{"id":413,"date":"2015-08-24T05:32:51","date_gmt":"2015-08-24T05:32:51","guid":{"rendered":"http:\/\/haisins.epac.to\/wordpress\/?p=413"},"modified":"2015-08-24T05:32:51","modified_gmt":"2015-08-24T05:32:51","slug":"oracle-latch-%eb%9e%80","status":"publish","type":"post","link":"http:\/\/haisins.synology.me\/wordpress\/?p=413","title":{"rendered":"Oracle Latch \ub780??"},"content":{"rendered":"

\uc624\ub77c\ud074\uc5d0\uc11c Latch\ub294 Lock\uacfc \ud568\uaed8 \uc7a0\uae08\uc5d0 \uc0ac\uc6a9\ub418\ub294 \uc7a5\uce58\uc774\ub2e4. \uadf8\ub7ec\ub098 Lock\uacfc \ud2c0\ub9b0\uac83\uc740 latch\ub294 Lock\ubcf4\ub2e4 \uac00\ubccd\uace0 SGA \ub0b4\ubd80\uc758 \uacf5\uc720 \ub370\uc774\ud130\uc5d0 \ub300\ud55c \ubca0\ud0c0\uc801\uc778 \uc7a0\uae08\uc744 \ubcf4\uc7a5\ud558\uc5ec (9i \uc774\uc0c1\uc5d0\uc11c\ub294 cache buffer chains Latch\ub294 \uc77d\uae30 \uc804\uc6a9\uc77c \uacbd\uc6b0 Shared \ubaa8\ub4dc \uac00\ub2a5), \uba54\ubaa8\ub9ac \uad6c\uc870\uc758 \ubb34\uacb0\uc131\uc744 \uc720\uc9c0\ud558\ub3c4\ub85d \ud558\ub294\uac83\uc774 \ubaa9\uc801\uc774\ub2e4. \ub530\ub77c\uc11c \ud55c \uc21c\uac04\uc5d0 \ud558\ub098\uc758 \ud504\ub85c\uc138\uc2a4\ub9cc\uc774 latch\ub97c \ubcf4\uc720\ud560 \uc218 \uc788\ub2e4\ub294 \uc18c\ub9ac\uc774\ub2e4 . \ub610 , SGA\uc5d0 \uc811\uadfc\ud558\ub294 \ubaa8\ub4e0 \ud504\ub85c\uc138\uc2a4\ub294 \ubc18\ub4dc\uc2dc \ud574\ub2f9 \uc601\uc5ed\uc744 \uad00\uc7a5\ud558\ub294 Latch\ub97c \ud68d\ub4dd\ud574\uc57c\uc9c0\ub9cc \uc811\uadfc\uc774 \uac00\ub2a5\ud558\ub2e4.<\/span><\/p>\n

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Latch\ub294 PID , Memory Address , Length\ub85c \uad6c\uc131\ub41c \uba54\ubaa8\ub9ac \uac1d\uccb4\uc774\ub2e4.<\/span><\/p>\n

\ub610 Latch\ub294 \ubb3c\ub9ac\uc801\uc73c\ub85c Shared Pool\uc548\uc5d0 \uc874\uc7ac\ud558\ub294 \uba54\ubaa8\ub9ac \uad6c\uc870\uccb4 \uc774\ub2e4. Latch\ub294 \ub9e4\uc6b0 \uac04\ub2e8\ud558\uace0 \uc791\uc740 \uba54\ubaa8\ub9ac \uc601\uc5ed\uc744 \uc0ac\uc6a9\ud55c\ub2e4.<\/span><\/p>\n

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Latch\uc5d0\ub294 Parent , Child , Solitary\uc758 \uc138\uac00\uc9c0 \uc720\ud615\uc774 \uc788\ub2e4. Parent\uc640 Solitary Latch\ub294 \uc624\ub77c\ud074\uc758 \ucee4\ub110 \ucf54\ub4dc \uc548\uc5d0 \uc815\uc758 \ub418\uc5b4 \uc788\uace0 ,Child \ub798\uce58\ub294 \uc778\uc2a4\ud134\uc2a4\uac00 \uad6c\ub3d9\ub420 \ub54c \uc0dd\uc131\uc774 \ub41c\ub2e4.<\/span><\/p>\n

