PostgreSQL 15 preview - postgres_fdw: Make postgres_fdw.application_name support more escape sequences.

作者

digoal

日期

2022-02-21

标签

PostgreSQL , postgres_fdw , application_name

postgres_fdw application_name 提供更多通配符的支持. session ID (%c) and cluster name (%C) 可以更方便的对外部表会话进行管理.

https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=94c49d53402240ad7ddbcae9049ff2840a54b9c6

postgres_fdw: Make postgres_fdw.application_name support more escape sequences.  
author  Fujii Masao <fujii@postgresql.org>    
Fri, 18 Feb 2022 02:38:12 +0000 (11:38 +0900)  
committer   Fujii Masao <fujii@postgresql.org>    
Fri, 18 Feb 2022 02:38:12 +0000 (11:38 +0900)  
commit  94c49d53402240ad7ddbcae9049ff2840a54b9c6  
tree    bff534c8386626a4278a2dd9ac743ae3a50dc351    tree  
parent  c476f380e296bab57fecada1ea96c86d575bf160    commit | diff  
postgres_fdw: Make postgres_fdw.application_name support more escape sequences.  
Commit 6e0cb3dec1 allowed postgres_fdw.application_name to include  
escape sequences %a (application name), %d (database name), %u (user name)  
and %p (pid). In addition to them, this commit makes it support  
the escape sequences for session ID (%c) and cluster name (%C).  
These are helpful to investigate where each remote transactions came from.  
Author: Fujii Masao  
Reviewed-by: Ryohei Takahashi, Kyotaro Horiguchi  
Discussion: https://postgr.es/m/1041dc9a-c976-049f-9f14-e7d94c29c4b2@oss.nttdata.com  

+        <row>  
+         <entry><literal>%c</literal></entry>  
+         <entry>  
+          Session ID on local server  
+          (see <xref linkend="guc-log-line-prefix"/> for details)  
+         </entry>  
+        </row>  
+        <row>  
+         <entry><literal>%C</literal></entry>  
+         <entry>  
+          Cluster name in local server  
+          (see <xref linkend="guc-cluster-name"/> for details)  
+         </entry>  
+        </row>  

+-- Test %c (session ID) and %C (cluster name) escape sequences.  
+SET postgres_fdw.application_name TO 'fdw_%C%c';  
+SELECT 1 FROM ft6 LIMIT 1;  
+ ?column?   
+----------  
+        1  
+(1 row)  
+  
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity  
+  WHERE application_name =  
+    substring('fdw_' || current_setting('cluster_name') ||  
+      to_hex(trunc(EXTRACT(EPOCH FROM (SELECT backend_start FROM  
+      pg_stat_get_activity(pg_backend_pid()))))::integer) || '.' ||  
+      to_hex(pg_backend_pid())  
+      for current_setting('max_identifier_length')::int);  
+ pg_terminate_backend   
+----------------------  
+ t  
+(1 row)  
+  

https://www.postgresql.org/docs/devel/postgres-fdw.html#id-1.11.7.45.11

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