On 06/29/2015 11:49 AM, Edson Richter wrote:
> Dear community,
>
> I'm using PostgreSQL 9.3.6 on Linux x64.
>
> Would sound a stupid questions, and sorry if it was already asked
> before: if I set the "archive_timeout", and then I have them sent every
> minute (for example), are the files still 16MB in size, or are they
> truncated and sent in smaller sizes as well?
> I've not found this information in docs.
See here:
http://www.postgresql.org/docs/9.4/interactive/runtime-config-wal.html#RUNTIME-CONFIG-WAL-ARCHIVING
"archive_timeout (integer)
The archive_command is only invoked for completed WAL segments.
Hence, if your server generates little WAL traffic (or has slack periods
where it does so), there could be a long delay between the completion of
a transaction and its safe recording in archive storage. To limit how
old unarchived data can be, you can set archive_timeout to force the
server to switch to a new WAL segment file periodically. When this
parameter is greater than zero, the server will switch to a new segment
file whenever this many seconds have elapsed since the last segment file
switch, and there has been any database activity, including a single
checkpoint. (Increasing checkpoint_timeout will reduce unnecessary
checkpoints on an idle system.) Note that archived
^^^^^^^^^^^^^^^^^^
files that are closed early due to a forced switch are still the same
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
length as completely full files. Therefore, it is unwise to use a very
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
short archive_timeout — it will bloat your archive storage.
archive_timeout settings of a minute or so are usually reasonable. You
should consider using streaming replication, instead of archiving, if
you want data to be copied off the master server more quickly than that.
This parameter can only be set in the postgresql.conf file or on the
server command line.
"
>
> Thanks,
>
--
Adrian Klaver
adrian.klaver@aklaver.com