<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt">Hi,<br><br>Indeed i use streaming replication, i will study the pgpool replication fro my nr1 problem. As for the second i will give it a try.<br>Thanks very much for the quick response.<br><div><span><br></span></div><div> </div><div>Regards,<br>Adrian Videanu<br></div> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Tatsuo Ishii <ishii@postgresql.org><br> <b><span style="font-weight: bold;">To:</span></b> videanuadrian@yahoo.com <br><b><span style="font-weight: bold;">Cc:</span></b> pgpool-general@pgpool.net <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, February
27, 2013 1:52 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [pgpool-general: 1436] postgresql node to other geographic region<br> </font> </div> <br>
> Hi all, i currently have a pgpool cluster (v 3.1.3) built from 3 nodes. <br>> First problem is that i have some apps that perform operations like this : <br>> <br>> 1. insert one row (executes on node1)<br>> 2. select some info from previous insert (executes on node 1 or 2 or 3) <- i guess that here is the problem because the commands are successive and i pgpool does not has enough time to replicate the data, and this query returns nothing. Also this behavior is random, sometimes works as expected sometimes not. <br><br>Assuming you are using streaming replication mode, the replication<br>delay you are observing is caused by PostgreSQL's streaming<br>replication nature, not by pgpool, because it is *asynchronous*<br>replication. If you don't like it, you'd better to use pgpool's<br>replication mode.<br><br>> 3. perform some insert based on previous select.<br>> <br>> I have "managed" this problem by reading
and writing only from master node, and the other two nodes are used hot standby. I`m aware of the fact that if master fails only slave 2 will become master and the 3rd will not switch to node 2 as master.<br><br>No. Which standby promotes is depending on the fail over script. And<br>it is users's responsibility to write appropreate fail over script.<br><br>> So the second problem would be: <br>> <br>> how will pgpool behaves if i move that 3rd node to other geographic location and in a different subnet ? I expect to have so downtimes to the order of seconds once in a while..<br><br>That should not be much longer than the case which all nodes are on<br>the same LAN. Rather I'm afraid the replication delay caused by the<br>network delay.<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><br> </div> </div> </div></body></html>