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Thread Verfy table showing issue with checksum
Fri, Jan 18 2019 6:51 PMPermanent Link

David

Hi Tim/All.

I have just done a Verify table using DBSys and a couple of tables have come back with checksum errors.

I repaired the tables and it seems to have fixed it which is great but I would like some assurance that dong this is not going to delete any data, and if it does, at least will this be reported in the output.  I wouldn't like to lose data and now know about it until a user asks where their data has gone.

Also I noticed that by going to the record number in the table identified by the Verify Table and making a change to that record and posting it seems to also fix the error.  Is this correct or am I just imagining it?

Regards
David.
Tue, Jan 22 2019 11:19 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

David,

<< I have just done a Verify table using DBSys and a couple of tables have come back with checksum errors.

I repaired the tables and it seems to have fixed it which is great but I would like some assurance that dong this is not going to delete any data, and if it does, at least will this be reported in the output.  I wouldn't like to lose data and now know about it until a user asks where their data has gone. >>

Are you using the DBISAM Database Server, or just local sessions directly connected to the database(s) ?  If the latter, then it's certainly possible that a disconnection could cause an incomplete write, although record checksum errors are pretty rare in such cases (they're pretty rare, in general, for architectural reasons).

The repair process in DBISAM never deletes any records unless the record is causing an integrity issue with any primary or secondary indexes.  In such a case, the removal of the record is logged in the repair messages along with the reason why.

<< Also I noticed that by going to the record number in the table identified by the Verify Table and making a change to that record and posting it seems to also fix the error.  Is this correct or am I just imagining it? >>

Yes, updating the record will fix the record checksum

Tim Young
Elevate Software
www.elevatesoft.com
Tue, Jan 22 2019 11:21 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

David,

Duh, I just realized that you're posting in the C/S area, so yeah, you're probably using the DBISAM Database Server.

If you see the issue with the checksums again, and there aren't any cases of the DBISAM Database Server being improperly shut down, then please let me know.  More than likely, there's an issue with the disk or something similar that is causing a problem.

Tim Young
Elevate Software
www.elevatesoft.com
Tue, Jan 22 2019 2:36 PMPermanent Link

David

Hi Tim.

Sure I will let you know if anything happens again in the future.  We have irregularly  server hands where it stops repsonding to any logins and I have no choice but to restart the server by restarting the service.  Could that be the cause of this?  

I think I have about 40 tables, some with upwards of 100,000 records in it and the only checksum errors amounted to no more than 6 in any one table.

Regards
David.

Tim Young [Elevate Software] wrote:

David,

Duh, I just realized that you're posting in the C/S area, so yeah, you're probably using the DBISAM Database Server.

If you see the issue with the checksums again, and there aren't any cases of the DBISAM Database Server being improperly shut down, then please let me know.  More than likely, there's an issue with the disk or something similar that is causing a problem.

Tim Young
Elevate Software
www.elevatesoft.com
Tue, Jan 22 2019 2:41 PMPermanent Link

David

Could do with an edit button Tim, that should have been server hangs!

Also in my haste to reply I should clarify, in 40 odd tables, only 4 tables had any issues and one of them witj upwards of 100k records only reported 6 errors at most.
Tue, Jan 29 2019 10:38 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

David,

<< Sure I will let you know if anything happens again in the future.  We have irregularly  server hands where it stops repsonding to any logins and I have no choice but to restart the server by restarting the service.  Could that be the cause of this?   >>

You're seeing hangs with the latest 4.47, or is it an older version ?

Tim Young
Elevate Software
www.elevatesoft.com
Tue, Jan 29 2019 2:57 PMPermanent Link

David

Hi Tim.

Its an older version 4.25 which I plan to update to 4.47 sometime this year hopefully.

Tim Young [Elevate Software] wrote:

You're seeing hangs with the latest 4.47, or is it an older version ?

Tim Young
Elevate Software
www.elevatesoft.com
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