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v$latch_parent , v$latch_children\ubdf0\ub294 Parent , Child Latch\uc5d0 \ub300\ud55c \ud1b5\uacc4\uc815\ubcf4\uac00 \uc800\uc7a5\ub41c\ub2e4.<\/span><\/p>\n

v$latch\ub294 \uc138 \uac00\uc9c0 \uc720\ud615\uc758 latch \ud1b5\uacc4\uc815\ubcf4\ub97c \ud655\uc778 \ud560 \uc218 \uc788\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

Latch\ub294 Lock\uacfc \ub2e4\ub978 \uc810\uc774 Deadlock\uc774 \uc874\uc7ac\ub97c \ud558\uc9c0 \uc54a\ub294\ub2e4\ub294 \uac83\uc774\ub2e4. \uc774\uac83\uc740 latch\uc758 \ub3d9\uc791 \uba54\uce74\ub2c8\uc998\uc744 \ud655\uc778\ud574 \ubcf4\uba74 \uc54c \uc218 \uc788\ub294\ub370 <\/span><\/p>\n

\uac00\ub839 \ud558\ub098\uc758 Latch\ub97c \ubcf4\uc720\ud55c Process\uac00 \ub2e4\ub978 latch\ub97c \ud68d\ub4dd\ud558\uace0\uc790 \ud55c\ub2e4\uba74 \ubc18\ub4dc\uc2dc \ud604\uc7ac \ubcf4\uc720\ud55c Latch \ubcf4\ub2e4 \ub192\uc740 level\uc758 Latch\ub9cc\uc744 \ud68d\ub4dd\ud574\uc57c \ud55c\ub2e4.<\/span><\/p>\n

\uc608\ub97c \ub4e4\uc5b4\ubcf4\uba74 3\uc774\ub77c\ub294 Latch\ub97c \ubcf4\uc720\ud55c Process\uac00 1 \uc774\ub77c\ub294 latch\ub97c \ucd94\uac00\uc801\uc73c\ub85c \ud68d\ub4dd\ud574\uc57c \ud55c\ub2e4\uba74 Deadlock\uc744 \ubc29\uc9c0 \ud558\uae30 \uc704\ud558\uc5ec no-wait \ubaa8\ub4dc\ub85c \ud68d\ub4dd\uc744 \uc2dc\ub3c4\ud574\uc57c \ud55c\ub2e4. \ub9cc\uc57d no-wait\ubaa8\ub4dc\ub85c \ud68d\ub4dd \uc694\uccad\uc2dc \uc2e4\ud328\ub97c \ud55c\ub2e4\uba74 \uae30\uc874\uc5d0 \ud68d\ub4dd\ud558\uace0 \uc788\ub358 3 \uc774\ub77c\ub294 latch\ub97c \ub193\uace0 1 \uc774\ub77c\ub294 Latch\ub97c \ud68d\ub4dd \ud6c4 3 \uc774\ub77c\ub294 latch\ub97c \uc2dc\ub3c4\ud574\uc57c \ud55c\ub2e4.<\/span><\/p>\n

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Latch\ub97c \ud68d\ub4dd\ud558\ub824\ub294 \ud504\ub85c\uc138\uc2a4\ub4e4\uc740 Latch\ub97c \ud68d\ub4dd \ud558\uae30 \uc804\uae4c\uc9c0\ub294 \uacc4\uc18d\ud574\uc11c \ud68d\ub4dd\ud558\uae30 \uc704\ud558\uc5ec \uc2dc\ub3c4\ub97c \ud558\uac8c \ub418\ub294\ub370 \uc774 \ud68d\ub4dd \ud558\ub294 \ubc29\ubc95\uc5d0 \ub530\ub77c\uc11c<\/span><\/p>\n

no-wait \ubaa8\ub4dc\uc640 willing-to-wait \ubaa8\ub4dc\uac00 \uc874\uc7ac \ud55c\ub2e4.<\/span><\/p>\n

