log file sync 诊断脚本

文档 ID 1064487.1) log file sync 诊断

脚本内容如下：

-- NAME: LFSDIAG.SQL

-- ------------------------------------------------------------------------

-- AUTHOR: Michael Polaski - Oracle Support Services

-- ------------------------------------------------------------------------

-- PURPOSE:

-- This script is intended to provide a user friendly guide to troubleshoot

-- log file sync waits. The script will look at important parameters involved

-- in log file sync waits, log file sync wait histogram data, and the script

-- will look at the worst average log file sync times in the active session

-- history data and AWR data and dump information to help determine why those

-- times were the highest. The script will create a file called

-- lfsdiag_<timestamp>.out in your local directory.

set echo off

set feedback off

column timecol new_value timestamp

column spool_extension new_value suffix

select to_char(sysdate,'Mondd_hh24mi') timecol,

'.out' spool_extension from sys.dual;

column output new_value dbname

select value || '_' output

from v$parameter where name = 'db_name';

spool lfsdiag_&&dbname&×tamp&&suffix

set trim on

set trims on

set lines 140

set pages 100

set verify off

alter session set optimizer_features_enable = '10.2.0.4';

PROMPT LFSDIAG DATA FOR &&dbname&×tamp

PROMPT Note: All timings are in milliseconds (1000 milliseconds = 1 second)

PROMPT

PROMPT IMPORTANT PARAMETERS RELATING TO LOG FILE SYNC WAITS:

column name format a40 wra

column value format a40 wra

select inst_id, name, value from gv$parameter

where ((value is not null and name like '%log_archive%') or

name like '%commit%' or name like '%event=%' or name like '%lgwr%')

and name not in (select name from gv$parameter where (name like '%log_archive_dest_state%'

and value = 'enable') or name = 'log_archive_format')

order by 1,2,3;

PROMPT

PROMPT ASH THRESHOLD...

PROMPT

PROMPT This will be the threshold in milliseconds for average log file sync

PROMPT times. This will be used for the next queries to look for the worst

PROMPT 'log file sync' minutes. Any minutes that have an average log file

PROMPT sync time greater than the threshold will be analyzed further.

column threshold_in_ms new_value threshold format 999999999.999

select min(threshold_in_ms) threshold_in_ms

from (select inst_id, to_char(sample_time,'Mondd_hh24mi') minute,

avg(time_waited)/1000 threshold_in_ms

from gv$active_session_history

where event = 'log file sync'

group by inst_id,to_char(sample_time,'Mondd_hh24mi')

order by 3 desc)

where rownum <= 10;

PROMPT

PROMPT ASH WORST MINUTES FOR LOG FILE SYNC WAITS:

PROMPT

PROMPT APPROACH: These are the minutes where the avg log file sync time

PROMPT was the highest (in milliseconds).

column minute format a12 tru

column event format a30 tru

column program format a40 tru

column total_wait_time format 999999999999.999

column avg_time_waited format 999999999999.999

select to_char(sample_time,'Mondd_hh24mi') minute, inst_id, event,

sum(time_waited)/1000 TOTAL_WAIT_TIME , count(*) WAITS,

avg(time_waited)/1000 AVG_TIME_WAITED

from gv$active_session_history

where event = 'log file sync'

group by to_char(sample_time,'Mondd_hh24mi'), inst_id, event

having avg(time_waited)/1000 > &&threshold

order by 1,2;

PROMPT

PROMPT ASH LFS BACKGROUND PROCESS WAITS DURING WORST MINUTES:

PROMPT

PROMPT APPROACH: What is LGWR doing when 'log file sync' waits

PROMPT are happening? LMS info may be relevent for broadcast

PROMPT on commit and LNS data may be relevant for dataguard.

