postgresql/src/include/catalog/dependency.h

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/*-------------------------------------------------------------------------
*
* dependency.h
* Routines to support inter-object dependencies.
*
*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
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* src/include/catalog/dependency.h
*
*-------------------------------------------------------------------------
*/
#ifndef DEPENDENCY_H
#define DEPENDENCY_H
#include "catalog/objectaddress.h"
/*
* Precise semantics of a dependency relationship are specified by the
* DependencyType code (which is stored in a "char" field in pg_depend,
* so we assign ASCII-code values to the enumeration members).
*
* In all cases, a dependency relationship indicates that the referenced
* object may not be dropped without also dropping the dependent object.
* However, there are several subflavors:
*
* DEPENDENCY_NORMAL ('n'): normal relationship between separately-created
* objects. The dependent object may be dropped without affecting the
* referenced object. The referenced object may only be dropped by
* specifying CASCADE, in which case the dependent object is dropped too.
* Example: a table column has a normal dependency on its datatype.
*
* DEPENDENCY_AUTO ('a'): the dependent object can be dropped separately
* from the referenced object, and should be automatically dropped
* (regardless of RESTRICT or CASCADE mode) if the referenced object
* is dropped.
* Example: a named constraint on a table is made auto-dependent on
* the table, so that it will go away if the table is dropped.
*
* DEPENDENCY_INTERNAL ('i'): the dependent object was created as part
* of creation of the referenced object, and is really just a part of
* its internal implementation. A DROP of the dependent object will be
* disallowed outright (we'll tell the user to issue a DROP against the
* referenced object, instead). A DROP of the referenced object will be
* propagated through to drop the dependent object whether CASCADE is
* specified or not.
* Example: a trigger that's created to enforce a foreign-key constraint
* is made internally dependent on the constraint's pg_constraint entry.
*
* DEPENDENCY_EXTENSION ('e'): the dependent object is a member of the
* extension that is the referenced object. The dependent object can be
* dropped only via DROP EXTENSION on the referenced object. Functionally
* this dependency type acts the same as an internal dependency, but it's
* kept separate for clarity and to simplify pg_dump.
*
* DEPENDENCY_AUTO_EXTENSION ('x'): the dependent object is not a member
* of the extension that is the referenced object (and so should not be
* ignored by pg_dump), but cannot function without the extension and
* should be dropped when the extension itself is. The dependent object
* may be dropped on its own as well.
*
* DEPENDENCY_PIN ('p'): there is no dependent object; this type of entry
* is a signal that the system itself depends on the referenced object,
* and so that object must never be deleted. Entries of this type are
* created only during initdb. The fields for the dependent object
* contain zeroes.
*
* Other dependency flavors may be needed in future.
*/
typedef enum DependencyType
{
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DEPENDENCY_NORMAL = 'n',
DEPENDENCY_AUTO = 'a',
DEPENDENCY_INTERNAL = 'i',
DEPENDENCY_EXTENSION = 'e',
DEPENDENCY_AUTO_EXTENSION = 'x',
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DEPENDENCY_PIN = 'p'
} DependencyType;
/*
* There is also a SharedDependencyType enum type that determines the exact
* semantics of an entry in pg_shdepend. Just like regular dependency entries,
* any pg_shdepend entry means that the referenced object cannot be dropped
* unless the dependent object is dropped at the same time. There are some
* additional rules however:
*
* (a) For a SHARED_DEPENDENCY_PIN entry, there is no dependent object --
* rather, the referenced object is an essential part of the system. This
* applies to the initdb-created superuser. Entries of this type are only
* created by initdb; objects in this category don't need further pg_shdepend
* entries if more objects come to depend on them.
*
* (b) a SHARED_DEPENDENCY_OWNER entry means that the referenced object is
* the role owning the dependent object. The referenced object must be
* a pg_authid entry.
*
* (c) a SHARED_DEPENDENCY_ACL entry means that the referenced object is
* a role mentioned in the ACL field of the dependent object. The referenced
* object must be a pg_authid entry. (SHARED_DEPENDENCY_ACL entries are not
* created for the owner of an object; hence two objects may be linked by
* one or the other, but not both, of these dependency types.)
