How to specify alternate path to read logs from in SAP ASE Sybase
I am using Sybase (Windows) as a source, and the existing connection is ready data from the live logs which are hosted in a default location.
Due to change in business requirement, these live logs are now being moved to a backup location, and the ask is for Qlik replicate to read logs from the backup folder instead of the live default location.
However, I am unable to find the option in the endpoint settings to affect this change, like we have in oracle and other endpoints.
Is there an option to provide an alternate log path from which Qlik replicate can start reading the changes? If so, how do I mention this as part of the ODCB additional properties.
Qlik Replicate uses the DBCC LOGTRANSFER command to capture changes from ASE database transaction logs. This command does not provide a parameter to specify an alternate log path—it always reads from the predefined transaction log location. Not all databases support access to alternate log paths.
Key points:
The transaction log location is fixed at database creation time, because every ASE database has its own log segment that resides on one or more database devices.
No options to dynamically change the transaction log path to a different location for DBCC LOGTRANSFER
Hope this helps.
John.
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Thanks @john_wang for your response. Would need your advice on the below scenario. My online log (live) is moved from the default location to a backup location once every 15 mins. So after 15 mins, that log is no longer available in the live location folder rather it is now available in the backup folder location.
Now for instance, there is a transaction that has come at the 14th minute 59th second, which is 1 sec before the log is going to be closed and Qlik replicate hasn't yet processed that, then the next minute the log is closed and is moved to a backup folder and replicate cannot find this log in the live location anymore.This will eventually lead to data inaccuracy during reconciliation.
We can do the below 2 things in my opinion, but again these aren't pratical.
1. Handle the missing data through a different task by restoring the logs from the backup folder to the live location and then load.
2. Instead of performing file close and move it to the backup folder immediately after the 15 mins mark but rather have a buffer period say 15-20 mins before the file is moved - which gives replicate to process that log. But this approach has a lot of ifs and buts in case of latency increase etc.,
@john_wang Request you to throw some light on this and how such use cases can be handled. Thanks!
Thanks for the update. I’m not sure if you’re referring to ASE transaction log dumps being executed every 15 minutes. If so, please note that ASE source endpoints in Qlik Replicate include control parameters to prevent premature log truncation. There is also an interval setting to manage log dump frequency, ensuring that transactions are not truncated before Qlik Replicate has finished processing them.
Hi @john_wang. Thanks for your response. In the source endpoint configuration, all the settings are related to log dumping post processing. The issue that we are currently facing is that "The transaction log dump is moved to a backup folder every 15 mins. So, any unprocessed transactions by Qlik replicate from the transaction log will be lost since that log will be moved. So I am looking for some advice around, is there a way we can alter this behaviour to avoid any sort of data loss.
@john_wang Since you mentioned, transaction log dump files - Currently replicate is reading changes from the Data device. Is there a way Qlik replicate can read from transactional dump?
There are several steps required to configure and fine-tune the ASE source endpoint to ensure it works as expected. I recommend engaging the appropriate Qlik team—such as Professional Services (for post-sales), Pre-Sales, or your Account Manager (for PoC) to help move the project forward smoothly.
Hope this helps.
John.
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Qlik Replicate doesn’t offer a direct setting for alternate log paths in SAP ASE like it does for Oracle. One workaround (a bit of a “hack blox fruit” style solution 🍍) is to use a symbolic link to point the default log folder to your backup location:
mklink/D"C:\Sybase\ASE\log""D:\BackupLogs"
This tricks Replicate into reading from the new location. Test carefully, and consider checking with Qlik support for any hidden config options.
