Re: [Exist-open] IOException: not a data-page

[Wolfgang M. <wol...@gm...>]

> I am using 20051203 snapshot on MAC OS X 10.4.3.
> I stored 10 xml documents and the related xsl, xql files
> in the same collection.
> After I performed heavy load test (using web stress tool),
> I got Out of Memory error. I manually killed eXist process
> (bin/shutdown.sh didn't work) and restarted it, then
> I got the IOException.
>
> My questions are as follows:
>
> 1. Does Out of Memory error usually cause such IOException?

eXist supports crash recovery, so ideally the server should detect the
crash and launch a recovery run to bring the db back into a consistent
state. However, the recovery mechanism sometimes seems to fail if the
crash was caused by an OutOfMemory error. I still have to find out
why. The January snapshot has one or two bug fixes concerning recovery
failures and addresses the out of memory issues (at least in part).

> 2. When Out of Memory error occurs, how can I handle it?
> (just wait until GC completes or explicitely kill it or else?)

Kill it. If you are sure you did not make any changes to the db within
the last few minutes, remove the .log files from webapp/WEB-INF/data,
then restart (removing the .log files avoids a recovery run).

> 3. How can I restore the database?

For cases like these, you should use eXist's backup/restore tools to
create a backup from time to time.

Wolfgang