62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* lockoptions.h
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* Common header for some locking-related declarations.
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*
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*
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* Copyright (c) 2014-2024, PostgreSQL Global Development Group
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*
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* src/include/nodes/lockoptions.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LOCKOPTIONS_H
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#define LOCKOPTIONS_H
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/*
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* This enum represents the different strengths of FOR UPDATE/SHARE clauses.
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* The ordering here is important, because the highest numerical value takes
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* precedence when a RTE is specified multiple ways. See applyLockingClause.
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*/
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typedef enum LockClauseStrength
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{
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LCS_NONE, /* no such clause - only used in PlanRowMark */
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LCS_FORKEYSHARE, /* FOR KEY SHARE */
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LCS_FORSHARE, /* FOR SHARE */
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LCS_FORNOKEYUPDATE, /* FOR NO KEY UPDATE */
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LCS_FORUPDATE, /* FOR UPDATE */
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} LockClauseStrength;
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/*
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* This enum controls how to deal with rows being locked by FOR UPDATE/SHARE
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* clauses (i.e., it represents the NOWAIT and SKIP LOCKED options).
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* The ordering here is important, because the highest numerical value takes
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* precedence when a RTE is specified multiple ways. See applyLockingClause.
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*/
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typedef enum LockWaitPolicy
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{
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/* Wait for the lock to become available (default behavior) */
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LockWaitBlock,
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/* Skip rows that can't be locked (SKIP LOCKED) */
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LockWaitSkip,
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/* Raise an error if a row cannot be locked (NOWAIT) */
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LockWaitError,
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} LockWaitPolicy;
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/*
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* Possible lock modes for a tuple.
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*/
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typedef enum LockTupleMode
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{
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/* SELECT FOR KEY SHARE */
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LockTupleKeyShare,
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/* SELECT FOR SHARE */
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LockTupleShare,
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/* SELECT FOR NO KEY UPDATE, and UPDATEs that don't modify key columns */
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LockTupleNoKeyExclusive,
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/* SELECT FOR UPDATE, UPDATEs that modify key columns, and DELETE */
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LockTupleExclusive,
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} LockTupleMode;
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#endif /* LOCKOPTIONS_H */
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