Обсуждение: pg_xlog and the WAL files

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pg_xlog and the WAL files

От
"Achakzai, Omar"
Дата:
Hi,
 
I have two questions about PostgreSQL:
 
1. What happens when the file system on which the pg_xlog directly resides, completely fills up? Does PostgreSQL wait until free space is available again?

2. Our PostgreSQL database (version 8.1.4.) generates almost 20 GB of WAL files per hour! What are the best practices related to administering large amounts of WAL files? Would it be wise to compress the WAL files?
 
Thanks in advance,
 
Kind regards,
 
Omar


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Re: pg_xlog and the WAL files

От
Tom Lane
Дата:
"Achakzai, Omar" <omar.achakzai@logicacmg.com> writes:
> 1. What happens when the file system on which the pg_xlog directly resides,=
>  completely fills up? Does PostgreSQL wait until free space is available ag=
> ain?=20

I believe it'll PANIC and shut down.  You won't lose any committed
transactions ... but transactions in progress are out of luck.

> 2. Our PostgreSQL database (version 8.1.4.) generates almost 20 GB of WAL f=
> iles per hour! What are the best practices related to administering large a=
> mounts of WAL files? Would it be wise to compress the WAL files?=20

What are your checkpoint settings?  Reducing checkpoint frequency is one
way to cut the WAL volume.

            regards, tom lane