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e2eefb97e3
Commit5b562644feadded a comment that SetRelationHasSubclass() callers must hold this lock. When commit17f206fbc8extended use of this column to partitioned indexes, it didn't take the lock. As the latter commit message mentioned, we currently never reset a partitioned index to relhassubclass=f. That largely avoids harm from the lock omission. The cause for fixing this now is to unblock introducing a rule about locks required to heap_update() a pg_class row. This might cause more deadlocks. It gives minor user-visible benefits: - If an ALTER INDEX SET TABLESPACE runs concurrently with ALTER TABLE ATTACH PARTITION or CREATE PARTITION OF, one transaction blocks instead of failing with "tuple concurrently updated". (Many cases of DDL concurrency still fail that way.) - Match ALTER INDEX ATTACH PARTITION in choosing to lock the index. While not user-visible today, we'll need this if we ever make something set the flag to false for a partitioned index, like ANALYZE does today for tables. Back-patch to v12 (all supported versions), the plan for the commit relying on the new rule. In back branches, add LockOrStrongerHeldByMe() instead of adding a LockHeldByMe() parameter. Reviewed (in an earlier version) by Robert Haas. Discussion: https://postgr.es/m/20240611024525.9f.nmisch@google.com
119 lines
4.7 KiB
C
119 lines
4.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* lmgr.h
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* POSTGRES lock manager definitions.
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*
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*
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* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/lmgr.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LMGR_H
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#define LMGR_H
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#include "lib/stringinfo.h"
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#include "storage/itemptr.h"
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#include "storage/lock.h"
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#include "utils/rel.h"
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/* XactLockTableWait operations */
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typedef enum XLTW_Oper
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{
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XLTW_None,
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XLTW_Update,
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XLTW_Delete,
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XLTW_Lock,
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XLTW_LockUpdated,
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XLTW_InsertIndex,
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XLTW_InsertIndexUnique,
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XLTW_FetchUpdated,
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XLTW_RecheckExclusionConstr
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} XLTW_Oper;
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extern void RelationInitLockInfo(Relation relation);
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/* Lock a relation */
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extern void LockRelationOid(Oid relid, LOCKMODE lockmode);
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extern bool ConditionalLockRelationOid(Oid relid, LOCKMODE lockmode);
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extern void UnlockRelationId(LockRelId *relid, LOCKMODE lockmode);
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extern void UnlockRelationOid(Oid relid, LOCKMODE lockmode);
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extern void LockRelation(Relation relation, LOCKMODE lockmode);
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extern bool ConditionalLockRelation(Relation relation, LOCKMODE lockmode);
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extern void UnlockRelation(Relation relation, LOCKMODE lockmode);
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extern bool CheckRelationLockedByMe(Relation relation, LOCKMODE lockmode,
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bool orstronger);
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extern bool CheckRelationOidLockedByMe(Oid relid, LOCKMODE lockmode,
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bool orstronger);
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extern bool LockHasWaitersRelation(Relation relation, LOCKMODE lockmode);
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extern void LockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
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extern void UnlockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
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/* Lock a relation for extension */
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extern void LockRelationForExtension(Relation relation, LOCKMODE lockmode);
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extern void UnlockRelationForExtension(Relation relation, LOCKMODE lockmode);
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extern bool ConditionalLockRelationForExtension(Relation relation,
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LOCKMODE lockmode);
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extern int RelationExtensionLockWaiterCount(Relation relation);
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/* Lock to recompute pg_database.datfrozenxid in the current database */
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extern void LockDatabaseFrozenIds(LOCKMODE lockmode);
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/* Lock a page (currently only used within indexes) */
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extern void LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
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extern bool ConditionalLockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
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extern void UnlockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
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/* Lock a tuple (see heap_lock_tuple before assuming you understand this) */
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extern void LockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
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extern bool ConditionalLockTuple(Relation relation, ItemPointer tid,
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LOCKMODE lockmode);
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extern void UnlockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
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/* Lock an XID (used to wait for a transaction to finish) */
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extern void XactLockTableInsert(TransactionId xid);
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extern void XactLockTableDelete(TransactionId xid);
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extern void XactLockTableWait(TransactionId xid, Relation rel,
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ItemPointer ctid, XLTW_Oper oper);
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extern bool ConditionalXactLockTableWait(TransactionId xid);
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/* Lock VXIDs, specified by conflicting locktags */
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extern void WaitForLockers(LOCKTAG heaplocktag, LOCKMODE lockmode, bool progress);
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extern void WaitForLockersMultiple(List *locktags, LOCKMODE lockmode, bool progress);
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/* Lock an XID for tuple insertion (used to wait for an insertion to finish) */
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extern uint32 SpeculativeInsertionLockAcquire(TransactionId xid);
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extern void SpeculativeInsertionLockRelease(TransactionId xid);
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extern void SpeculativeInsertionWait(TransactionId xid, uint32 token);
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/* Lock a general object (other than a relation) of the current database */
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extern void LockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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extern bool ConditionalLockDatabaseObject(Oid classid, Oid objid,
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uint16 objsubid, LOCKMODE lockmode);
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extern void UnlockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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/* Lock a shared-across-databases object (other than a relation) */
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extern void LockSharedObject(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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extern void UnlockSharedObject(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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extern void LockSharedObjectForSession(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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extern void UnlockSharedObjectForSession(Oid classid, Oid objid, uint16 objsubid,
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LOCKMODE lockmode);
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/* Describe a locktag for error messages */
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extern void DescribeLockTag(StringInfo buf, const LOCKTAG *tag);
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extern const char *GetLockNameFromTagType(uint16 locktag_type);
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#endif /* LMGR_H */
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