Hi.

I have this problem:

I have PostgreSQL 9.1.3 and the last night crash it.

This was the first error after an autovacuum (the night before last):

<2012-06-06 00:59:07 MDT 814 4fceffbb.32e
"dbRX"
<2012-06-06 01:05:26 MDT 1854 4fc7d1eb.73e
directory
<2012-06-06 01:05:28 MDT 1383 4fcf0136.567 >ERROR: tuple concurrently updated
<2012-06-06 01:05:28 MDT 1383 4fcf0136.567 >CONTEXT: automatic vacuum of table "global.pg_catalog.pg_attrdef"
<2012-06-06
01:06:09 MDT 1851 4fc7d1eb.73b >ERROR: xlog flush request
4/E29EE490 is not satisfied --- flushed only to 3/13527A10
<2012-06-06 01:06:09 MDT 1851 4fc7d1eb.73b >CONTEXT: writing block 0 ofrelation base/311360/12244_vm
<2012-06-06
01:06:10 MDT 1851 4fc7d1eb.73b >ERROR: xlog flush request
4/E29EE490 is not satisfied --- flushed only to 3/13527A10
<2012-06-06 01:06:10 MDT 1851 4fc7d1eb.73b >CONTEXT: writing block 0 ofrelation base/311360/12244_vm
<2012-06-06 01:06:10 MDT 1851 4fc7d1eb.73b >WARNING: could not write block 0 of base/311360/12244_vm
<2012-06-06 01:06:10 MDT 1851 4fc7d1eb.73b >DETAIL: Multiple failures --- write error might be permanent.


Last night it was terminated by signal 6.

<2012-06-07 01:36:44 MDT 2509 4fd05a0c.9cd >LOG: startup process (PID 2525) was terminated by signal 6: Aborted
<2012-06-07 01:36:44 MDT 2509 4fd05a0c.9cd >LOG: aborting startup due to startup process failure
<2012-06-07
01:37:37 MDT 2680 4fd05a41.a78 >LOG: database system shutdown
was interrupted; last known up at 2012-06-07 01:29:40 MDT
<2012-06-07
01:37:37 MDT 2680 4fd05a41.a78 >LOG: could not open file
"pg_xlog/000000010000000300000013" (log file 3, segment 19): No such
file or directory
<2012-06-07 01:37:37 MDT 2680 4fd05a41.a78 >LOG: invalid primary checkpoint record

And the only option was pg_resetxlog.

After this a lot of querys showed me this error:
<2012-06-07 09:24:22 MDT 1306 4fd0c7a6.51a >ERROR: missing chunk number0 for toast value 393330 in pg_toast_2619
<2012-06-07 09:24:31 MDT 1306 4fd0c7a6.51a >ERROR: missing chunk number0 for toast value 393332 in pg_toast_2619

I lost some databases.

I restarted the cluster again with initdb and then I restored the databases that I could backup (for the other I restored an old backup)

no space or permissions problem. No filesystem or disk error.

Can you help me to know what happened?

Thanks and regards...