Re: [Exist-open] existdb errors on xQueries

[Joe W. <jo...@gm...>]

Hi Seena,

I'm not certain that the errors you shared indicate data corruption. Seeing
the full stack trace of the error in your initial post in this thread would
help.

The primary cause of database corruption is improper shutdown. This is
typically fixed automatically when next starting eXist, since it detects an
unclean shutdown by the presence of lock files and triggers a reindex. If
this built-in process is not successful, you can perform the emergency
recovery technique of creating a backup and restoring from the backup. This
is documented here:

  https://exist-db.org/exist/apps/doc/backup#emergency-export-tool

Proactively performing backups - via a scheduled job, for example - allows
you to expedite this process by restoring from a recent backup, rather than
needing to perform the backup upon a possibly corrupted database.

Best,
Joe

On Thu, Jun 12, 2025 at 5:29 AM Sanil, Seena via Exist-open <
exi...@li...> wrote:

> Thanks Michael W.
>
>
>
> Currently we are reindexing the entire collection.  For future, we would
> like to know if there is a way to avoid data/collection being corrupted ?
> If it gets corrupted, what is the best way to fix it?
>
>
>
> Thanks
>
> Seena
>
>
>
> *From: *Michael Westbay <wes...@ja...>
> *Date: *Tuesday, June 10, 2025 at 7:52 PM
> *To: *Sanil, Seena <ss...@bl...>
> *Cc: *eXist DB ML <exi...@li...>, Mulvaney, Michael <
> MMu...@bl...>, Lubey, Brian <
> bl...@bl...>
> *Subject: *Re: [Exist-open] existdb errors on xQueries
>
> *CAUTION:* *This email originated from outside of the organization. Do
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>
>
> Hi Seena,
>
>
>
> The return type error is an easy one to fix. The function declaration
> expects to always return 1 and only 1 configuration. But it is getting none.
>
>
>
> If returning no configuration is an option, redefine the function as:
>
>
>
> ```xquery
>
> declare function config:get-configuration() as element(configuration)? {
>
>   ...
>
> };
>
> ```
>
>
>
> If it should always return a configuration, then you need to determine why
> it is not finding the configuration. Since you aren't passing a parameter
> into the function, it doesn't appear to be something on a per-user basis --
> so there should always be the global configuration.
>
>
>
> Hope this helps point you in the right direction.
>
>
>
> Take care.
>
>
>
>
>
>
>
>
>
>
>
> 2025年6月10日(火) 22:08 Sanil, Seena via Exist-open <
> exi...@li...>:
>
> Also errors like this “
>
> exerr:*ERROR* The actual return type does not match the sequence type
> declared in the function's signature: config:get-configuration() as
> element(configuration). Expected cardinality: exactly one, got 0. [at line
> 42, column 42, source: /db/apps/eXide/controller.xq]\nIn
> function:\n\tconfig:get-configuration() as element(configuration)”
>
>
>
> *From: *Sanil, Seena <ss...@bl...>
> *Date: *Monday, June 9, 2025 at 7:44 PM
> *To: *eXist DB ML <exi...@li...>
> *Cc: *Lubey, Brian <bl...@bl...>, Mulvaney, Michael <
> MMu...@bl...>
> *Subject: *existdb errors on xQueries
>
> Hello,
>
> We are getting some errors while running xQuery’s  all at once against
> our eXist database with 1.3 million files from different clients like
> browser, oxygen desktop, Postman.
>
>
>
> The errors are “Error while processing /exist/xmlrpc: An unknown error
> occurred: org.apache.xmlrpc.XmlRpcException: I/O error while processing
> request”. . After that, the existdb instance hosted in the the cloud is
> not coming up. Is there a reason for this behavior? How do we avoid this in
> the future?
>
>
>
> The xQuery we used are :
>
> _query=//cite.bna.reference&_howmany=1000 , on a collection
>
>
>
> Thanks
>
> Seena Sanil
>
>
>
>
>
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>
> --
>
> Michael Westbay
> Writer/System Administrator
> http://www.japanesebaseball.com/
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