*
* (d) a SHARED_DEPENDENCY_POLICY entry means that the referenced object is
* a role mentioned in a policy object. The referenced object must be a
* pg_authid entry.
*
* SHARED_DEPENDENCY_INVALID is a value used as a parameter in internal
* routines, and is not valid in the catalog itself.
*/
typedef enum SharedDependencyType
{
SHARED_DEPENDENCY_PIN = 'p',
SHARED_DEPENDENCY_OWNER = 'o',
SHARED_DEPENDENCY_ACL = 'a',
SHARED_DEPENDENCY_POLICY = 'r',
SHARED_DEPENDENCY_INVALID = 0
} SharedDependencyType;
/* expansible list of ObjectAddresses (private in dependency.c) */
typedef struct ObjectAddresses ObjectAddresses;
/*
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* This enum covers all system catalogs whose OIDs can appear in
* pg_depend.classId or pg_shdepend.classId. Keep object_classes[] in sync.
*/
typedef enum ObjectClass
{
OCLASS_CLASS, /* pg_class */
OCLASS_PROC, /* pg_proc */
OCLASS_TYPE, /* pg_type */
OCLASS_CAST, /* pg_cast */
OCLASS_COLLATION, /* pg_collation */
OCLASS_CONSTRAINT, /* pg_constraint */
OCLASS_CONVERSION, /* pg_conversion */
OCLASS_DEFAULT, /* pg_attrdef */
OCLASS_LANGUAGE, /* pg_language */
OCLASS_LARGEOBJECT, /* pg_largeobject */
OCLASS_OPERATOR, /* pg_operator */
OCLASS_OPCLASS, /* pg_opclass */
OCLASS_OPFAMILY, /* pg_opfamily */
OCLASS_AM, /* pg_am */
OCLASS_AMOP, /* pg_amop */
OCLASS_AMPROC, /* pg_amproc */
OCLASS_REWRITE, /* pg_rewrite */
OCLASS_TRIGGER, /* pg_trigger */
OCLASS_SCHEMA, /* pg_namespace */
OCLASS_TSPARSER, /* pg_ts_parser */
OCLASS_TSDICT, /* pg_ts_dict */
OCLASS_TSTEMPLATE, /* pg_ts_template */
OCLASS_TSCONFIG, /* pg_ts_config */
OCLASS_ROLE, /* pg_authid */
OCLASS_DATABASE, /* pg_database */
OCLASS_TBLSPACE, /* pg_tablespace */
OCLASS_FDW, /* pg_foreign_data_wrapper */
OCLASS_FOREIGN_SERVER, /* pg_foreign_server */
OCLASS_USER_MAPPING, /* pg_user_mapping */
OCLASS_DEFACL, /* pg_default_acl */
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OCLASS_EXTENSION, /* pg_extension */
OCLASS_EVENT_TRIGGER, /* pg_event_trigger */
OCLASS_POLICY, /* pg_policy */
OCLASS_PUBLICATION, /* pg_publication */
OCLASS_PUBLICATION_REL, /* pg_publication_rel */
OCLASS_SUBSCRIPTION, /* pg_subscription */
OCLASS_TRANSFORM /* pg_transform */
} ObjectClass;
#define LAST_OCLASS OCLASS_TRANSFORM
Delete deleteWhatDependsOn() in favor of more performDeletion() flag bits. deleteWhatDependsOn() had grown an uncomfortably large number of assumptions about what it's used for. There are actually only two minor differences between what it does and what a regular performDeletion() call can do, so let's invent additional bits in performDeletion's existing flags argument that specify those behaviors, and get rid of deleteWhatDependsOn() as such. (We'd probably have done it this way from the start, except that performDeletion didn't originally have a flags argument, IIRC.) Also, add a SKIP_EXTENSIONS flag bit that prevents ever recursing to an extension, and use that when dropping temporary objects at session end. This provides a more general solution to the problem addressed in a hacky way in commit 08dd23cec: if an extension script creates temp objects and forgets to remove them again, the whole extension went away when its contained temp objects were deleted. The previous solution only covered temp relations, but this solves it for all object types. These changes require minor additions in dependency.c to pass the flags to subroutines that previously didn't get them, but it's still a net savings of code, and it seems cleaner than before. Having done this, revert the special-case code added in 08dd23cec that prevented addition of pg_depend records for temp table extension membership, because that caused its own oddities: dropping an extension that had created such a table didn't automatically remove the table, leading to a failure if the table had another dependency on the extension (such as use of an extension data type), or to a duplicate-name failure if you then tried to recreate the extension. But we keep the part that prevents the pg_temp_nnn schema from becoming an extension member; we never want that to happen. Add a regression test case covering these behaviors. Although this fixes some arguable bugs, we've heard few field complaints, and any such problems are easily worked around by explicitly dropping temp objects at the end of extension scripts (which seems like good practice anyway). So I won't risk a back-patch. Discussion: https://postgr.es/m/e51f4311-f483-4dd0-1ccc-abec3c405110@BlueTreble.com
