(1ROW) 由此可见,pg_table_size是pg_relation_size所有返回值的总和。 而pg_total_relation_size是pg_table_size和pg_indexes_size的总和。 如果您想知道表正在使用多少空间,请使用pg_table_size和pg_total_relation_size考虑它们-一个数字是仅表的,一个数字是表+索引的。 检查存储文件的布局,以获取有关fsm,v...
pool的缓存管理机制不同，Postgresql采用数据库采用实例buffer和操作系统buffer双缓存(effective_cache_size)...
select indexrelname, pg_size_pretty(pg_relation_size(relid)) as size from pg_stat_user_indexes where schemaname='public'; 名词解释 FSM,指的是Free Space Map,空闲空间映射表。一个relation有多个8KB大小的block,这些block存储在磁盘上。一个relation最大只能有4G个block,每个block大小为8KB,也就是说一...
select relname tablename,(pg_relation_size(indexrelid))/1024/1024/1024 indexsize, t.unnest_idx_count idx_cnt from pg_class c ,t where c.oid=t.indrelid order by 2 desc; 图12:按大小排序的复合索引 这里,我们很清楚发现,部分索引的大小都在500G以上,有10多个索引的size超过1TB,看到这些信息时,...
ORDER BY pg_relation_size(i.indexrelid) / nullif(idx_scan, 0) DESC NULLS FIRST, pg_relation_size(i.indexrelid) DESC; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 在PostgreSQL 中,WAL(Write-Ahead Logging)是一种机制,用于确保数据的持久性和一致性。WALWrite 和 WALSync 都是与 WAL 相关...
SELECT reltuples * (pg_relation_size('flights_copy') / 8192) / relpages FROM pg_class WHERE relname = 'flights_copy'; ?column? −−−−−−−−−− 429734 (1 row) 这种调整并不总是有效,例如可以删除几行,但估算值不会变化。但当发生较大变化时,这种方法可以让统计数据保持...
,pg_size_pretty(pg_relation_size('"'||schemaname|| '"."'||relname||'"')) as "table_size(表大小)" ,n_dead_tup as "n_dead_tup(无效记录数)" ,n_live_tup as "n_live_tup(有效记录数)" ,to_char(round(n_dead_tup*1.0/(n_live_tup+n_dead_tup)*100,2),'fm990.00') as "dea...
select pg_size_pretty(pg_relation_size('film_fulltext_idx')); -- 88 kB 1. 2. 顺便说下,也可以查看整个数据库: SELECT pg_size_pretty(pg_database_size('dvdrental')); -- 15 MB 1. 2. 查看前10个最大关系信息: SELECT relname AS "relation", pg_size_pretty(pg_relation_size(C.oid))...
pg_relation_size --- 0 (1 row) 以KB,MB,GB的方式来查看表大小 playboy=> select pg_size_pretty(pg_relation_size('test')); pg_size_pretty --- 0 bytes (1 row) 统计数据库中各表占用磁盘大小: SELECT table_schema || '.' || table_name...
SELECTpg_relation_size('table_name');-- 更好的显示格式SELECTpg_size_pretty(pg_relation_size('table_name')); 查看全部表的大小 以下查询返回了数据库中全部表的大小,从大到小进行排序: SELECTrelnameASrelation,pg_size_pretty(pg_total_relation_size(C.oid))AStotal_sizeFROMpg_classCLEFTJOINpg_name...