PostgreSQL 15 preview - Increase size of shared memory for pg_commit_ts

作者

digoal

日期

2021-12-02

标签

PostgreSQL , pg_commit_ts , buffer

https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=4c83e59e01a89b0b19245b8e0317d87ae60226eb

Increase size of shared memory for pg_commit_ts  
author  Alvaro Herrera <alvherre@alvh.no-ip.org>      
Tue, 30 Nov 2021 17:29:31 +0000 (14:29 -0300)  
committer   Alvaro Herrera <alvherre@alvh.no-ip.org>      
Tue, 30 Nov 2021 17:29:31 +0000 (14:29 -0300)  
commit  4c83e59e01a89b0b19245b8e0317d87ae60226eb  
tree    c805dea8cd1415b358cb15a84410c89a6153e8fa    tree  
parent  e7122548a3f754060db1767582148b3559fe8d43    commit | diff  
Increase size of shared memory for pg_commit_ts  
Like 5364b357fb11 did for pg_commit, change the formula used to  
determine number of pg_commit_ts buffers, which helps performance with  
larger servers.  
Discussion: https://postgr.es/m/20210115220744.GA24457@alvherre.pgsql  
Reviewed-by: Noah Misch <noah@leadboat.com>  
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>  

- * We use a very similar logic as for the number of CLOG buffers; see comments  
- * in CLOGShmemBuffers.  
+ * We use a very similar logic as for the number of CLOG buffers (except we  
+ * scale up twice as fast with shared buffers, and the maximum is twice as  
+ * high); see comments in CLOGShmemBuffers.  
  */  
 Size  
 CommitTsShmemBuffers(void)  
 {  
-   return Min(16, Max(4, NBuffers / 1024));  
+   return Min(256, Max(4, NBuffers / 256));  
 }  

期望 PostgreSQL 增加什么功能?

类似Oracle RAC架构的PostgreSQL已开源: 阿里云PolarDB for PostgreSQL云原生分布式开源数据库!

PostgreSQL 解决方案集合

德哥 / digoal's github - 公益是一辈子的事.