Re: intermittent long "log file sync" waits

From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Sun, 2 Feb 2020 01:28:50 -0500
Message-ID: <7d41a1e0-22f6-0bca-e2c7-da793259471c_at_gmail.com>


And some bugs, too. Race condition between LGWR slaves are not out of the question:

Bug 21915719 - 12c Hang: LGWR waiting for 'lgwr any worker group' or ORA-600 [kcrfrgv_nextlwn_scn] ORA-600 [krr_process_read_error_2] on IBM AIX / HPIA (Doc ID 21915719.8)

Bug 9916044: ALOT OF LOG FILE SYNC AFTER APPLYING 11.1.0.7.3 This bug 9916044 suggest to apply latest PSU. So I would recommend you to apply the latest PSU patch on 11.1.0.7 which is 9952228 - 11.1.0.7.5 Patch Set Update (PSU)

Of course, there is also a cryptic message "Private strand flush not complete" Long story short, if there are many "log file sync" events and you think they shouldn't be present in such number, please open performance case with Oracle support. And while it is true that "log file sync" doesn't measure only I/O, it mostly depends on I/O.

On 2/1/20 10:50 PM, Tanel Poder wrote:
> But in 12c there are more moving parts.

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217

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Received on Sun Feb 02 2020 - 07:28:50 CET

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