2016-12-02 20:57:35 +01:00
/* flag bits for performDeletion/performMultipleDeletions: */
#define PERFORM_DELETION_INTERNAL 0x0001 /* internal action */
#define PERFORM_DELETION_CONCURRENTLY 0x0002 /* concurrent drop */
#define PERFORM_DELETION_QUIETLY 0x0004 /* suppress notices */
#define PERFORM_DELETION_SKIP_ORIGINAL 0x0008 /* keep original obj */
#define PERFORM_DELETION_SKIP_EXTENSIONS 0x0010 /* keep extensions */
Delete deleteWhatDependsOn() in favor of more performDeletion() flag bits. deleteWhatDependsOn() had grown an uncomfortably large number of assumptions about what it's used for. There are actually only two minor differences between what it does and what a regular performDeletion() call can do, so let's invent additional bits in performDeletion's existing flags argument that specify those behaviors, and get rid of deleteWhatDependsOn() as such. (We'd probably have done it this way from the start, except that performDeletion didn't originally have a flags argument, IIRC.) Also, add a SKIP_EXTENSIONS flag bit that prevents ever recursing to an extension, and use that when dropping temporary objects at session end. This provides a more general solution to the problem addressed in a hacky way in commit 08dd23cec: if an extension script creates temp objects and forgets to remove them again, the whole extension went away when its contained temp objects were deleted. The previous solution only covered temp relations, but this solves it for all object types. These changes require minor additions in dependency.c to pass the flags to subroutines that previously didn't get them, but it's still a net savings of code, and it seems cleaner than before. Having done this, revert the special-case code added in 08dd23cec that prevented addition of pg_depend records for temp table extension membership, because that caused its own oddities: dropping an extension that had created such a table didn't automatically remove the table, leading to a failure if the table had another dependency on the extension (such as use of an extension data type), or to a duplicate-name failure if you then tried to recreate the extension. But we keep the part that prevents the pg_temp_nnn schema from becoming an extension member; we never want that to happen. Add a regression test case covering these behaviors. Although this fixes some arguable bugs, we've heard few field complaints, and any such problems are easily worked around by explicitly dropping temp objects at the end of extension scripts (which seems like good practice anyway). So I won't risk a back-patch. Discussion: https://postgr.es/m/e51f4311-f483-4dd0-1ccc-abec3c405110@BlueTreble.com
2016-12-02 20:57:35 +01:00
/* in dependency.c */
extern void performDeletion(const ObjectAddress *object,
DropBehavior behavior, int flags);
extern void performMultipleDeletions(const ObjectAddresses *objects,
DropBehavior behavior, int flags);
extern void recordDependencyOnExpr(const ObjectAddress *depender,
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Node *expr, List *rtable,
DependencyType behavior);
extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
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Node *expr, Oid relId,
DependencyType behavior,
