IDS Forum

Re: Fast recovery slow

Posted By: MARK SCRANTON
Date: Thursday, 18 February 2016, at 3:57 p.m.

In Response To: Fast recovery slow (ROGER VILCA)

Roger -

This behavior is typical if the engine dies with heavy tx's taking place. It can typically be two things: 1) a result of transactions being rolled forward that just takes a long time due to activity. But then it's possible that transactions are now being rolled back since they were not committed. 2) you're stuck in fast recovery since "physical log overflow" occurred. Less likely in later versions of the engines since the you have the oppty to set PLOG_OVERFLOW_PATH to a file on disk in case the plog wraps. This helps avoid getting stuck in fast recovery due to overflow but can be VERY slow since it's simply reading through pages on disk. (Unlike the logical logs, if the phys log wraps all the way around, we keep writing pages, and yes, have just overwritten pages needed for recovery. Thus the PLOG_OVERLOW_PATH config param.) The default for this I believe is $INFORMXDIR/tmp, which may or may not have enough room for a bad overflow.

Either way, check your msg log for: 1) logical logs being walked through during fast recovery. You'll see them increment over time. 2) transactions being rolled back. 3) "physical log overflow has occurred" - if the engine died after this occured, you could be stuck in fast recovery and it'll never end.

Since we don't see getting stuck in fast recovery as much as back in the day, I'd be curious to hear others weigh in on this too with 11.7+.

If you'll send your msg log (or post part of it here) I'd interrogate it for the different behaviors I described above.

Thanks -
Mark Scranton
The Mark Scranton Group
mark@markscranton.com
765-729-2601

Messages In This Thread

• Fast recovery slow
  ROGER VILCA -- Tuesday, 9 February 2016, at 8:43 p.m.
  • Re: Fast recovery slow
    MARK SCRANTON -- Thursday, 18 February 2016, at 3:57 p.m.
    • Re: Fast recovery slow
      ROGER VILCA -- Monday, 22 February 2016, at 11:49 a.m.
      • Re: Fast recovery slow
        MARK SCRANTON -- Monday, 22 February 2016, at 2:33 p.m.
        • Re: Fast recovery slow
          John Miller iii -- Monday, 22 February 2016, at 3:53 p.m.

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