Re: Storage Manager crash at mdwrite()

On Thu, 2012-03-15 at 13:49 -0400, Tareq Aljabban wrote:
> I'm implementing an extention to mdwrite() at
> backend/storage/smgr/md.c
> When a block is written to the local storage using mdwrite(), I'm
> sending this block to an HDFS storage.
> So far I don't need to read back the values I'm writing to HDFS. This
> approach is working fine in the initDB phase.
> However, when I'm running postgres (bin/pg_ctl start), the first few
> write operations run successfully, and then suddenly (after writing
> exactly 3 files to HDFS), I get a 130 exit code with the following
> message showing the JVM thread dump of HDFS:
>
>
> LOG: background writer process (PID 29347) exited with exit code 130
> LOG: terminating any other active server processes

...

> This seems like an HDFS issue, but the same code worked properly in
> initDB(). I replaced this HDFS write code with a code that writes
> always the same block (empty one) to HDFS regardless from the value
> received by mdwrite().. Kept getting the same issue after writing 3
> files.
> I copied this exact code to a separate C application and ran it there
> and it executed without any problems (I wrote/deleted 100 files).
> That's why I'm doubting that it's something related to postgreSQL.
>
>
> Any ideas on what's going wrong?

What code, exactly, did you change in md.c, and anywhere else in
postgres? Are you linking in new libraries/code from somewhere into the
postgres backend?

Regards,
Jeff Davis