aurora_stat_logical_wal_cache - Amazon Aurora
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

aurora_stat_logical_wal_cache

Shows logical write-ahead log (WAL) cache usage per slot.

Syntax

SELECT * FROM aurora_stat_logical_wal_cache()

Arguments

None

Return type

SETOF record with the following columns:

  • name – The name of the replication slot.

  • active_pid – ID of the walsender process.

  • cache_hit – The total number of wal cache hits since last reset.

  • cache_miss – The total number of wal cache misses since last reset.

  • blks_read – The total number of wal cache read requests.

  • hit_rate – The WAL cache hit rate (cache_hit / blks_read).

  • last_reset_timestamp – Last time that the counter was reset.

Usage notes

This function is available for the following versions.

  • Aurora PostgreSQL 14.7

  • Aurora PostgreSQL version 13.8 and higher

  • Aurora PostgreSQL version 12.12 and higher

  • Aurora PostgreSQLversion 11.17 and higher

Examples

The following example shows two replication slots with only one active. aurora_stat_logical_wal_cache function.

=> SELECT * FROM aurora_stat_logical_wal_cache(); name | active_pid | cache_hit | cache_miss | blks_read | hit_rate | last_reset_timestamp ------------+------------+-----------+------------+-----------+----------+------------------------------- test_slot1 | 79183 | 24 | 0 | 24 | 100.00% | 2022-08-05 17:39:56.830635+00 test_slot2 | | 1 | 0 | 1 | 100.00% | 2022-08-05 17:34:04.036795+00 (2 rows)