{"id":2630,"date":"2018-02-02T16:07:28","date_gmt":"2018-02-02T07:07:28","guid":{"rendered":"http:\/\/haisins.epac.to\/wordpress\/?p=2630"},"modified":"2018-02-02T16:08:47","modified_gmt":"2018-02-02T07:08:47","slug":"redo-log-file-%ec%82%ac%ec%9d%b4%ec%a6%88","status":"publish","type":"post","link":"https:\/\/haisins.synology.me\/wordpress\/?p=2630","title":{"rendered":"REDO LOG FILE \uc0ac\uc774\uc988"},"content":{"rendered":"<p>\ubcf4\ud1b5\uc758 \uc0ac\uc774\ud2b8\uc5d0\uc11c Redo log \ud06c\uae30\uc5d0 \ub300\ud574 \uc5b8\uae09\ud560 \ub54c\ub9c8\ub2e4 \ub108\ubb34 \ucee4\uc9c0\uba74 \uc131\ub2a5 \uc800\ud558\uac00 \uc77c\uc5b4\ub098\uc9c0 \uc54a\uc744\uae4c \uc6b0\ub824\ud558\ub294 \uacbd\uc6b0\ub97c \uc790\uc8fc \uc811\ud558\uac8c \ub429\ub2c8\ub2e4.<\/p>\n<p>\uadf8\ub7f0\ub370 \uc0ac\uc2e4 Redo \ub85c\uadf8\ub294 \ucee4\uc9c8\uc218\ub85d \uc131\ub2a5\uc5d0 \uc720\ub9ac\ud569\ub2c8\ub2e4.<\/p>\n<p>\ub108\ubb34 \ub85c\uadf8 \uc2a4\uc704\uce58\uac00 \uc790\uc8fc \uc77c\uc5b4\ub098\uba74 \uc544\uce74\uc774\ube59 \ubc0f \uccb4\ud06c\ud3ec\uc778\ud2b8\uac00 \uc790\uc8fc \ubc1c\uc0dd\ud558\uac8c \ub418\ubbc0\ub85c archiver \ud504\ub85c\uc138\uc2a4\uc640 DBWR \ud504\ub85c\uc138\uc2a4\uac00 \ubc14\ube60\uc9d1\ub2c8\ub2e4.<\/p>\n<p>v$log_history \ubdf0\ub97c \uc870\ud68c\ud574\ubcf4\uba74 \ub85c\uadf8 \uc2a4\uc704\uce58\uac00 \uc5bc\ub9c8\ub098 \uc790\uc8fc \uc77c\uc5b4\ub098\ub294\uc9c0 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uc624\ub77c\ud074\uc758 \uad8c\uace0\uc548\uc740 20\ubd84\uc5d0 \ud55c\ubc88\uc529 \uc77c\uc5b4\ub098\ub294 \uac83\uc785\ub2c8\ub2e4. \uc774 \uad8c\uace0\uc548\uc744 \ubc18\ub4dc\uc2dc \uc900\uc218\ud560 \ud544\uc694\ub294 \uc5c6\uc9c0\ub9cc \uc801\uc5b4\ub3c4 5~10\ubd84 \uc0ac\uc774\uc5d0 \ud55c\ubc88\uc529 \ub85c\uadf8 \uc2a4\uc704\uce58\uac00 \uc77c\uc5b4\ub098\ub3c4\ub85d \uc124\uc815\ud574\uc8fc\ub294 \uac83\uc744 \uad8c\uc7a5\ud569\ub2c8\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Redo \ub85c\uadf8\uac00 \ucee4\uc838\uc11c \ubd88\ub9ac\ud55c \uc810\uc740 instance recovery \uc2dc\uac04\uc785\ub2c8\ub2e4<\/strong>.