Re: How to replay a transaction log from the begining


Boxuan Li
 

Hi Ojas,

Ideally, by using Instant.now() to add your log processor, you should be able to see your callback invoked as soon as the transaction completes (if you are using a single in-memory storage backend), or with a minimal delay (depending on the read latency of your storage backend).

The time difference in your log looks a bit weird to me. Can you check if there is a clock drift among your servers?

Best,
Boxuan

「ojas.dubey via lists.lfaidata.foundation <ojas.dubey=amdocs.com@...>」在 2021年6月30日 週三,下午10:12 寫道:

Hi Boxuan,

Thanks. This indeed helped. Initially nothing happened (or at least it appeared that way) so I changed the start time to EPOCH and left the application running for a while and after sometime the callback was executed. 

So I was wondering how the log processor uses the start time value to replay the log and why did it take a long time to replay the logs. Is there a way by which I can reduce the time by setting the correct UTC time to start time (as i dont want to use EPOCH everytime) so that the callback is executed immediately?

Also is there a difference in the values of Instant.now() used by ReadMarker vs the actual local time used by the applicatioon because the ReadMarker initialization logs showed a different time. e.g.

2021-06-30T13:21:32.003+05:30 INFO |InternalEventLogger|||||||o.j.diskstorage.log.kcvs.KCVSLog|Loaded identified ReadMarker start time 2021-06-30T04:00:00Z into org.janusgraph.diskstorage.log.kcvs.KCVSLog$MessagePuller@4051e47b
2021-06-30T13:21:32.008+05:30 INFO |InternalEventLogger|||||||o.j.diskstorage.log.kcvs.KCVSLog|Loaded identified ReadMarker start time 2021-06-30T04:00:00Z into org.janusgraph.diskstorage.log.kcvs.KCVSLog$MessagePuller@6a332fb7
2021-06-30T13:21:32.013+05:30 INFO |InternalEventLogger|||||||o.j.diskstorage.log.kcvs.KCVSLog|Loaded identified ReadMarker start time 2021-06-30T04:00:00Z into org.janusgraph.diskstorage.log.kcvs.KCVSLog$MessagePuller@1f2cf847
2021-06-30T13:21:32.015+05:30 INFO |InternalEventLogger|||||||o.j.diskstorage.log.kcvs.KCVSLog|Loaded identified ReadMarker start time 2021-06-30T04:00:00Z into org.janusgraph.diskstorage.log.kcvs.KCVSLog$MessagePuller@3cc2c61b

while the application log shows another time

2021-06-30T13:26:15.794+05:30 INFO |InternalEventLogger||c.a.o.s.b.s.i.Test|Started tx standardjanusgraphtx[0x39c4068c] for requestId 5ba073c8-68c2-4356-8097-2e62ef56299a and batchId 9632dceb-7996-4464-91d8-1b157fc8ca00


Regards,
Ojas 

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