PROMPT If more details are needed see the ASH DETAILS FOR WORST

PROMPT MINUTES section at the bottom of the report.

column inst format 999

column minute format a12 tru

column event format a30 tru

column program format a40 wra

select to_char(sample_time,'Mondd_hh24mi') minute, inst_id inst, program, event,

sum(time_waited)/1000 TOTAL_WAIT_TIME , count(*) WAITS,

avg(time_waited)/1000 AVG_TIME_WAITED

from gv$active_session_history

where to_char(sample_time,'Mondd_hh24mi') in (select to_char(sample_time,'Mondd_hh24mi')

from gv$active_session_history

where event = 'log file sync'

group by to_char(sample_time,'Mondd_hh24mi'), inst_id

having avg(time_waited)/1000 > &&threshold and sum(time_waited)/1000 > 1)

and (program like '%LGWR%' or program like '%LMS%' or

program like '%LNS%' or event = 'log file sync')

group by to_char(sample_time,'Mondd_hh24mi'), inst_id, program, event

order by 1,2,3,5 desc, 4;

PROMPT

PROMPT HISTOGRAM DATA FOR LFS AND OTHER RELATED WAITS:

PROMPT

PROMPT APPROACH: Look at the wait distribution for log file sync waits

PROMPT by looking at "wait_time_milli". Look at the high wait times then

PROMPT see if you can correlate those with other related wait events.

column event format a40 wra

select inst_id, event, wait_time_milli, wait_count

from gv$event_histogram

where event in ('log file sync','gcs log flush sync',

'log file parallel write','wait for scn ack',

'log file switch completion','gc cr grant 2-way',

'gc buffer busy','gc current block 2-way') or

event like '%LGWR%' or event like '%LNS%'

order by 2 desc,1,3;

PROMPT

PROMPT ORDERED BY WAIT_TIME_MILLI

select inst_id, event, wait_time_milli, wait_count

from gv$event_histogram

where event in ('log file sync','gcs log flush sync',

'log file parallel write','wait for scn ack',

'log file switch completion','gc cr grant 2-way',

'gc buffer busy','gc current block 2-way')

or event like '%LGWR%' or event like '%LNS%'

order by 3,1,2 desc;

PROMPT

PROMPT REDO WRITE STATS

PROMPT

PROMPT "redo write time" in centiseconds (100 per second)

PROMPT 11.1: "redo write broadcast ack time" in centiseconds (100 per second)

PROMPT 11.2: "redo write broadcast ack time" in microseconds (1000 per millisecond)

column value format 99999999999999999999

column milliseconds format 99999999999999.999

select v.version, ss.inst_id, ss.name, ss.value,

decode(substr(version,1,4),

'11.1',decode (name,'redo write time',value*10,

'redo write broadcast ack time',value*10),

'11.2',decode (name,'redo write time',value*10,

'redo write broadcast ack time',value/1000),

decode (name,'redo write time',value*10)) milliseconds

from gv$sysstat ss, v$instance v

where name like 'redo write%' and value > 0

order by 1,2,3;

PROMPT

PROMPT AWR WORST AVG LOG FILE SYNC SNAPS:

PROMPT

PROMPT APPROACH: These are the AWR snaps where the average 'log file sync'

PROMPT times were the highest.

column begin format a12 tru

column end format a12 tru

column name format a13 tru

select dhs.snap_id, dhs.instance_number inst, to_char(dhs.begin_interval_time,'Mondd_hh24mi') BEGIN,

to_char(dhs.end_interval_time,'Mondd_hh24mi') END,

en.name, se.time_waited_micro/1000 total_wait_time, se.total_waits,

se.time_waited_micro/1000 / se.total_waits avg_time_waited

from dba_hist_snapshot dhs, wrh$_system_event se, v$event_name en

where (dhs.snap_id = se.snap_id and dhs.instance_number = se.instance_number)

and se.event_id = en.event_id and en.name = 'log file sync' and

dhs.snap_id in (select snap_id from (

select se.snap_id, se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and en.name = 'log file sync'

order by avg_time_waited desc)

where rownum < 4)

order by 1,2;

PROMPT

PROMPT AWR REDO WRITE STATS

PROMPT

PROMPT "redo write time" in centiseconds (100 per second)

