Out of memory on vacuum analyze
I have a large table (~55 million rows) and I'm trying to create an index
and vacuum analyze it. The index has now been created, but the vacuum
analyze is failing with the following error:
ERROR: out of memory
DETAIL: Failed on request of size 943718400.
I've played with several settings, but I'm not sure what I need to set to
get this to operate. I'm running on a dual Quad core system with 4GB of
memory and Postgresql 8.2.3 on W2K3 Server R2 32bit.
Maintenance_work_mem is 900MB
Max_stack_depth is 3MB
Shared_buffers is 900MB
Temp_buffers is 32MB
Work_mem is 16MB
Max_fsm_pages is 204800
Max_connections is 50
Any help would be greatly appreciated.
Thanks,
John Cole
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On Mon, 2007-02-19 at 12:47 -0600, John Cole wrote:
I have a large table (~55 million rows) and I'm trying to create an index
and vacuum analyze it. The index has now been created, but the vacuum
analyze is failing with the following error:ERROR: out of memory
DETAIL: Failed on request of size 943718400.I've played with several settings, but I'm not sure what I need to set to
get this to operate. I'm running on a dual Quad core system with 4GB of
memory and Postgresql 8.2.3 on W2K3 Server R2 32bit.Maintenance_work_mem is 900MB
Max_stack_depth is 3MB
Shared_buffers is 900MB
Temp_buffers is 32MB
Work_mem is 16MB
Max_fsm_pages is 204800
Max_connections is 50
You told PostgreSQL that you have 900MB available for
maintenance_work_mem, but your OS is denying the request. Try *lowering*
that setting to something that your OS will allow. That seems like an
awfully high setting to me.
Regards,
Jeff Davis
On Feb 19, 2007, at 1:19 PM, Jeff Davis wrote:
You told PostgreSQL that you have 900MB available for
maintenance_work_mem, but your OS is denying the request. Try
*lowering*
that setting to something that your OS will allow. That seems like an
awfully high setting to me.
900MB isn't that unreasonable if you're building indexes on a restore
or something similar. I have run into issues when trying to set it
much over 1G, though... on various OSes and platforms.
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Jim Nasby wrote:
On Feb 19, 2007, at 1:19 PM, Jeff Davis wrote:
You told PostgreSQL that you have 900MB available for
maintenance_work_mem, but your OS is denying the request. Try *lowering*
that setting to something that your OS will allow. That seems like an
awfully high setting to me.900MB isn't that unreasonable if you're building indexes on a restore or
something similar. I have run into issues when trying to set it much
over 1G, though... on various OSes and platforms.
versions before 8.2 have some issues(mostly reporting bogus errors) with
very large settings for maintenance_work_mem. 8.2 and up are behaving
more sanely but I don't think they can actually make anything better
with values in the GB range.
Have you actually measured a performance improvment going beyond
250-350MB(that seemed about to be the sweet spot last I tested) or so
for index creation and friends ?
Stefan
On Feb 21, 2007, at 12:58 AM, Stefan Kaltenbrunner wrote:
Have you actually measured a performance improvment going beyond
250-350MB(that seemed about to be the sweet spot last I tested) or so
for index creation and friends ?
To be honest, no; I just set it high to play on the safe side. But I
have seen reports of large in-memory sorts actually being slower than
tape sorts in some cases, so I probably am leaving some performance
on the table.
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)