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This adds a new ON CONFLICT action DO SELECT [FOR UPDATE/SHARE], which returns the pre-existing rows when conflicts are detected. The INSERT statement must have a RETURNING clause, when DO SELECT is specified. The optional FOR UPDATE/SHARE clause allows the rows to be locked before they are are returned. As with a DO UPDATE conflict action, an optional WHERE clause may be used to prevent rows from being selected for return (but as with a DO UPDATE action, rows filtered out by the WHERE clause are still locked). Bumps catversion as stored rules change. Author: Andreas Karlsson <andreas@proxel.se> Author: Marko Tiikkaja <marko@joh.to> Author: Viktor Holmberg <v@viktorh.net> Reviewed-by: Joel Jacobson <joel@compiler.org> Reviewed-by: Kirill Reshke <reshkekirill@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Jian He <jian.universality@gmail.com> Discussion: https://postgr.es/m/d631b406-13b7-433e-8c0b-c6040c4b4663@Spark Discussion: https://postgr.es/m/5fca222d-62ae-4a2f-9fcb-0eca56277094@Spark Discussion: https://postgr.es/m/2b5db2e6-8ece-44d0-9890-f256fdca9f7e@proxel.se Discussion: https://postgr.es/m/CAL9smLCdV-v3KgOJX3mU19FYK82N7yzqJj2HAwWX70E=P98kgQ@mail.gmail.com
62 lines
1.9 KiB
C
62 lines
1.9 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) 2014-2026, 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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* and ON CONFLICT DO SELECT */
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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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