Scripts:查询log file sync 等待的脚本lfsdiag.sql

-- 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