Oracle DB with lots of XA Tx

From: Venkat Krish <venkat.lear_at_gmail.com>
Date: Mon, 3 Aug 2015 15:47:40 -0400
Message-ID: <CAOV8h7v7Kq3jWm4ZiANfDDjRn2fVteCo=O2w-uqXfZqsmVyA5g_at_mail.gmail.com>



Dear Oracle Smart-ians.

Background:

Running Oracle 11.2.0.4 running on Solaris 10. ( beefy box with 100+ cores & running many dbs in same server..dont ask me why)

Problem:

In one of our critical DBs during peak activity, we see the top activity "latch free" dominated.

  • top event shows 85% latch free
    > Event Waits Total Wait Time (sec) Wait Avg(ms) % DB time Wait
    > Class
    > ----------- ----------- -------------- ------------ ---------
    > -----------
    > latch free 4,884,174 376.5K 77 84.5 Other

*& looking at latch statistics*
> Latch Name Get Requests Pct Get Miss Avg Slps /Miss
> Wait Time (s) NoWait Requests
> ----------------------------- ------------ ------------ --------------
> ------------- --------------- ----------------
> transaction branch allocation 56,706,998 48.17 0.18
> 376221 0

we do know, the application might be abusing XA transactions & things could be done better either with more statements in same transaction or trying loosely coupled etc.
But our hands are tied and application cannot be touched.

So the question is..Is there any configuration or parameter that can be tweaked on the db end just to see if it makes reduces the time it spends on "transaction branch allocation".?

Thanks in adv,
Venkat

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Received on Mon Aug 03 2015 - 21:47:40 CEST

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