postgresql连接报错：could not fork new process for conn

虽然数据库设置了最大连接数是2000，但是当连接数达到1000时。再也不能接受连接，而是报错：could not fork new process for connection: Resource temporarily unavailable。

这个错误的原因是操作系统单个用户的进程数量限制。报错，但不用记录到PG的日志中。

例如

@H_301_8@[postgres@localhost ~]$ ps -ef | grep postgres

@H_301_8@postgres 2704 1 0 16:10 pts/1 00:00:00 /usr/local/pgsql941/bin/postgres

@H_301_8@.....

主进程号是2704

@H_301_8@# cd /proc/2704

@H_301_8@# cat limits

@H_301_8@Limit Soft Limit Hard Limit Units

@H_301_8@Max cpu time unlimited unlimited seconds

@H_301_8@Max file size unlimited unlimited bytes

@H_301_8@Max data size unlimited unlimited bytes

@H_301_8@Max stack size 10485760 unlimited bytes

@H_301_8@Max core file size unlimited unlimited bytes

@H_301_8@Max resident set unlimited unlimited bytes

@H_301_8@Max processes 1024 131072 processes

@H_301_8@Max open files 131072 131072 files

@H_301_8@Max locked memory 51200000000 51200000000 bytes

@H_301_8@Max address space unlimited unlimited bytes

@H_301_8@Max file locks unlimited unlimited locks

@H_301_8@Max pending signals 256607 256607 signals

@H_301_8@Max msgqueue size 819200 819200 bytes

@H_301_8@Max nice priority 0 0

@H_301_8@Max realtime priority 0 0

@H_301_8@Max realtime timeout unlimited unlimited us

可以看到Max processes限制是1024

@H_301_8@# echo -n "Max processes=131072:131072" > limits