Re: PG 11.8 > PG 12.3 : Unable to allocate section memory

Please specify some other stuff:

1. PG onprem or cloud? If cloud, which one and what instance type.
2. Is it a dedicated PG host?  How many hyper threads and memory do you have?
3. Does PGBouncer run on another host or on the same host as PG?

JOIGNY Michael @Neteven wrote on 8/12/2020 10:09 AM:

Hi Community, We have migrated from postgresql 11.8 to 12.3, unfortunately we have sometimes the following errors in the logs, causing postgres process to be killed.

2020-08-12 14:20:29.043 CEST [134644]: [71-1] user=xx,db=xx,app=[unknown],client=localhost FATAL:  out of memory
2020-08-12 14:20:29.049 CEST [30022]: [6126-1] user=xx,db=xx,app=[unknown],client=localhost FATAL:  fatal llvm error: Unable to allocate section memory!
2020-08-12 14:20:29.197 CEST [78792]: [1-1] user=,db=,app=,client= FATAL:  terminating connection due to administrator command
2020-08-12 14:20:29.197 CEST [78791]: [1-1] user=,db=,app=,client= FATAL:  terminating connection due to administrator command
2020-08-12 14:20:29.197 CEST [78793]: [1-1] user=,db=,app=,client= FATAL:  terminating connection due to administrator command
2020-08-12 14:20:29.197 CEST [78790]: [1-1] user=,db=,app=,client= FATAL:  terminating connection due to administrator command
2020-08-12 14:21:02.621 CEST [86289]: [2-1] user=postgres,db=template1,app=[unknown],client=[local] FATAL:  out of memory
2020-08-12 14:21:04.632 CEST [29597]: [26704-1] user=xx,db=xx,app=[unknown],client=localhost FATAL:  fatal llvm error: Unable to allocate section memory!

Here are our settings :

PG :

max_connections = 3600    

shared_buffers = 32GB           
temp_buffers = 16MB                
work_mem = 96MB                    
maintenance_work_mem = 8GB           
max_stack_depth = 6MB                  
dynamic_shared_memory_type = posix 

We use postgresql with pgbouncer as a pooler. 

PGbouncer :

pooler mode : session
max_client_conn = 6000
default_pool_size = 3000We have ~ 2000 connections at the same time with ~ 20/30 are active.

Note that we had the same configuration under PG11 without any problem.

Do you have an idea ?

Regards.