LOCK) != 0);
Assert(object->objectSubId == 0);
index_drop(object->objectId, concurrent, concurrent_lock_mode);
}
else
{
if (object->objectSubId != 0)
RemoveAttributeById(object->objectId,
object->objectSubId);
else
heap_drop_with_catalog(object->objectId);
}
/*
* for a sequence, in addition to dropping the heap, also
* delete pg_sequence tuple
*/
if (relKind == RELKIND_SEQUENCE)
DeleteSequenceTuple(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_COLLATION:
RemoveCollationById(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_LARGEOBJECT:
LargeObjectDrop(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_AM:
RemoveAccessMethodById(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_STATISTIC_EXT:
RemoveStatisticsById(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;
/*
* OCLASS_ROLE, OCLASS_DATABASE, OCLASS_TBLSPACE intentionally not
* handled here
*/
case OCLASS_FDW:
RemoveForeignDataWrapperById(object->objectId);
break;
case OCLASS_FOREIGN_SERVER:
RemoveForeignServerById(object->objectId);
break;
case OCLASS_USER_MAPPING:
RemoveUserMappingById(object->objectId);
break;
case OCLASS_DEFACL:
RemoveDefaultACLById(object->objectId);
break;
case OCLASS_EXTENSION:
RemoveExtensionById(object->objectId);
break;
case OCLASS_EVENT_TRIGGER:
RemoveEventTriggerById(object->objectId);
break;
case OCLASS_EXTPROTOCOL:
RemoveExtProtocolById(object->objectId);
break;
case OCLASS_POLICY:
RemovePolicyById(object->objectId);
break;
case OCLASS_PUBLICATION:
RemovePublicationById(object->objectId);
break;
case OCLASS_PUBLICATION_REL:
RemovePublicationRelById(object->objectId);
break;
case OCLASS_TRANSFORM:
DropTransformById(object->objectId);
break;
/*
* These global object types are not supported here.
*/
case OCLASS_ROLE:
case OCLASS_DATABASE:
case OCLASS_TBLSPACE:
case OCLASS_SUBSCRIPTION:
elog(ERROR, "global objects cannot be deleted by doDeletion");
break;
/*
* There's intentionally no default: case here; we want the
* compiler to warn if a new OCLASS hasn't been handled above.
*/
}
}
/*
* 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, int flags)
{
if (object->classId == RelationRelationId)
{
/*
* In DROP INDEX CONCURRENTLY, take only ShareUpdateExclusiveLock on
* the index for the moment. index_drop() will promote the lock once
* it's safe to do so. In all other cases we need full exclusive
* lock.
*/
if (flags & PERFORM_DELETION_CONCURRENTLY)
LockRelationOid(object->objectId, ShareUpdateExclusiveLock);
else
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.
*
* NOTE: the caller should ensure that a whole-table dependency on the
* specified relation is created separately, if one is needed. In particular,
* a whole-row Var "relation.*" will not cause this routine to emit any
* dependency item. This is appropriate behavior for subexpressions of an
* ordinary query, so other cases need to cope as necessary.
*/
void
recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
Node *expr, Oid relId,
DependencyType behavior,
DependencyType self_behavior,
bool ignore_self)
{
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;
rte.relkind = RELKIND_RELATION; /* no need for exactness here */
rte.rellockmode = AccessShareLock;
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 */
if (!ignore_self)
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.
*
* Similarly, we don't need to create dependencies on collations except where
* the collation is being freshly introduced to the expression.
*/
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. (We assume that there is a whole-table dependency
* arising from each underlying rangetable entry. While we could
* record such a dependency when finding a whole-row Var that
* references a relation directly, it's quite unclear how to extend
* that to whole-row Vars for JOINs, so it seems better to leave the
* responsibility with the range table. Note that this poses some
* risks for identifying dependencies of stand-alone expressions:
* whole-table references may need to be created separately.)
*/
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);
/*
* We must also depend on the constant's collation: it could be
* different from the datatype's, if a CollateExpr was const-folded to
* a simple constant. However we can save work in the most common
* case where the collation is "default", since we know that's pinned.
