ALTERTABLEtb1SET(vacuum_truncate=off); 将主库上的old_snapshot_threshold设置为-1以外的值。这会禁用VACUUM截断,这是未被记录的副作用。
old_snapshot_threshold:设置可以使用查询快照的最小时间,以规避使用快照时出现“snapshot too old” 错误的风险,超过此阈值时间的数据将可以被清除,这可以有助于阻止长时间使用的快照造成的快照膨胀,默认值为 -1(禁用此功能),实际上将快照的时限设置为无穷大。 log_autovacuum_min_duration:超过这个时间阀值的自动清...
max_parallel_workers_per_gather = 16 old_snapshot_threshold = 8h backend_flush_after = 256 synchronous_commit = off full_page_writes = off wal_buffers = 128MB wal_writer_delay = 10ms wal_writer_flush_after = 4MB checkpoint_timeout = 55min max_wal_size = 256GB checkpoint_flush_after...
#max_parallel_workers = 8 # 可以在并行操作中使用的max_worker_processes的最大数量 #old_snapshot_threshold = -1 # 1min-60d; -1:禁用 0:立刻(更改需要重新启动PG数据库生效) #backend_flush_after = 0 # 以页为单位测量,0-禁用 1. 2. 3. 4. 5. 6. 7. 8. 1.4 预写日志(WRITE-AHEAD LOG...
vacuum_defer_cleanup_age:主从架构中,指定主库 vacuum 清除死亡行版本之前,应该推迟多久(以事务数量计),默认值 0,这允许备机上的查询,有更多时间来完成而不会由于先前的行清除产生冲突。比 old_snapshot_threshold 参数优先级低。 vacuum_freeze_min_age:指定 vacuum 操作的冻结年龄(当前事务id - 上一次冻结事务...
old_snapshot_threshold = 8h backend_flush_after = 256 synchronous_commit = off full_page_writes = off wal_buffers = 128MB wal_writer_delay = 10ms wal_writer_flush_after = 4MB checkpoint_timeout = 55min max_wal_size = 256GB
old_snapshot_threshold = 6h wal_level = hot_standby synchronous_commit = off full_page_writes = on wal_compression = on wal_buffers = 16MB wal_writer_delay = 10ms wal_writer_flush_after = 1MB checkpoint_timeout = 30min checkpoint_completion_target = 0.2 ...
Database cluster(数据库集簇): 由postgresql server管理的数据库的集合,下面由多个database组成。一个数据库集簇可以包含多个Database、多个User,每个Database以及Database中的所有对象都有它们的所有者:User。 Database数据库:Postgres 默认数据库、Template0 最精简模板、Template1 默认模板;数据库本身也是数据库对象...
OldSnapshotControlData | 147126016 | 68 | 128 PMSignalState | 146710784 | 1020 | 1024 PREDICATELOCK hash | 144281216 | 2904 | 2944 PredXactList | 145541632 | 88 | 128 Notify | 147131008 | 66816 | 66816 Fast Path Strong Relation Lock Data | 143831680 | 4100 | 4224 pg_stat_statements ...
https://www.postgresql.org/docs/current/oldsnapshot.html PostgreSQL 1.0 CONTRIB C f t t t f f {17,16,15,14} 1.0 CONTRIB postgresql$v-contrib {17,16,15,14} 1.0 CONTRIB postgresql-$v {17,16,15,14} utilities in support of old_snapshot_threshold 支持old_snapshot_threshold 的实用程序...