[pgpool-hackers: 363] Re: Auto-learning database-modifying functions

[Tatsuo Ishii]

> On Wed, Sep 11, 2013 at 08:31:30PM +0500, Ahsan Hadi wrote:
>>     > I know you can specify a pattern to identify database-modifying
>>     > functions, but I am wondering if you could send queries containing
>>     > questionable functions to the read-only server, and if you get a
>>     > read-only error, then send them to the write server.  A more interesting

I think the "resend the failed query to master server if read-only
fails because of read-only error" part is pretty hard to implement if
user started an explicit transaction. To rery the query, you need to
remenber which as been succeeded and which result packets are already
sent to the user. I think the work to implement it is not worth the
gain.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp