GaussDB(DWS)系统表清理指南

系统表由于长时间运行会不断累积，尤其是大量的创建对象（表、视图等）和删除对象更会造成系统表膨胀，系统表膨胀后可能会导致查询性能降低，需要进行垃圾数据清理。清理命令如下：

omm用户连接cn执行如下sql进行清理

VACUUM FULL PG_ATTRIBUTE;

VACUUM FULL PG_CLASS;

VACUUM FULL PG_CONSTRAINT;

VACUUM FULL PG_DATABASE;

VACUUM FULL PG_PARTITION;

VACUUM FULL PG_PROC;

VACUUM FULL PG_STAT_USER_INDEXES;

VACUUM FULL PG_STAT_USER_TABLES;

VACUUM FULL PG_STATISTIC;

VACUUM FULL PG_STATS;

ANALYZE PG_ATTRIBUTE;

ANALYZE PG_CLASS;

ANALYZE PG_CONSTRAINT;

ANALYZE PG_DATABASE;

ANALYZE PG_PARTITION;

ANALYZE PG_PROC;

ANALYZE PG_STAT_USER_INDEXES;

ANALYZE PG_STAT_USER_TABLES;

ANALYZE PG_STATISTIC;

ANALYZE PG_STATS;

注意：

1、系统表清理会锁系统表，需在业务低峰期且没有DDL操作时执行；

2、这些系统表是database级别的，需要对每个database执行一遍，或针对明确有膨胀的database执行。