PROMPT 11.1: "redo write broadcast ack time" in centiseconds (100 per second)

PROMPT 11.2: "redo write broadcast ack time" in microseconds (1000 per millisecond)

column stat_name format a30 tru

select v.version, ss.snap_id, ss.instance_number inst, sn.stat_name, ss.value,

decode(substr(version,1,4),

'11.1',decode (stat_name,'redo write time',value*10,

'redo write broadcast ack time',value*10),

'11.2',decode (stat_name,'redo write time',value*10,

'redo write broadcast ack time',value/1000),

decode (stat_name,'redo write time',value*10)) milliseconds

from wrh$_sysstat ss, wrh$_stat_name sn, v$instance v

where ss.stat_id = sn.stat_id

and sn.stat_name like 'redo write%' and ss.value > 0

and ss.snap_id in (select snap_id from (

select se.snap_id, se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and en.name = 'log file sync'

order by avg_time_waited desc)

where rownum < 4)

order by 1,2,3;

PROMPT

PROMPT AWR LFS AND OTHER RELATED WAITS FOR WORST LFS AWRs:

PROMPT

PROMPT APPROACH: These are the AWR snaps where the average 'log file sync'

PROMPT times were the highest. Look at related waits at those times.

column name format a40 tru

select se.snap_id, se.instance_number inst, en.name,

se.total_waits, se.time_waited_micro/1000 total_wait_time,

se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and (en.name in

('log file sync','gcs log flush sync',

'log file parallel write','wait for scn ack',

'log file switch completion','gc cr grant 2-way',

'gc buffer busy','gc current block 2-way')

or en.name like '%LGWR%' or en.name like '%LNS%')

and se.snap_id in (select snap_id from (

select se.snap_id, se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and en.name = 'log file sync'

order by avg_time_waited desc)

where rownum < 4)

order by 1, 6 desc;

PROMPT

PROMPT AWR HISTOGRAM DATA FOR LFS AND OTHER RELATED WAITS FOR WORST LFS AWRs:

PROMPT Note: This query won't work on 10.2 - ORA-942

PROMPT

PROMPT APPROACH: Look at the wait distribution for log file sync waits

PROMPT by looking at "wait_time_milli". Look at the high wait times then

PROMPT see if you can correlate those with other related wait events.

select eh.snap_id, eh.instance_number inst, en.name, eh.wait_time_milli, eh.wait_count

from wrh$_event_histogram eh, v$event_name en

where eh.event_id = en.event_id and

(en.name in ('log file sync','gcs log flush sync',

'log file parallel write','wait for scn ack',

'log file switch completion','gc cr grant 2-way',

'gc buffer busy','gc current block 2-way')

or en.name like '%LGWR%' or en.name like '%LNS%')

and snap_id in (select snap_id from (

select se.snap_id, se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and en.name = 'log file sync'

order by avg_time_waited desc)

where rownum < 4)

order by 1,3 desc,2,4;

PROMPT

PROMPT ORDERED BY WAIT_TIME_MILLI

PROMPT Note: This query won't work on 10.2 - ORA-942

select eh.snap_id, eh.instance_number inst, en.name, eh.wait_time_milli, eh.wait_count

from wrh$_event_histogram eh, v$event_name en

where eh.event_id = en.event_id and

(en.name in ('log file sync','gcs log flush sync',

'log file parallel write','wait for scn ack',

'log file switch completion','gc cr grant 2-way',

'gc buffer busy','gc current block 2-way')

or en.name like '%LGWR%' or en.name like '%LNS%')

and snap_id in (select snap_id from (

select se.snap_id, se.time_waited_micro/1000 / se.total_waits avg_time_waited

from wrh$_system_event se, v$event_name en

where se.event_id = en.event_id and en.name = 'log file sync'

order by avg_time_waited desc)

where rownum < 4)

order by 1,4,2,3 desc;

PROMPT

PROMPT ASH DETAILS FOR WORST MINUTES:

PROMPT

PROMPT APPROACH: If you cannot determine the problem from the data

PROMPT above, you may need to look at the details of what each session

PROMPT is doing during each 'bad' snap. Most likely you will want to

PROMPT note the times of the high log file sync waits, look at what

PROMPT LGWR is doing at those times, and go from there...

column program format a45 wra

column sample_time format a25 tru

column event format a30 tru

column time_waited format 999999.999

column p1 format a40 tru

column p2 format a40 tru

column p3 format a40 tru

select sample_time, inst_id inst, session_id, program, event, time_waited/1000 TIME_WAITED,

p1text||': '||p1 p1,p2text||': '||p2 p2,p3text||': '||p3 p3

from gv$active_session_history

where to_char(sample_time,'Mondd_hh24mi') in (select

to_char(sample_time,'Mondd_hh24mi')

from gv$active_session_history

where event = 'log file sync'

group by to_char(sample_time,'Mondd_hh24mi'), inst_id

having avg(time_waited)/1000 > &&threshold)

and time_waited > 0.5

order by 1,2,3,4,5;

select to_char(sysdate,'Mondd hh24:mi:ss') TIME from dual;

spool off

PROMPT

PROMPT OUTPUT FILE IS: lfsdiag_&&dbname&×tamp&&suffix

PROMPT

执行后输出结果如下：

[oracle@node3 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Tue Apr 26 01:35:22 2016

Copyright (c) 1982, 2013, Oracle. All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> @/home/oracle/lfsdiag.sql

TIMECOL SPOO

---------- ----

Apr26_0157 .out

OUTPUT

--------------------------------------------------------------------------------

node3_

LFSDIAG DATA FOR node3_Apr26_0157

Note: All timings are in milliseconds (1000 milliseconds = 1 second)

IMPORTANT PARAMETERS RELATING TO LOG FILE SYNC WAITS:

INST_ID NAME VALUE

---------- ---------------------------------------- ----------------------------------------

1 commit_logging

1 commit_point_strength 1

1 commit_wait

1 commit_write

1 log_archive_dest_1 location=/oradata/arch

1 log_archive_local_first TRUE

1 log_archive_max_processes 4

1 log_archive_min_succeed_dest 1

1 log_archive_start FALSE

1 log_archive_trace 0

ASH THRESHOLD...

This will be the threshold in milliseconds for average log file sync

times. This will be used for the next queries to look for the worst

'log file sync' minutes. Any minutes that have an average log file

sync time greater than the threshold will be analyzed further.

THRESHOLD_IN_MS

---------------

.000

ASH WORST MINUTES FOR LOG FILE SYNC WAITS:

APPROACH: These are the minutes where the avg log file sync time

was the highest (in milliseconds).

MINUTE INST_ID EVENT TOTAL_WAIT_TIME WAITS AVG_TIME_WAITED

------------ ---------- ------------------------------ ----------------- ---------- -----------------

Apr25_2300 1 log file sync 417.397 1 417.397

ASH LFS BACKGROUND PROCESS WAITS DURING WORST MINUTES:

APPROACH: What is LGWR doing when 'log file sync' waits

are happening? LMS info may be relevent for broadcast

on commit and LNS data may be relevant for dataguard.

If more details are needed see the ASH DETAILS FOR WORST

MINUTES section at the bottom of the report.

MINUTE INST PROGRAM EVENT TOTAL_WAIT_TIME WAITS AVG_TIME_WAITED

------------ ---- ---------------------------------------- ------------------------------ ----------------- ---------- -----------------

Apr25_2300 1 oracle@node3 (LGWR) log file parallel write 913.163 1 913.163

Apr25_2300 1 oracle@node3 (M000) log file sync 417.397 1 417.397

HISTOGRAM DATA FOR LFS AND OTHER RELATED WAITS:

APPROACH: Look at the wait distribution for log file sync waits

by looking at "wait_time_milli". Look at the high wait times then

see if you can correlate those with other related wait events.

