<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Times New Roman; font-size: 14pt; color: #000000'>What means "The size of the cache is vary from cache to cache, but typical size is 128" the size is in bytes?<br><br>Regards.<br><br><hr id="zwchr"><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;">> On Mon, Jun 4, 2012 at 3:40 PM, Tatsuo Ishii <ishii@postgresql.org> wrote:<br>>>> You're correct, I only needed to perform a reload. I kept this change<br>>>> enabled for all of 36 seconds, and in that time there were 1597 times<br>>>> that the following query was logged originating from the pgpool server<br>>>> IP address:<br>>>> SELECT count(*) FROM pg_catalog.pg_class AS c WHERE c.oid ...<br>>>><br>>>> 3204 times that the following query was logged originating from the<br>>>> pgpool server IP address:<br>>>> SELECT count(*) FROM pg_class AS c, pg_namespace AS n WHERE c.relname ...<br>>>><br>>>> Those numbers seem excessive to me, but perhaps this is<br>>>> expected/normal? It definitely seems like it would explain why perf<br>>>> always degrades whenever the master is very busy, if that volume of<br>>>> queries needs to be sustained.<br>>><br>>> That depends on your use case. If client's query involves many tables,<br>>> it requires many catalog lookups. Also the catalog cache of pgpool's<br>>> life time is same as pgpool child process lifetime. If you would show<br>>> me the complete log, I could make more precise analysis.<br>> <br>> Sure, attached as pg.log.gz.<br><br>Analyzing the log I noticed several things:<br><br>1) I see many sessions which frequently connects/disconnects(over 1800<br> in 36 seconds). That is, each session only lasts 20 ms in average.<br><br>2) A process issues exactly same query more than once. This suggests<br> that relcache (catalog cache) size might be too small for your<br> environment. The size of the cache is vary from cache to cache, but<br> typical size is 128. So if you access more than 128 tables via<br> pgpool, the cache replacement will happen. How many tables do you<br> have?<br><br>2) The are many queries to check whether the table is a temporary one<br> or not(1589 times). Even if we increase the relcache size, we<br> cannot avoid this since the cache's life time is session. So it<br> might be worth to invent new swich to skip the check.<br>--<br>Tatsuo Ishii<br>SRA OSS, Inc. Japan<br>English: http://www.sraoss.co.jp/index_en.php<br>Japanese: http://www.sraoss.co.jp<br>_______________________________________________<br>pgpool-general mailing list<br>pgpool-general@pgpool.net<br>http://www.pgpool.net/mailman/listinfo/pgpool-general<br><br>10mo. ANIVERSARIO DE LA CREACION DE LA UNIVERSIDAD DE LAS CIENCIAS INFORMATICAS...<br>CONECTADOS AL FUTURO, CONECTADOS A LA REVOLUCION<br><br>http://www.uci.cu<br>http://www.facebook.com/universidad.uci<br>http://www.flickr.com/photos/universidad_uci<br></blockquote><br></div>
<br><html>
<body>
<a href="http://www.uci.cu/">
<img src="http://universidad.uci.cu/email.gif"/>
</body>
</html>
<br></body></html>