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no-wait \ubaa8\ub4dc\ub85c \ud68d\ub4dd\uc744 \uc2dc\ub3c4\ud558\ub294 \ud504\ub85c\uc138\uc2a4\ub4e4\uc5d0 \ub300\ud55c \ud1b5\uacc4\uc815\ubcf4\ub294 v$latch , v$latch_parent , v$latch_children\uacfc \uac19\uc740 \ub808\uce58 \uad00\ub828 \ubdf0\uc758 Immediate_gets\uc640 immediate_misses \uceec\ub7fc\uac12\uc744 \ubcf4\uba74 \uc54c \uc218 \uc788\ub2e4. no-wait\ubaa8\ub4dc\ub294 \ud604\uc7ac \uc790\uc2e0\uc774 \uac00\uc9c4 latch\ubcf4\ub2e4 \ub0ae\uc740 level\uc758 latch\ub97c \uc694\uad6c \ud560 \uc2dc\uc5d0 Deadlock\ubc1c\uc0dd\uc744 \ubc29\uc9c0 \ud558\uae30 \uc704\ud558\uc5ec \ud68d\ub4dd \uc2dc\ub3c4 \ud6c4 \uc2e4\ud328 \ud558\uba74 \ub354 \uc774\uc0c1 \ud68d\ub4dd \uc2dc\ub3c4\ub97c \ud558\uc9c0 \uc54a\ub294 \ub2e4\ub294 \ub73b\uc774\ub2e4. \uc880 \ub354 \uc815\ud655\ud788 \ub9d0\ud558\uc790\uba74 \ud604\uc7ac \uac00\uc9c0\uace0 \uc788\ub294 latch\uc758 level\ubcf4\ub2e4 \ub0ae\uc740 level\uc758 Latch\ub97c \ud68d\ub4dd\ud558\ub824\uace0 \ud560 \uacbd\uc6b0 \ub0ae\uc740 level\uc758 latch \ubcf4\ub2e4 \ud070 latch\ub294 \ubaa8\ub450 \ud574\uc81c \ud558\uace0 \ub0ae\uc740 level\uc758 latch \ubd80\ud130 \ub2e4\uc2dc \ud68d\ub4dd\uc744 \uc2dc\ub3c4 \ud574\uc57c \ud55c\ub2e4.<\/span><\/p>\n

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willing-to-wait \ubaa8\ub4dc\ub85c \ud68d\ub4dd\ub41c Latch \uc815\ubcf4\ub294 Gets \uc640 Misses \uceec\ub7fc\uc5d0 \ud1b5\uacc4\uc815\ubcf4\ub97c \uc800\uc7a5\ud55c\ub2e4. \uc77c\ubc18\uc801\uc778 latch\ub4e4\uc774 \ubaa8\ub450 willing-to-wait \ubaa8\ub4dc\ub97c \uc0ac\uc6a9\ud55c\ub2e4. gets\ub294  willing-to-wait \ubaa8\ub4dc\ub85c latch\ub97c \uc694\uccad\ud560\ub54c \uc99d\uac00\ud55c\ub2e4. \ud68d\ub4dd \uc2e4\ud328\uc2dc misses \ubc0f spin_gets\uac12\uc774 1 \uc529 \uc99d\uac00 \ud55c\ub2e4.<\/span><\/p>\n

willing-to_wait \ubaa8\ub4dc\uc5d0\uc11c \uc0ac\uc6a9\ub418\ub294 \ubc29\ubc95\uc73c\ub85c \ub450\uac00\uc9c0\uac00 \uc788\ub294\ub370 \ud558\ub098\ub294 Spin \ubaa8\ub4dc\uc774\uace0 \ub2e4\ub978 \ud558\ub098\ub294 posting \ubaa8\ub4dc \uc774\ub2e4.<\/span><\/p>\n