INST_ID EVENT WAIT_TIME_MILLI WAIT_COUNT

---------- ---------------------------------------- --------------- ----------

1 log file sync 1 66

1 log file sync 2 1

1 log file sync 4 8

1 log file sync 8 37

1 log file sync 16 7

1 log file sync 32 0

1 log file sync 64 12

1 log file sync 128 2

1 log file sync 256 2

1 log file sync 512 1

1 log file sync 1024 1

1 log file switch completion 1 0

1 log file switch completion 2 0

1 log file switch completion 4 1

1 log file switch completion 8 0

1 log file switch completion 16 0

1 log file switch completion 32 1

1 log file parallel write 1 2486

1 log file parallel write 2 188

1 log file parallel write 4 73

1 log file parallel write 8 116

1 log file parallel write 16 102

1 log file parallel write 32 44

1 log file parallel write 64 28

1 log file parallel write 128 10

1 log file parallel write 256 7

1 log file parallel write 512 11

1 log file parallel write 1024 5

1 LGWR wait for redo copy 1 25

1 LGWR wait for redo copy 2 0

1 LGWR wait for redo copy 4 0

1 LGWR wait for redo copy 8 1

1 LGWR wait for redo copy 16 8

ORDERED BY WAIT_TIME_MILLI

INST_ID EVENT WAIT_TIME_MILLI WAIT_COUNT

---------- ---------------------------------------- --------------- ----------

1 log file sync 1 66

1 log file switch completion 1 0

1 log file parallel write 1 2486

1 LGWR wait for redo copy 1 25

1 log file sync 2 1

1 log file switch completion 2 0

1 log file parallel write 2 188

1 LGWR wait for redo copy 2 0

1 log file sync 4 8

1 log file switch completion 4 1

1 log file parallel write 4 73

1 LGWR wait for redo copy 4 0

1 log file sync 8 37

1 log file switch completion 8 0

1 log file parallel write 8 116

1 LGWR wait for redo copy 8 1

1 log file sync 16 7

1 log file switch completion 16 0

1 log file parallel write 16 102

1 LGWR wait for redo copy 16 8

1 log file sync 32 0

1 log file switch completion 32 1

1 log file parallel write 32 44

1 log file sync 64 12

1 log file parallel write 64 28

1 log file sync 128 2

1 log file parallel write 128 10

1 log file sync 256 2

1 log file parallel write 256 7

1 log file sync 512 1

1 log file parallel write 512 11

1 log file sync 1024 1

1 log file parallel write 1024 5

REDO WRITE STATS

"redo write time" in centiseconds (100 per second)

11.1: "redo write broadcast ack time" in centiseconds (100 per second)

11.2: "redo write broadcast ack time" in microseconds (1000 per millisecond)

VERSION INST_ID NAME VALUE MILLISECONDS

----------------- ---------- ---------------------------------------- --------------------- -------------------

11.2.0.4.0 1 redo write info find 162

11.2.0.4.0 1 redo write time 1494 14940.000

11.2.0.4.0 1 redo writes 3070

AWR WORST AVG LOG FILE SYNC SNAPS:

APPROACH: These are the AWR snaps where the average 'log file sync'

times were the highest.

SNAP_ID INST BEGIN END NAME TOTAL_WAIT_TIME TOTAL_WAITS AVG_TIME_WAITED

---------- ---- ------------ ------------ ------------- ----------------- ----------- -----------------

293 1 Apr25_1325 Apr25_1400 log file sync 1296.545 7 185.221

AWR REDO WRITE STATS

"redo write time" in centiseconds (100 per second)

11.1: "redo write broadcast ack time" in centiseconds (100 per second)

11.2: "redo write broadcast ack time" in microseconds (1000 per millisecond)

VERSION SNAP_ID INST STAT_NAME VALUE MILLISECONDS

----------------- ---------- ---- ------------------------------ --------------------- -------------------

