# Lock Management

> Complete dossiers for 5 core PostgreSQL settings in Lock Management.
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Dossier URLs remain flat; this category exists only to organize browsing and the sidebar.

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Section pages:

- [deadlock_timeout](/parameters/deadlock-timeout/): deadlock_timeout — Sets the time to wait on a lock before checking for deadlock. Observed in PG9.0–19 Beta 3; its last measured boot default is 1 s in PG19 Beta 3, with superuser context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
- [max_locks_per_transaction](/parameters/max-locks-per-transaction/): max_locks_per_transaction — Sets the maximum number of locks per transaction. Observed in PG9.0–19 Beta 3; its last measured boot default is 128 in PG19 Beta 3, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
- [max_pred_locks_per_page](/parameters/max-pred-locks-per-page/): max_pred_locks_per_page — Sets the maximum number of predicate-locked tuples per page. Observed in PG10–19 Beta 3; its last measured boot default is 2 in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
- [max_pred_locks_per_relation](/parameters/max-pred-locks-per-relation/): max_pred_locks_per_relation — Sets the maximum number of predicate-locked pages and tuples per relation. Observed in PG10–19 Beta 3; its last measured boot default is -2 in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
- [max_pred_locks_per_transaction](/parameters/max-pred-locks-per-transaction/): max_pred_locks_per_transaction — Sets the maximum number of predicate locks per transaction. Observed in PG9.1–19 Beta 3; its last measured boot default is 64 in PG19 Beta 3, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.