Thread: Increase checkpoint segments ?

Increase checkpoint segments ?

From
Abu Mushayeed
Date:
Hello,

I have many updates happening in the DB. All of them works with millions of rows. When this happens I get the following message:

checkpoints are occurring too frequently (294 seconds apart)
Consider increasing the configuration parameter "checkpoint_segments".

Some values from my postgresql.conf files are as follows. My question is do I really increase the checkpoint segments or should I increase the WAL buffers or do an create table as and then insert instead of update statement?

shared_buffers = 20000 #60000                   # min 16 or max_connections*2, 8KB each -- Bizgres work_mem = 65536 #131072 #65536                 # min 64, size in KB -- Bizgres Database change from 1024 to 65536
maintenance_work_mem = 524288 #131072           # min 1024, size in KB
max_fsm_pages = 8000000                 # min max_fsm_relations*16, 6 bytes each
max_fsm_relations = 32768               # min 100, ~70 bytes each

fsync = on                              # turns forced synchronization on or off
wal_buffers = 128                       # min 4, 8KB each
checkpoint_segments = 256               # in logfile segments, min 1, 16MB each
checkpoint_timeout = 3600  #300         # range 30-3600, in seconds
checkpoint_warning = 300                # in seconds, 0 is off
default_statistics_target = 250         # range 1-1000

Thanks
Abu


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Re: Increase checkpoint segments ?

From
"Tomeh, Husam"
Date:
Typically in this scenario, more and larger WAL segments can help speed up your updates. However, the default size of a WAL segment is 16MB which can be set at postgresql compile time, and can not be changed thereafter. So, you'd need to increase the checkpoint_segments parameters to speed up your updates.  Increasing the WAL buffers which are memory pages allocated in the shared memory for WAL data won't help.
 
Sincerely,
 
--
  Husam

From: pgsql-admin-owner@postgresql.org [mailto:pgsql-admin-owner@postgresql.org] On Behalf Of Abu Mushayeed
Sent: Tuesday, December 12, 2006 9:17 AM
To: pgsql-admin@postgresql.org
Subject: [ADMIN] Increase checkpoint segments ?

Hello,

I have many updates happening in the DB. All of them works with millions of rows. When this happens I get the following message:

checkpoints are occurring too frequently (294 seconds apart)
Consider increasing the configuration parameter "checkpoint_segments".

Some values from my postgresql.conf files are as follows. My question is do I really increase the checkpoint segments or should I increase the WAL buffers or do an create table as and then insert instead of update statement?

shared_buffers = 20000 #60000                   # min 16 or max_connections*2, 8KB each -- Bizgres work_mem = 65536 #131072 #65536                 # min 64, size in KB -- Bizgres Database change from 1024 to 65536
maintenance_work_mem = 524288 #131072           # min 1024, size in KB
max_fsm_pages = 8000000                 # min max_fsm_relations*16, 6 bytes each
max_fsm_relations = 32768               # min 100, ~70 bytes each

fsync = on                              # turns forced synchronization on or off
wal_buffers = 128                       # min 4, 8KB each
checkpoint_segments = 256               # in logfile segments, min 1, 16MB each
checkpoint_timeout = 3600  #300         # range 30-3600, in seconds
checkpoint_warning = 300                # in seconds, 0 is off
default_statistics_target = 250         # range 1-1000

Thanks
Abu


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