The following bug has been logged on the website:
Bug reference: 8034
Logged by: Devin Ben-Hur
Email address: dbenhur@whitepages.com
PostgreSQL version: 9.2.3
Operating system: Ubuntu Precise
Description: =
When a very large shared buffer pool (~480GB) is used with postgresql,
pg_buffercache contrib module gets an allocation error trying to Allocate
NBuffers worth of BufferCachePagesRec records:
https://github.com/postgres/postgres/blob/REL9_2_3/contrib/pg_buffercache/p=
g_buffercache_pages.c#L101-L102
The requested allocation exceeds the 1GB limitation imposed by
AllocSizeIsValid macro:
https://github.com/postgres/postgres/blob/REL9_2_3/src/include/utils/memuti=
ls.h#L40-L43
Reproduce:
1) acquire server with half terabyte of memory
2) tweak OS settings to allow large shared memory
3) set postgresql.conf: shared_buffers =3D 400GB
4) CREATE EXTENSION pg_buffercache;
5) SELECT * FROM pg_buffercache LIMIT 1;