*/
if (OidIsValid(con->constcollid) &&
con->constcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, con->constcollid, 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 (SearchSysCacheExists1(PROCOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_PROC, objoid, 0,
context->addrs);
break;
case REGOPEROID:
case REGOPERATOROID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(OPEROID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_OPERATOR, objoid, 0,
context->addrs);
break;
case REGCLASSOID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(RELOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_CLASS, objoid, 0,
context->addrs);
break;
case REGTYPEOID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(TYPEOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_TYPE, objoid, 0,
context->addrs);
break;
case REGCONFIGOID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(TSCONFIGOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_TSCONFIG, objoid, 0,
context->addrs);
break;
case REGDICTIONARYOID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(TSDICTOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_TSDICT, objoid, 0,
context->addrs);
break;
case REGNAMESPACEOID:
objoid = DatumGetObjectId(con->constvalue);
if (SearchSysCacheExists1(NAMESPACEOID,
ObjectIdGetDatum(objoid)))
add_object_address(OCLASS_SCHEMA, objoid, 0,
context->addrs);
break;
/*
* Dependencies for regrole should be shared among all
* databases, so explicitly inhibit to have dependencies.
*/
case REGROLEOID:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("constant of the type %s cannot be used here",
"regrole")));
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);
/* and its collation, just as for Consts */
if (OidIsValid(param->paramcollid) &&
param->paramcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, param->paramcollid, 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, NullIfExpr))
{
NullIfExpr *nullifexpr = (NullIfExpr *) node;
add_object_address(OCLASS_OPERATOR, nullifexpr->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, 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, FieldSelect))
{
FieldSelect *fselect = (FieldSelect *) node;
Oid argtype = getBaseType(exprType((Node *) fselect->arg));
Oid reltype = get_typ_typrelid(argtype);
/*
* We need a dependency on the specific column named in FieldSelect,
* assuming we can identify the pg_class OID for it. (Probably we
* always can at the moment, but in future it might be possible for
* argtype to be RECORDOID.) If we can make a column dependency then
* we shouldn't need a dependency on the column's type; but if we
* can't, make a dependency on the type, as it might not appear
* anywhere else in the expression.
*/
if (OidIsValid(reltype))
add_object_address(OCLASS_CLASS, reltype, fselect->fieldnum,
context->addrs);
else
add_object_address(OCLASS_TYPE, fselect->resulttype, 0,
context->addrs);
/* the collation might not be referenced anywhere else, either */
if (OidIsValid(fselect->resultcollid) &&
fselect->resultcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
context->addrs);
}
else if (IsA(node, FieldStore))
{
FieldStore *fstore = (FieldStore *) node;
Oid reltype = get_typ_typrelid(fstore->resulttype);
/* similar considerations to FieldSelect, but multiple column(s) */
if (OidIsValid(reltype))
{
ListCell *l;
foreach(l, fstore->fieldnums)
add_object_address(OCLASS_CLASS, reltype, lfirst_int(l),
context->addrs);
}
else
add_object_address(OCLASS_TYPE, fstore->resulttype, 0,
context->addrs);
}
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);
/* the collation might not be referenced anywhere else, either */
if (OidIsValid(relab->resultcollid) &&
relab->resultcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, relab->resultcollid, 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);
/* the collation might not be referenced anywhere else, either */
if (OidIsValid(iocoerce->resultcollid) &&
iocoerce->resultcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
context->addrs);
}
else if (IsA(node, ArrayCoerceExpr))
{
ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;
/* as above, depend on type */
add_object_address(OCLASS_TYPE, acoerce->resulttype, 0,
context->addrs);
/* the collation might not be referenced anywhere else, either */
if (OidIsValid(acoerce->resultcollid) &&
acoerce->resultcollid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 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, CollateExpr))
{
CollateExpr *coll = (CollateExpr *) node;
add_object_address(OCLASS_COLLATION, coll->collOid, 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, NextValueExpr))
{
NextValueExpr *nve = (NextValueExpr *) node;
add_object_address(OCLASS_CLASS, nve->seqid, 0,
context->addrs);
}
else if (IsA(node, OnConflictExpr))
{
OnConflictExpr *onconflict = (OnConflictExpr *) node;
if (OidIsValid(onconflict->constraint))
add_object_address(OCLASS_CONSTRAINT, onconflict->constraint, 0,
context->addrs);
/* fall through to examine arguments */
}
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, WindowClause))
{
WindowClause *wc = (WindowClause *) node;
if (OidIsValid(wc->startInRangeFunc))
add_object_address(OCLASS_PROC, wc->startInRangeFunc, 0,
context->addrs);
if (OidIsValid(wc->endInRangeFunc))
add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
context->addrs);
if (OidIsValid(wc->inRangeColl) &&
wc->inRangeColl != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
context->addrs);
/* fall through to examine substructure */
}
else if (IsA(node, Query))
{
/* Recurse into RTE subquery or not-yet-planned sublink subquery */
Query *query = (Query *) node;
ListCell *lc;
bool result;
/*
* Add whole-relation refs for each plain relation mentioned in the
* subquery's rtable.