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spin \ubaa8\ub4dc\ub294 latch\ub97c \ud68d\ub4dd\ud560 \uc218 \uc788\ub294 \uc2dc\uac04\uc774 \ube44\uad50\uc801 \uc9e7\uc73c\ub9ac\ub77c\ub294 \uae30\ub300 \uc18d\uc5d0 \ucc98\uc74c latch \ud68d\ub4dd \uc2dc\ub3c4 \ud6c4 \uc2e4\ud328 \ud558\uba74 \uc9e7\uc740 \uc2dc\uac04 sleep-wake\ub97c \ubc18\ubcf5\ud558\uba74\uc11c Latch\ub97c \ud68d\ub4dd \ud558\ub824\uace0 \uc2dc\ub3c4\ub97c \ud558\ub294 \uac83\uc774\ub2e4. \uc774 \ubc18\ubcf5 \ud69f\uc218\ub294 _spin_count \ud69f\uc218 \uc774\uba70 \uae30\ubcf8\uac12\uc740 2000\ubc88\uc774\ub2e4.<\/span><\/p>\n

\uc77c\ubc18\uc801\uc73c\ub85c \uc774 \ubaa8\ub4dc\ub85c Latch \ud68d\ub4dd\uc744 \uc2dc\ub3c4 \ud558\ub294 \uac83\uc774 \uc77c\ubc18\uc801\uc774\ub2e4. sleep\ud588\ub2e4\uac00 wake \ud558\ub294 \uc2dc\uac04 \uc8fc\uae30\ub3c4 \ub9e4\ubc88 \uac19\uc740 \uac83\uc774 \uc544\ub2c8\ub77c \uc5b4\ucc28\ud53c sleep-wake\ud558\ub294 \ubd80\ubd84\uc5d0 CPU\ub97c \uc0ac\uc6a9\ud558\uac8c \ub418\ubbc0\ub85c Latch \ud68d\ub4dd \uc2dc \uc0ac\uc6a9\ud558\ub294 cpu \uc790\uc6d0 \uc18c\ubaa8\ub97c \uc904\uc774\uae30 \uc704\ud558\uc5ec sleep-wake \ud69f\uc218\uac00 \uc99d\uac00 \ud560 \uc218\ub85d sleep \uc2dc\uac04\uc774 \uc99d\uac00\ub97c \ud55c\ub2e4. \uc774 \uc2dc\uac04\uc740 \ucd5c\ub300 2\ucd08 \uae4c\uc9c0 \uc99d\uac00\ub97c \ud55c\ub2e4. \ucc38\uace0\ub85c cpu\uac00 1\uac1c\uc778 \uc2dc\uc2a4\ud15c\uc5d0\uc11c\ub294 spin\uc744 \uc218\ud589\ud558\uc9c0 \uc54a\ub294\ub2e4. \ub530\ub77c\uc11c \ud655\uc778\ud574 \ubcf4\uba74 _spin_count\ub3c4 1\uac12\uc744 \ub098\ud0c0\ub0b8\ub2e4.<\/span><\/p>\n

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posting \ubaa8\ub4dc\ub294 spin \ubaa8\ub4dc\uc640\ub294 \ub2e4\ub974\uac8c latch \ud68d\ub4dd \uc2e4\ud328 \ud6c4 Latch wait list\uc5d0 \uc790\uc2e0\uc744 \ub4f1\ub85d\ud574 \ub193\uc740 \ud6c4 \uae30\uc874\uc5d0 latch\ub97c \ud68d\ub4dd \ud558\uace0 \uc788\ub358 Process\uac00 \uc791\uc5c5\uc774 \ub05d\ub09c \ud6c4 \uae68\uc6cc(post)\uc8fc\uae30\ub97c \ubc14\ub77c\ub294 \ubaa8\ub4dc\uc774\ub2e4. latch wait list\uc5d0 \ub4f1\ub85d\uc774 \ub418\uc5b4 \uc788\ub2e4\uace0 \ub4f1\ub85d \uc21c\uc11c\ub300\ub85c latch\ub97c \ud68d\ub4dd \ud560 \uc218 \uc788\ub294 \uac83\uc774 \uc544\ub2c8\ub77c \uadf8 \uc21c\uac04 \uc2dc\ub3c4\ud558\ub294 process\ub4e4 \ub07c\ub9ac \ub2e4\uc2dc \uacbd\ud569\uc744 \ud558\uac8c \ub41c\ub2e4. \uc774 \ubaa8\ub4dc\ub97c \uc0ac\uc6a9\ud558\ub294 \uac83\uc740 \ube44\uad50\uc801 latch \uc0ac\uc6a9 \uae30\uac04\uc774 \uae34 shared pool , library cache latch\ub4e4\uc774 \uc774 \ubaa8\ub4dc\ub97c \uc0ac\uc6a9\ud55c\ub2e4.<\/span><\/p>\n

