Howto recreate the transactionlog?

[Former Member]

Hello,

we are searching for a method for recreating the transaction log in case of

loss or corruption.

We have tried "util_execute clear log", but this did not work.

The mirroring of log volumes is no option for us because of the performance

impact.

We use MaxDB 7.5 Build 44 on Solaris.

Regards,

Stefan Schreyer

[roland_mallmann]

Hi Stefan,

can you please be a bit more exact in what you mean with <i>"recreating the transaction log in case of loss or corruption"</i> and <i>"We have tried "util_execute clear log", but this did not work"</i>.

The 'clear log' command should recreate the physical log volume, but what kind of error messages did you get during your tests?

Regards,

Roland

[Former Member]

Hi,

when one or more log volumes are lost or corrupt then maxdb will do a emergency

shutdown.

The "normal way" to reanimate the database will be a full restore with

(incomplete) recovery using the available autolog files.

If you have a very large database (e.g. 500 GB) this will take a long, long time.

In terms of service level agreements this is no option.

So there must be a command to recreate the log volumes like RESETLOGS

or something.

We tried the util command "util_execute clear log" in an util session within

dbmcli.

We got the following error:

ERR

-24988,ERR_SQL: sql error

-8888,connection broken server state 4

In the error log we can see:

ERR 20014 IOMan Attach error on log volume 1: Could not open volume

in both cases: lost log volumes or corrupted log volumes.

Sounds to me that "clear log" only succeeds if the log volumes are

available and not corrupt.

Regards,

Stefan

[roland_mallmann]

Hi Stefan,

with MaxDB versions < 7.7.02 Build 06, the 'clear log' command will <b>not</b> recreate the physical logvolume, but 'only' initialize the logvolume if it is both available and not corrupted.

I did my first test with MaxDB version 7.7.03, which worked as described, but in 7.5 I get similar errors, as expected.

I can check back with the specific developers to see what's still possible to be implemented in 7.5 or 7.6, but I'm afraid I can't promise you anything.

Regards,

Roland