*
* 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.
*
* Note: we don't need to worry about collations mentioned in
* RTE_VALUES or RTE_CTE RTEs, because those must just duplicate
* collations referenced in other parts of the Query. We do have to
* worry about collations mentioned in RTE_FUNCTION, but we take care
* of those when we recurse to the RangeTblFunction node(s).
*/
foreach(lc, query->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
switch (rte->rtekind)
{
case RTE_RELATION:
add_object_address(OCLASS_CLASS, rte->relid, 0,
context->addrs);
break;
default:
break;
}
}
/*
* If the query is an INSERT or UPDATE, we should create a dependency
* on each target column, to prevent the specific target column from
* being dropped. Although we will visit the TargetEntry nodes again
* during query_tree_walker, we won't have enough context to do this
* conveniently, so do it here.
*/
if (query->commandType == CMD_INSERT ||
query->commandType == CMD_UPDATE)
{
RangeTblEntry *rte;
if (query->resultRelation <= 0 ||
query->resultRelation > list_length(query->rtable))
elog(ERROR, "invalid resultRelation %d",
query->resultRelation);
rte = rt_fetch(query->resultRelation, query->rtable);
if (rte->rtekind == RTE_RELATION)
{
foreach(lc, query->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
if (tle->resjunk)
continue; /* ignore junk tlist items */
add_object_address(OCLASS_CLASS, rte->relid, tle->resno,
context->addrs);
}
}
}
/*
* Add dependencies on constraints listed in query's constraintDeps
*/
foreach(lc, query->constraintDeps)
{
add_object_address(OCLASS_CONSTRAINT, lfirst_oid(lc), 0,
context->addrs);
}
/* 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->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 */
}
else if (IsA(node, RangeTblFunction))
{
RangeTblFunction *rtfunc = (RangeTblFunction *) node;
ListCell *ct;
/*
* Add refs for any datatypes and collations used in a column
* definition list for a RECORD function. (For other cases, it should
* be enough to depend on the function itself.)
*/
foreach(ct, rtfunc->funccoltypes)
{
add_object_address(OCLASS_TYPE, lfirst_oid(ct), 0,
context->addrs);
}
foreach(ct, rtfunc->funccolcollations)
{
Oid collid = lfirst_oid(ct);
if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
add_object_address(OCLASS_COLLATION, collid, 0,
context->addrs);
}
}
else if (IsA(node, TableSampleClause))
{
TableSampleClause *tsc = (TableSampleClause *) node;
add_object_address(OCLASS_PROC, tsc->tsmhandler, 0,
context->addrs);
/* fall through to examine arguments */
}
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;
/*
* Primary sort key is OID descending. Most of the time, this will result
* in putting newer objects before older ones, which is likely to be the
* right order to delete in.
*/
if (obja->objectId > objb->objectId)
return -1;
if (obja->objectId < objb->objectId)
return 1;
/*
* Next sort on catalog ID, in case identical OIDs appear in different
* catalogs. Sort direction is pretty arbitrary here.
*/
if (obja->classId < objb->classId)
return -1;
if (obja->classId > objb->classId)
return 1;
/*
* Last, sort on object subId.
*
* We sort the subId as an unsigned int so that 0 (the whole object) will
* come first. This is essential for eliminate_duplicate_dependencies,
* and is also the best order for findDependentObjects.
*/
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;
/*
* Make sure object_classes is kept up to date with the ObjectClass enum.
