Re: Streaming Replication: sql error on standby

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: "Sander, Ingo (NSN - DE/Munich)" <ingo(dot)sander(at)nsn(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Streaming Replication: sql error on standby
Date: 2010-06-25 15:49:57
Message-ID: AANLkTikgG2U0e_MMOMia16HI2PSStgXEzCBCBK6Qe0Om@mail.gmail.com
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On Wed, Jun 23, 2010 at 4:48 AM, Sander, Ingo (NSN - DE/Munich)
<ingo(dot)sander(at)nsn(dot)com> wrote:
> Sql query "select pg_last_xlog_receive_location(); " does not work during
> startup of standby database.
> TestScenario;
> We have a active-standby system with PostgreSQL Streaming Replication beta2.
> If the active database is up the database is in use (read/write queries will
> be performed). Then the standby PostgreSQL SR will be started (the complete
> database from the active side is copied to the standby side; nec. Files for
> starting streaming replication are created). Directly after the possibility
> to connect to the standby system, the above given sql query will be
> executed. To this timepoint the sql query delivers an error.

What is the error message?

> To a later
> timepoint (all wal segments are completly incooperated) the query delivers a
> valid result.
>
> Question:
> What is the reason for the error?
> Exists a command to find out if the standby database is really active to
> accept/can work with sql commands?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company

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