[pgpool-general: 540] Re: load balancing seems to be bottlenecked by performance of master
dmk at mr-paradox.net
Tue May 29 10:37:24 JST 2012
On 05/28/2012 05:55 PM, Tatsuo Ishii wrote:
>> On Mon, May 28, 2012 at 5:23 PM, Tatsuo Ishii<ishii at postgresql.org> wrote:
>>>> On Mon, May 28, 2012 at 3:54 PM, Tatsuo Ishii<ishii at sraoss.co.jp> wrote:
>>>>>> What are the reasons for analysing system catalogs on primary server?
>>>>> For example, if a table is a temporary one or not.
>>>> Yes, but as I noted, I don't use temp tables at all. If this is the
>>>> primary justification, then its not doing me any good, and causing
>>>> unnecessary negative performance impact.
>>> But how does pgpool know that you are not going to use temporary
>>> tables beforehand?
>> Provide a new pgpool.conf option that tells it to ignore them (with
>> the assumption that they do not exist).
>>>> I understand if this isn't something you can fix right now, but I'm
>>>> not even getting the impression that you consider this to be a design
>>>> flaw. A high write volume on the master should never impact the
>>>> response time of any standby/slave with a read query. This literally
>>>> means that pgpool doesn't scale well in write heavy environments.
>>> That's why I asked you any idea to solve the problem.
>> I guess I don't understand why pgpool needs to look up the system
>> catalogs on the write server. Shouldn't they be identical on all
> You cannot assume that because streaming replication or slony are
> async replication.
> Also remember that temp tables can only be used on primary.
could you create a list of valid tables at startup and periodically poll
for new tables? if it's an unlogged table you'll know, and if it's a
temp table (or a very new table) you just wouldn't allow it to be load
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