*/
StaticAssertStmt(lengthof(object_classes) == LAST_OCLASS + 1,
"object_classes[] must cover all ObjectClasses");
/* 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)
{
bool result = false;
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;
result = true;
}
else 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 subobject, so report that we
* found the subobject in the array. But don't plaster its
* flags on the whole object.
*/
result = true;
}
else if (object->objectSubId == 0)
{
/*
* We get here if we find a need to delete a whole table after
* having already decided to drop one of its columns. We
* can't report that the whole object is in the array, but we
* should mark the subobject with the whole object's flags.
*
* It might seem attractive to physically delete the column's
* array entry, or at least mark it as no longer needing
* separate deletion. But that could lead to, e.g., dropping
* the column's datatype before we drop the table, which does
* not seem like a good idea. This is a very rare situation
* in practice, so we just take the hit of doing a separate
* DROP COLUMN action even though we know we're gonna delete
* the table later.
*
* What we can do, though, is mark this as a subobject so that
* we don't report it separately, which is confusing because
* it's unpredictable whether it happens or not. But do so
* only if flags != 0 (flags == 0 is a read-only probe).
*
* Because there could be other subobjects of this object in
* the array, this case means we always have to loop through
* the whole array; we cannot exit early on a match.
*/
ObjectAddressExtra *thisextra = addrs->extras + i;
if (flags)
thisextra->flags |= (flags | DEPFLAG_SUBOBJECT);
}
}
}
return result;
}
/*
* Similar to above, except we search an ObjectAddressStack.
*/
static bool
stack_address_present_add_flags(const ObjectAddress *object,
int flags,
ObjectAddressStack *stack)
{
bool result = false;
ObjectAddressStack *stackptr;
for (stackptr = stack; stackptr; stackptr = stackptr->next)
{
const ObjectAddress *thisobj = stackptr->object;
if (object->classId == thisobj->classId &&
object->objectId == thisobj->objectId)
{
if (object->objectSubId == thisobj->objectSubId)
{
stackptr->flags |= flags;
result = true;
}
else if (thisobj->objectSubId == 0)
{
/*
* We're visiting a column with whole table already on stack.
* As in object_address_present_add_flags(), we can skip
* further processing of the subobject, but we don't want to
* propagate flags for the subobject to the whole object.
*/
result = true;
}
else if (object->objectSubId == 0)
{
/*
* We're visiting a table with column already on stack. As in
* object_address_present_add_flags(), we should propagate
* flags for the whole object to each of its subobjects.
*/
if (flags)
stackptr->flags |= (flags | DEPFLAG_SUBOBJECT);
}
}
}
return result;
}
/*
* 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);
}
/*
* Sort the items in an ObjectAddresses array.
*
* The major sort key is OID-descending, so that newer objects will be listed
* first in most cases. This is primarily useful for ensuring stable outputs
* from regression tests; it's not recommended if the order of the objects is
* determined by user input, such as the order of targets in a DROP command.
*/
void
sort_object_addresses(ObjectAddresses *addrs)
{
if (addrs->numrefs > 1)
qsort((void *) addrs->refs, addrs->numrefs,
sizeof(ObjectAddress),
object_address_comparator);
}
/*
* 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)
{
/* only pg_class entries can have nonzero objectSubId */
if (object->classId != RelationRelationId &&
object->objectSubId != 0)
elog(ERROR, "invalid non-zero objectSubId for object class %u",
object->classId);
switch (object->classId)
{
case RelationRelationId:
/* caller must check objectSubId */
return OCLASS_CLASS;
case ProcedureRelationId:
return OCLASS_PROC;
case TypeRelationId:
return OCLASS_TYPE;
case CastRelationId:
return OCLASS_CAST;
case CollationRelationId:
return OCLASS_COLLATION;
case ConstraintRelationId:
return OCLASS_CONSTRAINT;