11.2.0.4.0 56 1 redo writes 148

11.2.0.4.0 56 1 redo write time 704 7040.000

11.2.0.4.0 56 1 redo write info find 19

11.2.0.4.0 57 1 redo writes 455

11.2.0.4.0 57 1 redo write time 1248 12480.000

11.2.0.4.0 57 1 redo write info find 34

11.2.0.4.0 293 1 redo writes 98

11.2.0.4.0 293 1 redo write time 153 1530.000

11.2.0.4.0 293 1 redo write info find 9

AWR LFS AND OTHER RELATED WAITS FOR WORST LFS AWRs:

APPROACH: These are the AWR snaps where the average 'log file sync'

times were the highest. Look at related waits at those times.

SNAP_ID INST NAME TOTAL_WAITS TOTAL_WAIT_TIME AVG_TIME_WAITED

---------- ---- ---------------------------------------- ----------- ----------------- -----------------

56 1 log file sync 18 3667.963 203.776

56 1 log file parallel write 148 7039.040 47.561

56 1 LGWR wait for redo copy 2 .044 .022

57 1 log file sync 30 4068.399 135.613

57 1 log file parallel write 449 12375.569 27.563

57 1 log file switch completion 4 34.045 8.511

57 1 LGWR wait for redo copy 5 10.986 2.197

293 1 log file sync 7 1296.545 185.221

293 1 log file parallel write 98 1529.263 15.605

293 1 LGWR wait for redo copy 2 10.030 5.015

AWR HISTOGRAM DATA FOR LFS AND OTHER RELATED WAITS FOR WORST LFS AWRs:

Note: This query won't work on 10.2 - ORA-942

APPROACH: Look at the wait distribution for log file sync waits

by looking at "wait_time_milli". Look at the high wait times then

see if you can correlate those with other related wait events.

SNAP_ID INST NAME WAIT_TIME_MILLI WAIT_COUNT

---------- ---- ---------------------------------------- --------------- ----------

56 1 log file sync 1 1

56 1 log file sync 4 2

56 1 log file sync 8 2

56 1 log file sync 32 1

56 1 log file sync 64 1

56 1 log file sync 128 5

56 1 log file sync 256 4

56 1 log file sync 512 1

56 1 log file sync 4096 1

56 1 log file parallel write 1 72

56 1 log file parallel write 2 9

56 1 log file parallel write 4 12

56 1 log file parallel write 8 6

56 1 log file parallel write 16 14

56 1 log file parallel write 32 10

56 1 log file parallel write 64 7

56 1 log file parallel write 128 10

56 1 log file parallel write 256 5

56 1 log file parallel write 512 3

56 1 log file parallel write 2048 1

56 1 log file parallel write 4096 1

56 1 LGWR wait for redo copy 1 2

57 1 log file sync 1 1

57 1 log file sync 2 1

57 1 log file sync 4 3

57 1 log file sync 8 3

57 1 log file sync 16 4

57 1 log file sync 32 2

57 1 log file sync 64 4

57 1 log file sync 128 5

57 1 log file sync 256 5

57 1 log file sync 512 1

57 1 log file sync 4096 1

57 1 log file switch completion 2 1

57 1 log file switch completion 4 1

57 1 log file switch completion 8 1

57 1 log file switch completion 32 1

57 1 log file parallel write 1 163

57 1 log file parallel write 2 37

57 1 log file parallel write 4 39

57 1 log file parallel write 8 44

57 1 log file parallel write 16 51

57 1 log file parallel write 32 51

57 1 log file parallel write 64 36

57 1 log file parallel write 128 19

57 1 log file parallel write 256 9

57 1 log file parallel write 512 3

57 1 log file parallel write 1024 1

57 1 log file parallel write 2048 1

57 1 log file parallel write 4096 1

57 1 LGWR wait for redo copy 1 4

57 1 LGWR wait for redo copy 16 1

293 1 log file sync 1 5

293 1 log file sync 8 1

293 1 log file sync 2048 1

293 1 log file parallel write 1 86

293 1 log file parallel write 2 1

293 1 log file parallel write 4 2

293 1 log file parallel write 8 2

293 1 log file parallel write 16 3

293 1 log file parallel write 32 3

293 1 log file parallel write 2048 1

293 1 LGWR wait for redo copy 1 1

293 1 LGWR wait for redo copy 16 1

ORDERED BY WAIT_TIME_MILLI

Note: This query won't work on 10.2 - ORA-942

SNAP_ID INST NAME WAIT_TIME_MILLI WAIT_COUNT

---------- ---- ---------------------------------------- --------------- ----------