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\ub9cc\uc57d latch\ub97c \ud68d\ub4dd\ud558\uace0 \uc788\ub358 process\uac00 \ube44 \uc815\uc0c1 \uc885\ub8cc \ub41c \uacbd\uc6b0 latch \ud68d\ub4dd\uc740 \uc5b4\ub5bb\uac8c \ub418\ub294\uac00 ? \ubb34\ud55c\uc815 \uae30\ub2e4\ub9ac\uac70\ub098 \uacc4\uc18d\ud574\uc11c spin\uc744 \uc218\ud589\ud558\ub294\uac00 ?<\/span><\/p>\n

\uc774\ub7f0 \ubd80\ubd84\ub54c\ubb38\uc5d0 latch cleanup \uba54\uce74\ub2c8\uc998\uc774 \ud544\uc694\ud55c\ub370 \uc774\ub294 latch\ub97c \ud68d\ub4dd \ud6c4 \uc790\uc2e0\uc774 \ubcc0\uacbd\ud558\uace0\uc790 \ud558\ub294 \ubd80\ubd84\uacfc \ubaa9\uc801\uc744 latch recovery area\uc5d0 \ub4f1\ub85d\uc744 \ud574 \ub193\ub294\ub2e4. \uadf8\ub798\uc11c process \ube44\uc815\uc0c1 \uc885\ub8cc \ub2f4\ub2f9 pmon\uc774 \ud574\ub2f9 \ube44\uc815\uc0c1 \ud504\ub85c\uc138\uc2a4\uac00 \uc0ac\uc6a9\ud558\ub358 latch\uc5d0 \ub300\ud574\uc11c cleanup function\uc744 \ud638\ucd9c\ud558\uc5ec latch\ub97c \ud574\uc81c \ud55c\ub2e4. latch \uc2dc\ub3c4\ub97c 4\ubc88\uc774\uc0c1 \uc2dc\ub3c4\ud55c process\ub294 pmon\uc5d0\uac8c \ud574\ub2f9 latch\ub97c \ubcf4\uc720\ud55c process\uac00 \uc0b4\uc544 \uc788\ub294\uc9c0\uc5d0 \ub300\ud55c \uccb4\ud06c \uc694\uccad\uc744 \uc2dc\ub3c4 \ud55c\ub2e4.  <\/span><\/p>\n

 <\/span><\/p>\n

Latch \ud68d\ub4dd \ub8e8\ud2f4\uc740 \ubc18\ub4dc\uc2dc Latch\ub97c \ud68d\ub4dd \ud558\uc5ec\uc57c\ub9cc \uc885\ub8cc\uac00 \ub41c\ub2e4. \uadf8\ub798\uc11c Latch Free Event\ub4e4\uc774 \ubc1c\uc0dd\uc744 \ud558\ub294 \uac83\uc774\uace0 \uc774\ub85c \uc778\ud558\uc5ec \uc131\ub2a5 \uc774\uc288\uac00 \ubc1c\uc0dd\uc774 \ub418\ub294 \uac83\uc774\ub2e4.<\/span><\/p>\n

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Latch \uad00\ub828 \uc131\ub2a5 \ubdf0\ub294 \ub2e4\uc74c\uacfc \uac19\uc774 \uba87\uac1c\uac00 \uc874\uc7ac \ud558\ub294\ub370 \uc790\uc138\ud55c \uac83\uc740 Oracle Document\ub97c \ucc38\uc870 ..<\/span><\/p>\n

