Synch Replication - Synch rep 0114

From: "Patil, Smita (NSN - IN/Bangalore)" <smita(dot)patil(at)nsn(dot)com>
To: "Fujii Masao" <masao(dot)fujii(at)gmail(dot)com>
Cc: "PostgreSQL-development" <pgsql-hackers(at)postgresql(dot)org>, "K, Niranjan (NSN - IN/Bangalore)" <niranjan(dot)k(at)nsn(dot)com>
Subject: Synch Replication - Synch rep 0114
Date: 2009-01-30 11:05:12
Message-ID: F475619F97187B4182AC489DBD03D52B04C5F45D@inbhexc001.nsn-intra.net
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Hi,
I have been testing in recent, the Synch Replication(Synch rep 0114
<http://wiki.postgresql.org/wiki/Image:Synch_rep_0114.tgz> (Jan 14,
2009) ) on PostgreSQL version 8.4 (
postgresql-8.4devel_20081229.tar.bz2
<http://yum.pgsqlrpms.org/srpms/8.4/postgresql-8.4devel_20081229.tar.bz2
> )
I followed the steps in Readme as well used the test script provided in
patch for the setup.
As per wiki, I am able to bring up the walsender and the walreceiver
process in a single server as well when primary and seconday are setup
on different nodes(making necessary changes to the test script)

Then I am able to see the walsender and walreceiver process are in
progress.

Then I try to insert some records into the table created (within the
script) as below:
./psql
psql (8.4devel)
Type "help" for help.

postgres=# insert into temp values(5,'e');

I get the following output :
Standby 6820 FATAL: unexpected EOF on replication connection: lost
synchronization with server: got message type "c", length -805175295

Primary 6821 LOG: unexpected EOF on replication connection
Primary 6821 LOG: replication done at: write 0/1000000 (file
000000010000000000000000), flush 0/1000000 (file
000000010000000000000000)
Standby 6820 LOG: replication done at: write 0/1000000 (file
000000010000000000000000), flush 0/1000000 (file
000000010000000000000000)
Standby 6812 LOG: could not open file
"pg_xlog/000000010000000000000001" (log file 0, segment 1): No such file
or directory
Standby 6812 LOG: redo done at 0/4A983C
Standby 6812 PANIC: could not open file
"pg_xlog/000000010000000000000000" (log file 0, segment 0): No such file
or directory
Standby 6809 LOG: startup process (PID 6812) was terminated by signal
6: Aborted
Standby 6809 LOG: aborting startup due to startup process failure
INSERT 0 1

After this, I see both walsender and walreceiver are down and writer
process is still running.
Is this because, there is no provision of replication between primary
and secondary?
Or is it because write transactions are not supported?

In case where primary and standby are run on two different nodes, I am
able to bring up the walsender and walreceiver process.
But atleast read transactions( records inserted in primary ) are not
getting reflected in the standby node.

In such cases I would like to know about what exact features are working
with this patch?
Because, in the Readme section of Synch Replication wiki, it is
mentioned to check whether the walsender and walreceiver process are in
progress.
How about replication and read - write transactions?

Also with the latest patch Synch rep 0128
<http://wiki.postgresql.org/wiki/Image:Synch_rep_0128.tgz> (Jan 28,
2009), Am getting compilation errors.
Please let me about the correct status of the Synch Replication about
what features are working properly.

Regards,
Smita Patil


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