56 1 log file sync 1 1

56 1 log file parallel write 1 72

56 1 LGWR wait for redo copy 1 2

56 1 log file parallel write 2 9

56 1 log file sync 4 2

56 1 log file parallel write 4 12

56 1 log file sync 8 2

56 1 log file parallel write 8 6

56 1 log file parallel write 16 14

56 1 log file sync 32 1

56 1 log file parallel write 32 10

56 1 log file sync 64 1

56 1 log file parallel write 64 7

56 1 log file sync 128 5

56 1 log file parallel write 128 10

56 1 log file sync 256 4

56 1 log file parallel write 256 5

56 1 log file sync 512 1

56 1 log file parallel write 512 3

56 1 log file parallel write 2048 1

56 1 log file sync 4096 1

56 1 log file parallel write 4096 1

57 1 log file sync 1 1

57 1 log file parallel write 1 163

57 1 LGWR wait for redo copy 1 4

57 1 log file sync 2 1

57 1 log file switch completion 2 1

57 1 log file parallel write 2 37

57 1 log file sync 4 3

57 1 log file switch completion 4 1

57 1 log file parallel write 4 39

57 1 log file sync 8 3

57 1 log file switch completion 8 1

57 1 log file parallel write 8 44

57 1 log file sync 16 4

57 1 log file parallel write 16 51

57 1 LGWR wait for redo copy 16 1

57 1 log file sync 32 2

57 1 log file switch completion 32 1

57 1 log file parallel write 32 51

57 1 log file sync 64 4

57 1 log file parallel write 64 36

57 1 log file sync 128 5

57 1 log file parallel write 128 19

57 1 log file sync 256 5

57 1 log file parallel write 256 9

57 1 log file sync 512 1

57 1 log file parallel write 512 3

57 1 log file parallel write 1024 1

57 1 log file parallel write 2048 1

57 1 log file sync 4096 1

57 1 log file parallel write 4096 1

293 1 log file sync 1 5

293 1 log file parallel write 1 86

293 1 LGWR wait for redo copy 1 1

293 1 log file parallel write 2 1

293 1 log file parallel write 4 2

293 1 log file sync 8 1

293 1 log file parallel write 8 2

293 1 log file parallel write 16 3

293 1 LGWR wait for redo copy 16 1

293 1 log file parallel write 32 3

293 1 log file sync 2048 1

293 1 log file parallel write 2048 1

ASH DETAILS FOR WORST MINUTES:

APPROACH: If you cannot determine the problem from the data

above, you may need to look at the details of what each session

is doing during each 'bad' snap. Most likely you will want to

note the times of the high log file sync waits, look at what

LGWR is doing at those times, and go from there...

SAMPLE_TIME INST SESSION_ID PROGRAM EVENT TIME_WAITED

------------------------- ---- ---------- --------------------------------------------- ------------------------------ -----------

P1 P2 P3

---------------------------------------- ---------------------------------------- ----------------------------------------

25-APR-16 11.00.45.557 PM 1 11 oracle@node3 (LGWR) log file parallel write
913.163

files: 1 blocks: 184 requests: 1

25-APR-16 11.00.45.557 PM 1 40
oracle@node3 (M000) log file sync 417.397

buffer#: 1853 sync scn: 913952899 : 0

TIME

--------------

Apr26 01:57:24

OUTPUT FILE IS: lfsdiag_node3_Apr26_0157.out