 <\/span><\/p>\n

v$latch \/ v$latch_parent \/ v$latch_children \/ v$latchholder \/ v$latch_missed<\/span><\/p>\n

 <\/span><\/p>\n

\uc0ac\uc6a9\ub418\ub294 Children Latch \uc885\ub958 \ubc0f \uac1c\uc218\ub97c \ud655\uc778 \ud558\ub824\uba74 \ub2e4\uc74c \ucffc\ub9ac\ub97c \uc0ac\uc6a9\ud558\uba74 \ub41c\ub2e4.<\/span><\/p>\n

\ub2e4\uc74c\uc758 \ucffc\ub9ac \uc608\ub294 Oracle 10g R2 \uc5d0\uc11c \uc218\ud589\ud574\ubcf8 \uacb0\uacfc \uc774\ub2e4.<\/span><\/p>\n

 <\/p>\n

SQL>SELECT name , count(*) FROM v$latch_children GROUP BY name<\/p>\n

NAME                                                        COUNT(*)
———————————– ——————–
enqueue hash chains                                          2
channel operations parent latch                         88
name-service namespace bucket                        32
cache buffers chains<\/font>                                     1024
redo copy                                                         4
redo allocation                                                 20
intra txn parallel recovery                                 40
library cache pin                                                3
resmgr:session queuing                                       1
longop free list parent                                        2
session queue latch                                            1
sim partition latch                                              1
commit callback allocation                                 11
Shared B-Tree                                                  3
virtual circuit queues                                        6
job workq parent latch                                      3
JS queue access latch                                      13
session idle bit                                                 2
ksfv messages                                                  2
checkpoint queue latch                                    16
object queue header operation                          8
flashback copy                                                  6
undo global data                                               3
library cache lock allocation                               3
SQL memory manager workarea list latch           67
JS slv state obj latch                                         4
client\/application info                                        2
OS process                                                      22
row cache objects                                           34
shared pool<\/font>                                                      7
library cache hash chains                                  3
resmgr:actses change state                            150
resmgr:plan CPU method                                    2
shared pool sim alloc                                       17
post\/wait queue                                               5
done queue latch                                              1
channel handle pool latch                                  1
granule operation                                            1
buffer pool<\/font>                                                     8
simulator hash latch                                      32
transaction allocation                                    11
library cache lock<\/font>                                            3
shared pool simulator                                    17
peplm                                                            3
session switching                                           4
msg queue latch                                             1
message pool operations parent latch             38
slave class                                                    6
msg queue                                                   18
simulator lru latch                                         8
global tx hash mapping                                 47
parallel query stats                                       2
business card                                               8
logminer context allocation                            1
In memory undo latch                                   18 
library cache  <\/font>                                              3
library cache pin allocation                            3
resmgr:actses change group                        150
parallel query alloc buffer                               4
cache buffers lru chain<\/font>                                    8
object queue header heap                                8
kks stats                                                         4
resmgr:resource group CPU method                    1
JS Sh mem access                                            2<\/p>\n

64 rows<\/p>\n

 <\/p>\n

\uc704\uc758 Latch \uac1c\uc218\ub4e4\uc740 SGA \ud06c\uae30 \ubc0f \uae30\ud0c0 CPU \uac1c\uc218 \ub4f1 \ub4f1 \uac01\uac01\uc758 Oracle Server \ud658\uacbd\ub9c8\ub2e4 \ucc28\uc774\uac00 \uc788\uc744 \uc218 \uc788\ub2e4.<\/span><\/p>\n

\ub2e8\uc9c0 , \uc5b4\ub5a4 \uac83\ub4e4\uc774 \uc788\ub294\uc9c0 \ud655\uc778\ud574 \ubcf4\uae30 \uc704\ud574\uc11c \ucffc\ub9ac\ub97c \uc218\ud589\ud574 \ubcf4\uae38 \uad8c\ud55c\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

\uc2e4\uc81c \uc6b4\uc601\ud558\uba74\uc11c \ub9ce\uc774 \ubcf4\uc558\uc744 \ub9cc\ud55c Latch \uc774\ub984\ub4e4\uc774 \ubcf4\uc774\ub9ac\ub77c \uc0dd\uac01\uc774 \ub41c\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

