[pgpool-general: 5389] Re: pgpool-ii across different countries different data centers)

[Tatsuo Ishii]

> Thanks so much Tatsuo..
> 
> For USA Pgpool-II:
>> backend_hostname0 = 'usasever.com'
>> backend_weight0 = 1
>> backend_hostname1 = 'asiasever.com'
>> backend_weight1 = 0
>>
>> For Asia Pgpool-II:
>> backend_hostname0 = 'usasever.com'
>> backend_weight0 = 0
>> backend_hostname1 = 'asiasever.com'
>> backend_weight1 = 1
>>
>> Notice the difference of weight0/1 parameter between USA and Aisa
>> Pgpool-II.
>>
> 
> 
> I have two webservers, one in the USA and one in Asia.
> 
> I won't be able to use virtual ip's (delegate_IP)
> 
> In this situation does my Asian webserver connect to the Asian/slave
> pgpool-II or the USA/master one?

I presume your Asian webserver connects to the Asian Pgpool-II in my
explanation.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

> Thanks in advance.
> 
> Cheers
> 
> Jon
> 
> 
>>
>> This way, all read/write access will be sent to usasever.com via USA
>> Pgpool-II. While all read access will be sent to asiaserver.com and
>> all write access will be sent to usaserver.com via Asia Pgpool-II.
>>
>> Problem is, Pgpool-II generates internal queries to the master server
>> (in your case usaserver.com). This happens when Pgpool-II needs to
>> make sure that particular table is not temporary table for
>> example. This is not a problem for USA Pgpool-II because it sends all
>> queries to usaserver.com anyway.
>>
>> However, this is a problem for Asia Pgpool-II, because it sends queries
>> to USA server across the ocean, which may be slow.  If you are sure
>> that you are not using temp tables, you can disable the query by
>> setting "check_temp_table = off". Same thing can be said to
>> "check_unlogged_table".
>>
>> Also Pgpool-II keeps internal cache to reduce issuing such that
>> queries. If you access many tables you might want to increase
>> "relcache_size".
>>
>> Best regards,
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese:http://www.sraoss.co.jp
>>
>> > Hi,
>> >
>> > New to the list and have been busy setting up pgpool-ii this last week or
>> > two.
>> >
>> > I've previously used drbd/slony for replication but pgpool looked like a
>> > good choice, so i'm trying it!
>> >
>> > I am wondering if it is possible to have pgpool-ii run across servers far
>> > apart (different countries):
>> >
>> > I have postgresql streaming replication working, from my USA to my Asia
>> > server and it seems ok.
>> >
>> > However i want pgpool to be used to automatically send reads to the Asia
>> > server and writes to the USA server for users in Asia.
>> >
>> > Ideally I want:
>> > - Master in the USA with pgpool-ii - with a webserver that will serve
>> most
>> > of the world, reads/writes are local
>> > - Slave in Asia with pgpool-ii - wtih a webserver that will server reads
>> > from Asia/Slave and send writes to the Master
>> > - Both servers only have public ip's
>> > - For the Master/USA server, i'm happy for all reads/writes to go to the
>> > Master.
>> > - For the Slave/Asia server I would like pgpool-ii to proxy database
>> > requests - sending writes to the USA server and doing reads from the Asia
>> > server....
>> >
>> > *In this situation I don't think i need a 'virtual ip' (i'm not trying to
>> > load balance USA requests). Is this correct?*
>> >
>> > Is this setup even possible?
>> >
>> > Thanks in advance.
>> >
>> > Jon
>>