huge memory of Postgresql backend process - Mailing list pgsql-bugs

From James Pang (chaolpan)
Subject huge memory of Postgresql backend process
Date
Msg-id PH0PR11MB51911F681F37F55A92DA4C01D6409@PH0PR11MB5191.namprd11.prod.outlook.com
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Responses Re: huge memory of Postgresql backend process
List pgsql-bugs

Hi,

  We just switch from Oracle to PGV13, all of these tables got partition (256 HASH partition) ,  when UPDATE/DELETE … WHERE . The memory increase verify quickly until >130M. not too much data in these tables.  When we switch to PGV14.5 , test again, still see similar memory consumption issue. For example , one  Postgresql JDBC client ,

 

  PID USER              PR  NI    VIRT       RES    SHR       S  %CPU  %MEM     TIME+ nMaj nMin WCHAN       COMMAND

551701 postgres  20   0   45.6g   131468  11664 S   0.0   0.1   0:03.11    0  35k do_epoll_w+ postgres:

 

When we rebuild the table to no-partitioned tables , same table columns and same data size, the “RES” memory only  25MB.   For both partitioned and non-partitioned table, the UPDATE/DELETE run fast. The only difference is big difference on memory consumption.  And even the session is IDLE there long time, the backend process did NOT release memory to OS.   Is it expected to see that ?  

 

  Server memory 128G, shared_buffer 45G,    effective_cache_size=80G.   PG server both V13.4 and V14.5 has same issue.  Postgresql JDBC client driver  42.3.4

 

Thanks,

 

James

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