\uadf8\ub7fc \uc5ec\uae30\uc11c \uac01\uac01\uc758 Latch \ubcc4 Event \uc124\uba85\uc744 \ud558\uae30 \uc804\uc5d0 \uac04\ub2e8\ud788 Latch Free Event\uac00 \ub098\ud0c0\ub0b4\ub294 \ud56d\ubaa9\uc744 \ud655\uc778\ud574 \ubcf4\uba74<\/span><\/p>\n

 <\/span><\/p>\n

v$session_wait \ubdf0\uc5d0\uc11c latch Free Event\uac00 \ub098\ud0c0\ub09c\ub2e4\ub294 \uac83\uc740 \ud504\ub85c\uc138\uc2a4\uac00 willing-to_wait \ubaa8\ub4dc\ub85c _spin_count\uc5d0 \uc9c0\uc815\ub41c \uc218\uce58\ub9cc\ud07c<\/span><\/p>\n

\ubc18\ubcf5\ud574\uc11c \ub798\uce58\ub97c \ud68d\ub4dd \ud558\ub824\uace0 \uc2dc\ub3c4\ub97c \ud558\uace0 \uc788\uc73c\ub098 \ud68d\ub4dd\uc744 \ubabb\ud558\uace0 sleep \uc0c1\ud0dc\ub85c \ub418\uc5b4 \uc788\ub2e4\ub294 \ub73b\uc774\ub2e4.<\/span><\/p>\n

SPIN\uc740 CPU job \uc774\ubbc0\ub85c \uc5ec\ub7ec \ud504\ub85c\uc138\uc2a4\uc5d0\uc11c \ub3d9\uc2dc\uc5d0 \uac19\uc740 Latch\uc5d0 \ub300\ud55c \uacbd\ud569\uc744 \uc77c\uc73c\ud0a4\uba74 latch\ub97c \ud68d\ub4dd\ud558\uc9c0 \ubabb\ud55c \ud504\ub85c\uc138\uc2a4\ub4e4\uc740 Spin\uc744 \uc2dc\ub3c4 \ud558\uae30<\/span><\/p>\n

\ub54c\ubb38\uc5d0 \uadf8\ub9cc \ud07c CPU \uc0ac\uc6a9\ub960\uc774 \ub192\uc544 \uc9c4\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

Latch Free Event\ub294 P1 , P2 , P3 \uc778\uc790\ub97c \uac00\uc9c0\uace0 \ub098\ud0c0\ub098\ub294\ub370  \uac01\uac01\uc758 \ub73b\uc740 \uc544\ub798\uc640 \uac19\ub2e4.<\/span><\/p>\n

 – P1 : Latch Address<\/span><\/p>\n

 – P2 : Latch Number<\/span><\/p>\n

 – P3 : the Number of Tries<\/span><\/p>\n

 <\/span><\/p>\n

Latch Free Event\uac00 \ubc1c\uc0dd\ud558\uace0 \uc788\uc744 \ub2f9\uc2dc\uc5d0 P1RAW \uac12\uc744 \uac00\uc9c0\uace0 v$latch_children \ubdf0\uc758 addr\uacfc \ube44\uad50\ub97c \ud574\ubcf4\uba74 \uc5b4\ub5a4 Latch\ub97c \ud68d\ub4dd\ud558\uae30 \uc704\ud574\uc11c<\/span><\/p>\n

\ub300\uae30\ub97c \ud558\uace0 \uc788\ub294\uc9c0 \ud655\uc778\uc774 \uac00\ub2a5\ud558\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

P1\uac12\uc740 Address\uc5d0 \ub300\ud55c \uc2ed\uc9c4\uc218 \uc774\uace0 P1RAW\uac12\uc740 Address\uc5d0 \ub300\ud55c Hex\uac12\uc774\ub2e4<\/span><\/p>\n

