On Wed, May 25, 2022 at 12:25:28AM +0800, 徐志宇徐 wrote: > Hi All > > I am a Database DBA. I focus on PostgreSQL and DB2. > Recently. I experience some memory issue. The postgres unable allocate > memory. I don't know how to monitor Postgres memory usage. Postgres is just an OS Process, so should be monitored like any other. What OS are you using ? Know that the OS may attribute "shared buffers" to different processes, or multiple processes. > This server have 16G memory. On that time. The free command display only 3 > G memory used. The share_buffers almost 6G. > > On that time. The server have 100 active applications. > New connection failed. I have to kill some application by os command "kill -9" It's almost always a bad idea to kill postgres with kill -9. > The checkpoint command execute very slow. almost need 5-10 seconds. Do you mean an interactive checkpoint command ? Or logs from log_checkpoint ? > Is there any useful command to summary PostgreSQL memory usage ? You can check memory use of an individual query with "explain (analyze,buffers) .." https://wiki.postgresql.org/wiki/Slow_Query_Questions What settings have you used in postgres ? https://wiki.postgresql.org/wiki/Server_Configuration What postgres version ? How was it installed ? From souce? From a package ? -- Justin
