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Archive for October, 2010

Looking for libpq.so.4

October 13, 2010 2 comments

I had always been building Slony from source, but for the first time I tried using the community version from “pgrpms.org”. I was using PostgreSQL version 8.3 so it was really easy to find the correct rpms at http://www.pgrpms.org/8.3/redhat/rhel-5-x86_64/ but as I tried installing Slony package I was hit with an error:

"libpq.so.4 not found"

This looked really weird to me as I already had the libpq library installed as libpq.so.5 but it was still looking for libpq.so.4.

Looking for a solution I started going through the 8.3 RPMs and tried looking for file libpq.so.4 file…. bingooo!!! I found one which had it. compat-postgresql-libs was the answer to this problem.

After installing that package, Slony got installed successfully without any problems.

Shoaib Mir
shoaibmir[@]gmail.com

Categories: PostgreSQL Tags: , ,

(SLONY) cache lookup failed for type

October 13, 2010 1 comment

Just been away from blogging for quite a while now as work had been keeping me extremly busy but finally got sometime today to blog about an interesting problem I saw with Slony yesterday…

While at a customer site, I upgraded them to Slony version 1.2.21 and also during the process re-initialized the cluster. The whole process was done without any problem but right after everything was synched across, one of the Sysadmins saw this error in the database server log file:

"cache lookup failed for type 27889"

On doing an INSERT into sl_log_1 table.

Having never seen such a problem before with Slony, it got me a little worried as this was a production database so we had to fix it very quickly.

After doing a little bit of research found out that, by simply restarting the application server which is making connections to the database server will solve the problem. Reason being, the application server had already established a connection to database when we were dropping and re-creating the cluster and that is why it was still looking for old values  that were sitting in the cache. Once we restarted the application server, it was all fine.


Shoaib Mir
shoaibmir[@]gmail.com