\uc608\ub97c \ub4e4\uc5b4 P1\uac12\uc774 536975932 \uc774\uace0 P1RAW\uac12\uc774 0000000020019A3C \uc774\uba74 P1RAW\uac12\uc5d0\uc11c \uc55e\uc5d0 0 \uc744 \ube7c\uace0 \ub123\uc5b4\uc11c \uc870\ud68c \ud558\uba74 \ub41c\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

SELECT NAME , IMMEDIATE_GETS , IMMEDIATE_MISSES , GETS , MISSES , SPIN_GETS , SLEEPS<\/span>
FROM   v$latch_children<\/span>
WHERE addr = ‘P1 RAW’ ;<\/span><\/p>\n

 <\/span><\/p>\n

 <\/span><\/p>\n

\ud604\uc7ac Latch Holder\uc5d0 \ub300\ud55c \uc815\ubcf4 \ud655\uc778 \ucffc\ub9ac \uc785\ub2c8\ub2e4.<\/span><\/p>\n

 <\/span><\/p>\n

Latch holder\uc758 \uc138\uc158 \uc815\ubcf4 \ubc0f \uc218\ud589\ud558\ub294 \ucffc\ub9ac \ud655\uc778<\/span><\/p>\n

 <\/span><\/p>\n

SELECT \/*+ ORDERED *\/<\/span>
       h.laddr AS latchaddress ,<\/span>
       h.name ,<\/span>
       s.username ,<\/span>
       s.schemaname ,<\/span>
       s.program ,<\/span>
       s.sql_hash_value ,<\/span>
       t.hash_value ,<\/span>
       t.piece ,<\/span>
       t.sql_text<\/span>
FROM   v$latchholder h ,<\/span>
       v$session s ,<\/span>
       v$sqltext t<\/span>
WHERE  h.sid = s.sid<\/span>
AND    s.sql_address = t.address( + ) ;<\/span><\/p>\n

 <\/span><\/p>\n

SQL\ubb38\uc774 \uc788\uc744 \uc218\ub3c4 \uc5c6\uc744 \uc218\ub3c4 \uc788\uc73c\ubbc0\ub85c Outer \uc870\uc778\uc73c\ub85c \ud574 \uc90c<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

\uc624\ub77c\ud074\uc5d0\uc11c Latch\ub294 Lock\uacfc \ud568\uaed8 \uc7a0\uae08\uc5d0 \uc0ac\uc6a9\ub418\ub294 \uc7a5\uce58\uc774\ub2e4. \uadf8\ub7ec\ub098 Lock\uacfc \ud2c0\ub9b0\uac83\uc740 latch\ub294 Lock\ubcf4\ub2e4 \uac00\ubccd\uace0 SGA \ub0b4\ubd80\uc758 \uacf5\uc720 \ub370\uc774\ud130\uc5d0 \ub300\ud55c \ubca0\ud0c0\uc801\uc778 \uc7a0\uae08\uc744 \ubcf4\uc7a5\ud558\uc5ec (9i \uc774\uc0c1\uc5d0\uc11c\ub294 cache buffer chains Latch\ub294 \uc77d\uae30 \uc804\uc6a9\uc77c \uacbd\uc6b0 Shared \ubaa8\ub4dc \uac00\ub2a5), \uba54\ubaa8\ub9ac \uad6c\uc870\uc758 \ubb34\uacb0\uc131\uc744 \uc720\uc9c0\ud558\ub3c4\ub85d \ud558\ub294\uac83\uc774 \ubaa9\uc801\uc774\ub2e4. \ub530\ub77c\uc11c \ud55c \uc21c\uac04\uc5d0 \ud558\ub098\uc758 \ud504\ub85c\uc138\uc2a4\ub9cc\uc774 latch\ub97c \ubcf4\uc720\ud560 \uc218 \uc788\ub2e4\ub294 \uc18c\ub9ac\uc774\ub2e4 . \ub610 , SGA\uc5d0 \uc811\uadfc\ud558\ub294 \ubaa8\ub4e0 \ud504\ub85c\uc138\uc2a4\ub294 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"spay_email":""},"categories":[11],"tags":[148,149,150,151],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/413"}],"collection":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=413"}],"version-history":[{"count":0,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/413\/revisions"}],"wp:attachment":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=413"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=413"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}