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Wiki / Locks

SHARE ROW EXCLUSIVE

Conflicts with the ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE, EXCLUSIVE, and ACCESS EXCLUSIVE lock modes. This mode protects a table against concurrent data changes, and is self-exclusive so that only one session can hold it at a time. Acquired by CREATE TRIGGER and some forms of ALTER TABLE.

Reading PG 18·Select a recorded version

Compatibility

Compare different transactions holding locks on the same Table lock.

View the full compatibility matrices

Commands acquiring this mode

SQL commandObject, phase and conditions
CREATE TRIGGERLock the table that owns the trigger. Source
LOCK TABLE … IN SHARE ROW EXCLUSIVE MODERequest this table mode explicitly. Omitting IN MODE defaults to ACCESS EXCLUSIVE. Source
ALTER TABLE … ENABLE / DISABLE TRIGGEREnable or disable triggers, including the applicable USER, ALL, REPLICA and ALWAYS forms. Source
ALTER TABLE … ADD FOREIGN KEY [NOT VALID] (referencing table)Both referencing and referenced tables take SHARE ROW EXCLUSIVE. NOT VALID skips the initial data check, not this lock. Source
ALTER TABLE … ADD FOREIGN KEY [NOT VALID] (referenced table)The referenced table also takes SHARE ROW EXCLUSIVE, not merely ACCESS SHARE. Source

Other lock modes

conflicts
row-exclusive, share-update-exclusive, share, share-row-exclusive, exclusive, access-exclusive

Definition PG 18

Conflicts with the ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE, EXCLUSIVE, and ACCESS EXCLUSIVE lock modes. This mode protects a table against concurrent data changes, and is self-exclusive so that only one session can hold it at a time. Acquired by CREATE TRIGGER and some forms of ALTER TABLE.

Compare versions

Complete source facts

commands

map[label:CREATE TRIGGER note:Lock the table that owns the trigger. slug:create-trigger source:map[kind:documentation path:doc/src/sgml/mvcc.sgml revision:753057e340da8f22e57c9a409ea7a235fd6a46bd sha256:4b7bf77ee0af4b86052330ff2421d567df3604b75fe7d4f522bec84fdea87340 url:https://raw.githubusercontent.com/postgres/postgres/753057e340da8f22e57c9a409ea7a235fd6a46bd/doc/src/sgml/mvcc.sgml] source_url:https://www.postgresql.org/docs/18/explicit-locking.html variant:b9c9402ba031], map[label:LOCK TABLE … IN SHARE ROW EXCLUSIVE MODE note:Request this table mode explicitly. Omitting IN MODE defaults to ACCESS EXCLUSIVE. slug:lock source:map[kind:documentation path:doc/src/sgml/mvcc.sgml revision:753057e340da8f22e57c9a409ea7a235fd6a46bd sha256:4b7bf77ee0af4b86052330ff2421d567df3604b75fe7d4f522bec84fdea87340 url:https://raw.githubusercontent.com/postgres/postgres/753057e340da8f22e57c9a409ea7a235fd6a46bd/doc/src/sgml/mvcc.sgml] source_url:https://www.postgresql.org/docs/18/explicit-locking.html variant:60f865c101ab], map[label:ALTER TABLE … ENABLE / DISABLE TRIGGER note:Enable or disable triggers, including the applicable USER, ALL, REPLICA and ALWAYS forms. slug:alter-table source:map[kind:source path:src/backend/commands/tablecmds.c revision:753057e340da8f22e57c9a409ea7a235fd6a46bd sha256:df8817816f893e73d5648fea169e222ba33320e5b24bf755b424b29098f4e7da url:https://raw.githubusercontent.com/postgres/postgres/753057e340da8f22e57c9a409ea7a235fd6a46bd/src/backend/commands/tablecmds.c] source_url:https://github.com/postgres/postgres/blob/753057e340da8f22e57c9a409ea7a235fd6a46bd/src/backend/commands/tablecmds.c variant:0a8d6d455ac7], map[label:ALTER TABLE … ADD FOREIGN KEY [NOT VALID] (referencing table) note:Both referencing and referenced tables take SHARE ROW EXCLUSIVE. NOT VALID skips the initial data check, not this lock. slug:alter-table source:map[kind:command-documentation path:doc/src/sgml/ref/alter_table.sgml revision:753057e340da8f22e57c9a409ea7a235fd6a46bd sha256:10436673fa2f093bdf51986a06d22dd748a9bb003bcd5517db2a65fba569a3c9 url:https://raw.githubusercontent.com/postgres/postgres/753057e340da8f22e57c9a409ea7a235fd6a46bd/doc/src/sgml/ref/alter_table.sgml] source_url:https://www.postgresql.org/docs/18/sql-altertable.html variant:534bfcc33099], map[label:ALTER TABLE … ADD FOREIGN KEY [NOT VALID] (referenced table) note:The referenced table also takes SHARE ROW EXCLUSIVE, not merely ACCESS SHARE. slug:alter-table source:map[kind:command-documentation path:doc/src/sgml/ref/alter_table.sgml revision:753057e340da8f22e57c9a409ea7a235fd6a46bd sha256:10436673fa2f093bdf51986a06d22dd748a9bb003bcd5517db2a65fba569a3c9 url:https://raw.githubusercontent.com/postgres/postgres/753057e340da8f22e57c9a409ea7a235fd6a46bd/doc/src/sgml/ref/alter_table.sgml] source_url:https://www.postgresql.org/docs/18/sql-altertable.html variant:d12c1f8a164b]

provenance

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summary

Conflicts with the ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE, EXCLUSIVE, and ACCESS EXCLUSIVE lock modes. This mode protects a table against concurrent data changes, and is self-exclusive so that only one session can hold it at a time.

Source references

Full definition and evidence JSON

Definition sources

center · PostgreSQL 18 · wiki-repair-20261023:6bd68ec5c9f29a27ddf3ae0eb18218c4dda4da20416d69a8a2b88f5fcaef6ec4

Text language: en · wiki-repair-20261023:6bd68ec5c9f29a27ddf3ae0eb18218c4dda4da20416d69a8a2b88f5fcaef6ec4