Re: [9.0] hot standby plus streaming replication

Fujii Masao ha scritto:
> On Fri, Oct 1, 2010 at 4:02 PM, Michele Petrazzo - Unipex
> <michele.petrazzo@unipex.it>  wrote:
>> - why in my tests, _whitout_ common direcotory, master and slave
>> keep in sync also if I shutdown slave, add (in my last tests)
>> something about 100k record (although little ones) on the master
>> and then after woke up the slave in about 2/3 seconds I have all
>> the dbs in sync?
>
> Because the master had the WAL files containing that 100k record in
> its pg_xlog directory. If those WAL files were unfortunately removed
>  from the master before you started the standby, the standby would
> not have been in sync with the master.
>

This was the explain that I was looking for!
Do you know if there is a talk or a "best practice" about keep in sync a
master/slave couple without a shared directory? Something that talk
about the number of a typical data that can be keep in sync.
Can be very useful and more simple to maintain an installation without a
shared than a one with it and I think that more users will be happy with!

> You can specify how many WAL files you'd keep in the master by using
> wal_keep_segments parameter.
> http://developer.postgresql.org/pgdocs/postgres/runtime-config-wal.html#RUNTIME-CONFIG-REPLICATION
>

Seen!
Thanks a lot,
Michele