case ConversionRelationId:
return OCLASS_CONVERSION;
case AttrDefaultRelationId:
return OCLASS_DEFAULT;
case LanguageRelationId:
return OCLASS_LANGUAGE;
case LargeObjectRelationId:
return OCLASS_LARGEOBJECT;
case OperatorRelationId:
return OCLASS_OPERATOR;
case OperatorClassRelationId:
return OCLASS_OPCLASS;
case OperatorFamilyRelationId:
return OCLASS_OPFAMILY;
case AccessMethodRelationId:
return OCLASS_AM;
case AccessMethodOperatorRelationId:
return OCLASS_AMOP;
case AccessMethodProcedureRelationId:
return OCLASS_AMPROC;
case RewriteRelationId:
return OCLASS_REWRITE;
case TriggerRelationId:
return OCLASS_TRIGGER;
case NamespaceRelationId:
return OCLASS_SCHEMA;
case StatisticExtRelationId:
return OCLASS_STATISTIC_EXT;
case TSParserRelationId:
return OCLASS_TSPARSER;
case TSDictionaryRelationId:
return OCLASS_TSDICT;
case TSTemplateRelationId:
return OCLASS_TSTEMPLATE;
case TSConfigRelationId:
return OCLASS_TSCONFIG;
case AuthIdRelationId:
return OCLASS_ROLE;
case DatabaseRelationId:
return OCLASS_DATABASE;
case TableSpaceRelationId:
return OCLASS_TBLSPACE;
case ForeignDataWrapperRelationId:
return OCLASS_FDW;
case ForeignServerRelationId:
return OCLASS_FOREIGN_SERVER;
case UserMappingRelationId:
return OCLASS_USER_MAPPING;
case DefaultAclRelationId:
return OCLASS_DEFACL;
case ExtensionRelationId:
return OCLASS_EXTENSION;
case EventTriggerRelationId:
return OCLASS_EVENT_TRIGGER;
case ExtprotocolRelationId:
Assert(object->objectSubId == 0);
return OCLASS_EXTPROTOCOL;
case PolicyRelationId:
return OCLASS_POLICY;
case PublicationRelationId:
return OCLASS_PUBLICATION;
case PublicationRelRelationId:
return OCLASS_PUBLICATION_REL;
case SubscriptionRelationId:
return OCLASS_SUBSCRIPTION;
case TransformRelationId:
return OCLASS_TRANSFORM;
}
/* shouldn't get here */
elog(ERROR, "unrecognized object class: %u", object->classId);
return OCLASS_CLASS; /* keep compiler quiet */
}
/* check if there are dependencies on the objects provides, error out if exists*/
void
checkDependencies(const ObjectAddresses *objects,
const char *msg,
const char *hint)
{
Relation depRel;
ObjectAddresses *targetObjects;
StringInfoData clientdetail;
bool ok = true;
int i;
int numReportedClient = 0;
/*
* 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);
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, 0);
findDependentObjects(thisobj,
DEPFLAG_ORIGINAL,
0,
NULL, /* empty stack */
targetObjects,
objects,
&depRel);
}
/*
* 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);
for (i = targetObjects->numrefs - 1; i >= 0; i--)
{
const ObjectAddress *obj = &targetObjects->refs[i];
const ObjectAddressExtra *extra = &targetObjects->extras[i];
char *otherDesc;
char *objDesc;
if (extra->flags & (DEPFLAG_ORIGINAL |
DEPFLAG_AUTO |
DEPFLAG_INTERNAL |
DEPFLAG_EXTENSION))
continue;
objDesc = getObjectDescription(obj);
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++;
}
pfree(objDesc);
pfree(otherDesc);
ok = false;
}
if (!ok)
ereport(ERROR,
(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
errmsg("%s", msg),
errdetail("%s", clientdetail.data),
errhint("%s", hint)));
pfree(clientdetail.data);
/* And clean up */
free_object_addresses(targetObjects);
heap_close(depRel, RowExclusiveLock);
}
/*
* delete initial ACL for extension objects
*/
static void
DeleteInitPrivs(const ObjectAddress *object)
{
Relation relation;
ScanKeyData key[3];
SysScanDesc scan;
HeapTuple oldtuple;
relation = table_open(InitPrivsRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_init_privs_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&key[1],
Anum_pg_init_privs_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
ScanKeyInit(&key[2],
Anum_pg_init_privs_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(object->objectSubId));
scan = systable_beginscan(relation, InitPrivsObjIndexId, true,
NULL, 3, key);
while (HeapTupleIsValid(oldtuple = systable_getnext(scan)))
CatalogTupleDelete(relation, &oldtuple->t_self);
systable_endscan(scan);
table_close(relation, RowExclusiveLock);
}
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