Implement table partitioning. Table partitioning is like table inheritance and reuses much of the existing infrastructure, but there are some important differences. The parent is called a partitioned table and is always empty; it may not have indexes or non-inherited constraints, since those make no sense for a relation with no data of its own. The children are called partitions and contain all of the actual data. Each partition has an implicit partitioning constraint. Multiple inheritance is not allowed, and partitioning and inheritance can't be mixed. Partitions can't have extra columns and may not allow nulls unless the parent does. Tuples inserted into the parent are automatically routed to the correct partition, so tuple-routing ON INSERT triggers are not needed. Tuple routing isn't yet supported for partitions which are foreign tables, and it doesn't handle updates that cross partition boundaries. Currently, tables can be range-partitioned or list-partitioned. List partitioning is limited to a single column, but range partitioning can involve multiple columns. A partitioning "column" can be an expression. Because table partitioning is less general than table inheritance, it is hoped that it will be easier to reason about properties of partitions, and therefore that this will serve as a better foundation for a variety of possible optimizations, including query planner optimizations. The tuple routing based which this patch does based on the implicit partitioning constraints is an example of this, but it seems likely that many other useful optimizations are also possible. Amit Langote, reviewed and tested by Robert Haas, Ashutosh Bapat, Amit Kapila, Rajkumar Raghuwanshi, Corey Huinker, Jaime Casanova, Rushabh Lathia, Erik Rijkers, among others. Minor revisions by me.
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DependencyType self_behavior,
bool ignore_self);
extern ObjectClass getObjectClass(const ObjectAddress *object);
extern ObjectAddresses *new_object_addresses(void);
extern void add_exact_object_address(const ObjectAddress *object,
ObjectAddresses *addrs);
extern bool object_address_present(const ObjectAddress *object,
const ObjectAddresses *addrs);
extern void record_object_address_dependencies(const ObjectAddress *depender,
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ObjectAddresses *referenced,
DependencyType behavior);
extern void free_object_addresses(ObjectAddresses *addrs);
/* in pg_depend.c */
extern void recordDependencyOn(const ObjectAddress *depender,
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const ObjectAddress *referenced,
DependencyType behavior);
extern void recordMultipleDependencies(const ObjectAddress *depender,
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const ObjectAddress *referenced,
int nreferenced,
DependencyType behavior);
extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
bool isReplace);
extern long deleteDependencyRecordsFor(Oid classId, Oid objectId,
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bool skipExtensionDeps);
extern long deleteDependencyRecordsForClass(Oid classId, Oid objectId,
Oid refclassId, char deptype);
extern long changeDependencyFor(Oid classId, Oid objectId,
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Oid refClassId, Oid oldRefObjectId,
Oid newRefObjectId);
extern Oid getExtensionOfObject(Oid classId, Oid objectId);
extern bool sequenceIsOwned(Oid seqId, Oid *tableId, int32 *colId);
extern void markSequenceUnowned(Oid seqId);
extern List *getOwnedSequences(Oid relid);
extern Oid get_constraint_index(Oid constraintId);
extern Oid get_index_constraint(Oid indexId);
/* in pg_shdepend.c */
extern void recordSharedDependencyOn(ObjectAddress *depender,
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ObjectAddress *referenced,
SharedDependencyType deptype);
extern void deleteSharedDependencyRecordsFor(Oid classId, Oid objectId,
int32 objectSubId);
extern void recordDependencyOnOwner(Oid classId, Oid objectId, Oid owner);
extern void changeDependencyOnOwner(Oid classId, Oid objectId,
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Oid newOwnerId);
extern void updateAclDependencies(Oid classId, Oid objectId, int32 objectSubId,
Oid ownerId,
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int noldmembers, Oid *oldmembers,
int nnewmembers, Oid *newmembers);
extern bool checkSharedDependencies(Oid classId, Oid objectId,
char **detail_msg, char **detail_log_msg);
extern void shdepLockAndCheckObject(Oid classId, Oid objectId);
extern void copyTemplateDependencies(Oid templateDbId, Oid newDbId);
extern void dropDatabaseDependencies(Oid databaseId);
extern void shdepDropOwned(List *relids, DropBehavior behavior);
extern void shdepReassignOwned(List *relids, Oid newrole);
#endif /* DEPENDENCY_H */