Thread: Out of memory during index creation
Hello,
PG version 8.4.7 on AIX 6.1.
While creating a large multi-column index on a table of about 2.5 million rows, I got the following error:
ERROR: out of memory
DETAIL: Failed on request of size 50331648.
I doubled the value of the “shared_buffers” parameter (from 512Mb to 1024Mb), recycled the PG instance and then was able to run the “create index” statement successfully.
Question: Does PG use a main memory sort algorithm for the creation of indexes? Can it not make do with whatever memory is available and supplement it with disk space (external sort)? I have a temporaray tablespace defined (with the “temp_tablespaces”) parameter. The disk area for this tablespace had about 2GB of free space available. But the sort does not seem to have used it.
Thanks.
Alanoly Andrews.
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Alanoly Andrews <alanolya@invera.com> writes: > Hello, > > PG version 8.4.7 on AIX 6.1. > > While creating a large multi-column index on a table of about 2.5 million rows, I got the following error: > > ERROR: out of memory > > DETAIL: Failed on request of size 50331648. > > I doubled the value of the shared_buffers parameter (from 512Mb to 1024Mb), recycled the PG instance and then was ableto > run the create index statement successfully. > > Question: Does PG use a main memory sort algorithm for the creation of > indexes? Can it not make do with whatever memory is available and > supplement it with disk space (external sort)? I have a temporaray It can and does but for sorting too large to be done in maintenance_work_mem. If your box doesn't have enough virtual mem to support shared_buffers, work_mem on behalf of all live backends, whatever the OS needs... you'll get an error like that while Pg is trying to alloc for the maintenance_work_mem chunk. Inspect your logs for more cases of that error since autovac can run into the same problem. HTH > tablespace defined (with the temp_tablespaces) parameter. The disk > area for this tablespace had about 2GB of free space available. But > the sort does not seem to have used it. > > Thanks. > > Alanoly Andrews. > > ------------------------------------------------------------------------------------------------------------------------------ > This e-mail may be privileged and/or confidential, and the sender does not waive any related rights and obligations. Any > distribution, use or copying of this e-mail or the information it contains by other than an intended recipient is > unauthorized. If you received this e-mail in error, please advise me (by return e-mail or otherwise) immediately. > > Ce courriel est confidentiel et prot?g?. L'exp?diteur ne renonce pas aux droits et obligations qui s'y rapportent. Toute > diffusion, utilisation ou copie de ce message ou des renseignements qu'il contient par une personne autre que le (les) > destinataire(s) d?sign?(s) est interdite. Si vous recevez ce courriel par erreur, veuillez m'en aviser imm?diatement, par > retour de courriel ou par un autre moyen. > > Mail sent via the Abaca EPG > ------------------------------------------------------------------------------------------------------------------------------ > -- Jerry Sievers e: gsievers19@comcast.net p: 305.321.1144