postgresql/src/include/catalog/index.h

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/*-------------------------------------------------------------------------
*
* index.h
* prototypes for catalog/index.c.
*
*
* Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
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* src/include/catalog/index.h
*
*-------------------------------------------------------------------------
*/
#ifndef INDEX_H
#define INDEX_H
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#include "nodes/execnodes.h"
#define DEFAULT_INDEX_TYPE "btree"
/* Typedef for callback function for IndexBuildHeapScan */
typedef void (*IndexBuildCallback) (Relation index,
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HeapTuple htup,
Datum *values,
bool *isnull,
bool tupleIsAlive,
void *state);
Fix assorted bugs in CREATE/DROP INDEX CONCURRENTLY. Commit 8cb53654dbdb4c386369eb988062d0bbb6de725e, which introduced DROP INDEX CONCURRENTLY, managed to break CREATE INDEX CONCURRENTLY via a poor choice of catalog state representation. The pg_index state for an index that's reached the final pre-drop stage was the same as the state for an index just created by CREATE INDEX CONCURRENTLY. This meant that the (necessary) change to make RelationGetIndexList ignore about-to-die indexes also made it ignore freshly-created indexes; which is catastrophic because the latter do need to be considered in HOT-safety decisions. Failure to do so leads to incorrect index entries and subsequently wrong results from queries depending on the concurrently-created index. To fix, add an additional boolean column "indislive" to pg_index, so that the freshly-created and about-to-die states can be distinguished. (This change obviously is only possible in HEAD. This patch will need to be back-patched, but in 9.2 we'll use a kluge consisting of overloading the formerly-impossible state of indisvalid = true and indisready = false.) In addition, change CREATE/DROP INDEX CONCURRENTLY so that the pg_index flag changes they make without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. This is a pre-existing bug in CREATE INDEX CONCURRENTLY, which was copied into the DROP code. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. In addition, do some code and docs review for DROP INDEX CONCURRENTLY; some cosmetic code cleanup but mostly addition and revision of comments. This will need to be back-patched, but in a noticeably different form, so I'm committing it to HEAD before working on the back-patch. Problem reported by Amit Kapila, diagnosis by Pavan Deolassee, fix by Tom Lane and Andres Freund.
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/* Action code for index_set_state_flags */
typedef enum
{
INDEX_CREATE_SET_READY,
INDEX_CREATE_SET_VALID,
INDEX_DROP_CLEAR_VALID,
INDEX_DROP_SET_DEAD
} IndexStateFlagsAction;
extern void index_check_primary_key(Relation heapRel,
IndexInfo *indexInfo,
bool is_alter_table);
extern Oid index_create(Relation heapRelation,
const char *indexRelationName,
Oid indexRelationId,
Oid relFileNode,
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IndexInfo *indexInfo,
List *indexColNames,
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Oid accessMethodObjectId,
Oid tableSpaceId,
Oid *collationObjectId,
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Oid *classObjectId,
int16 *coloptions,
Datum reloptions,
bool isprimary,
bool isconstraint,
bool deferrable,
bool initdeferred,
bool allow_system_table_mods,
bool skip_build,
bool concurrent,
bool is_internal,
bool if_not_exists);
extern void index_constraint_create(Relation heapRelation,
Oid indexRelationId,
IndexInfo *indexInfo,
const char *constraintName,
char constraintType,
bool deferrable,
bool initdeferred,
bool mark_as_primary,
bool update_pgindex,
bool remove_old_dependencies,
bool allow_system_table_mods,
bool is_internal);
extern void index_drop(Oid indexId, bool concurrent);
extern IndexInfo *BuildIndexInfo(Relation index);
extern void FormIndexDatum(IndexInfo *indexInfo,
TupleTableSlot *slot,
EState *estate,
Datum *values,
bool *isnull);
extern void index_build(Relation heapRelation,
Relation indexRelation,
IndexInfo *indexInfo,
bool isprimary,
bool isreindex);
extern double IndexBuildHeapScan(Relation heapRelation,
Relation indexRelation,
IndexInfo *indexInfo,
bool allow_sync,
IndexBuildCallback callback,
void *callback_state);
extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
Fix assorted bugs in CREATE/DROP INDEX CONCURRENTLY. Commit 8cb53654dbdb4c386369eb988062d0bbb6de725e, which introduced DROP INDEX CONCURRENTLY, managed to break CREATE INDEX CONCURRENTLY via a poor choice of catalog state representation. The pg_index state for an index that's reached the final pre-drop stage was the same as the state for an index just created by CREATE INDEX CONCURRENTLY. This meant that the (necessary) change to make RelationGetIndexList ignore about-to-die indexes also made it ignore freshly-created indexes; which is catastrophic because the latter do need to be considered in HOT-safety decisions. Failure to do so leads to incorrect index entries and subsequently wrong results from queries depending on the concurrently-created index. To fix, add an additional boolean column "indislive" to pg_index, so that the freshly-created and about-to-die states can be distinguished. (This change obviously is only possible in HEAD. This patch will need to be back-patched, but in 9.2 we'll use a kluge consisting of overloading the formerly-impossible state of indisvalid = true and indisready = false.) In addition, change CREATE/DROP INDEX CONCURRENTLY so that the pg_index flag changes they make without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. This is a pre-existing bug in CREATE INDEX CONCURRENTLY, which was copied into the DROP code. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. In addition, do some code and docs review for DROP INDEX CONCURRENTLY; some cosmetic code cleanup but mostly addition and revision of comments. This will need to be back-patched, but in a noticeably different form, so I'm committing it to HEAD before working on the back-patch. Problem reported by Amit Kapila, diagnosis by Pavan Deolassee, fix by Tom Lane and Andres Freund.
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extern void index_set_state_flags(Oid indexId, IndexStateFlagsAction action);
extern void reindex_index(Oid indexId, bool skip_constraint_checks);
/* Flag bits for reindex_relation(): */
#define REINDEX_REL_PROCESS_TOAST 0x01
#define REINDEX_REL_SUPPRESS_INDEX_USE 0x02
#define REINDEX_REL_CHECK_CONSTRAINTS 0x04
extern bool reindex_relation(Oid relid, int flags);
extern bool ReindexIsProcessingHeap(Oid heapOid);
extern bool ReindexIsProcessingIndex(Oid indexOid);
extern Oid IndexGetRelation(Oid indexId, bool missing_ok);
#endif /* INDEX_H */