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Negative "insert free space" on DOL pages

Nov 15, 2016 at 08:57 AM

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Hi

Recently, I performed re-materialization of ASE-to-ASE replication with SAP Replication Server using dump marker and the connection to the replicate ASE started to fail from time to time with error 1157 - "insert free space in page header of DOL page is incorrect". After resuming of the connection once or maximum twice, the replication starts working again. I checked the "insert free space" on affected pages and it is indeed negative. Also, I tried to submit a problematic statement from the queue manually, but it (an INSERT) works without problem. It appears that "insert free space" is negative in the primary database two.

I have two questions:

a. How to fix "insert free space" without rebuilding of a table? The table in question is quite big and I didn't succeed to solve the problem by dbcc tablealloc with fix.

b. It is interesting that only RS, and none of my customer's applications, get errors 1157. What is special with the RS connection? May the problem expand to additional applications in the future?

Thanks in advance

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Forgot to mention product versions:

ASE 15.7 ESD#4.2

RS 15.7 SP 120

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Some general ramblings that may (not) apply ...

- How did you confirm the negative free space setting? (More of a curiosity question; dbcc checkstorage? dbcc page? something else?)

- Wondering if the application isn't complaining because a) the app ignores Msg 1157 (generally an informational message) or b) application isn't hitting the problematic page (less likely if PDB and RDB are mirror images based on recent resync).

- Assuming dbcc checkstorage is reporting the issue, too ... then per Bret's write up (checkstorage fault 100034), if dbcc tablealloc/fix isn't addressing the issue then perhaps open a case with tech support?

- From a repserver perspective, and assuming the 1157's really are informational in nature (and in fact the issue is fixed on-the-fly), have you tried configuring the errorclass to ignore (or retry) the txn when a 1157 occurs? If you configure the error for retry, and configure a retry count of, say 5, that should be enough to fix the informational/transient 1157's but still flag a more serious 1157 (if such a thing exists) by shutting down the DSI.

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Hi Mark

I confirm negative values for "insert free space" using "dbcc page". Even more, the value remains the same (and negative) after recalculation of the "insert free space", as reported by error message 1157. I don't care about the replication too much because the problem can be easily worked around by using of a custom error class, as you mentioned, or just by plain resuming of the connection every number of minutes. My main concern is that if the replication suffers from this problem, other applications may also start suffering from it at some unknown point. Actually, I don't really understand why RS is affected and others don't. I can't find an information about similar cases anywhere, it seems that the error 1157 is rather infrequent. Probably, my customer will have to open a support call.

Thanks
Leonid

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