<\/p>\n<p>&nbsp;<\/p>\n<p>\uc989, \uc5b4\ub5a4 \uc774\uc720\ub85c \uc624\ub77c\ud074 \uc778\uc2a4\ud134\uc2a4\uac00 crash\ub418\uc5b4 Startup \uc2dc \ubcf5\uad6c\ud558\uace0 \uc62c\ub77c\uc640\uc57c\ud560 \ub54c \uae30\ub3d9 \uc2dc\uac04\uc774 \ub354 \uae38\uc5b4\uc9c8 \uc218 \uc788\uc2b5\ub2c8\ub2e4\ub9cc&#8230;<\/p>\n<p>\uc0ac\uc2e4 \uc774\uac83\ub3c4 \ub108\ubb34 \uac71\uc815\ud560 \ud544\uc694\uac00 \uc5c6\uc2b5\ub2c8\ub2e4. \uc815\ub9d0 instance recovery time\uc774 \uac71\uc815\ub41c\ub2e4\uba74 fast_start_mttr_target \ud30c\ub77c\ubbf8\ud130\ub97c \ud65c\uc6a9\ud574\ubcfc \uac83\uc744 \uad8c\uace0 \ub4dc\ub9bd\ub2c8\ub2e4.<\/p>\n<p><span style=\"color: #ff0000;\"><strong>\ucd5c\uadfc \uacbd\ud5a5\uc740 Redo \ud06c\uae30\ub97c \uc218\ubc31 \uba54\uac00\uc5d0\uc11c \uc218 \uc2ed \uae30\uac00\ubc14\uc774\ud2b8\uae4c\uc9c0 \uc124\uc815\ud558\ub294 \uacbd\uc6b0\uac00 \ub9ce\uc2b5\ub2c8\ub2e4. <\/strong><\/span><\/p>\n<p><strong>Redo\uac00 \uc9c0\ub098\uce58\uac8c \uc791\uc73c\uba74log file switch completion \ub4f1 \ub300\uae30 \uc774\ubca4\ud2b8\uac00 \ubb38\uc81c\uac00 \ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p>====<\/p>\n<p>&nbsp;<\/p>\n<p><strong><u>\uc624\ub77c\ud074 \uacf5\uc2dd \ub9e4\ub274\uc5bc\uc5d0\uc11c\ub3c4 \ub2e4\uc74c\uacfc \uac19\uc774 \uad8c\uace0\ud558\uace0 \uc788\uc2b5\ub2c8\ub2e4.<\/u><\/strong><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>\ub2e4\uc74c\uc740 \ub0b4\uc6a9\uc744 \ubc88\uc5ed\ud55c \uac83\uc785\ub2c8\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<p>&#8220;Database writer(dbwr)\uc640 archive \ud504\ub85c\uc138\uc2a4\uc758 \ub3d9\uc791\uc774 redo \ub85c\uadf8 \ud06c\uae30\uc5d0 \ub2ec\ub824\uc788\uae30 \ub54c\ubb38\uc5d0 Redo \ub85c\uadf8 \ud30c\uc77c\uc758 \ud06c\uae30\ub294 \uc131\ub2a5\uc5d0 \uc601\ud5a5\uc744 \ubbf8\uce60 \uc218 \uc788\ub2e4.<\/p>\n<p>\uc77c\ubc18\uc801\uc73c\ub85c Redo \ub85c\uadf8 \ud30c\uc77c\uc758 \ud06c\uae30\uac00 \ud074\uc218\ub85d \ub354 \ub098\uc740 \uc131\ub2a5\uc744 \uc81c\uacf5\ud55c\ub2e4. \ubcf4\ud1b5 \uc774\ud558\uc758 \ud06c\uae30\ub85c \uc124\uc815\ub41c \ub85c\uadf8 \ud30c\uc77c\uc740 \uccb4\ud06c\ud3ec\uc778\ud2b8 \ud65c\ub3d9\uc744 \uc99d\uac00\uc2dc\ud0a4\uace0 \uc131\ub2a5\uc744 \uac10\uc18c\uc2dc\ud0a8\ub2e4.<\/p>\n<p>redo \ub85c\uadf8 \ud30c\uc77c\uc758 \ud06c\uae30\uac00 LGWR \uc131\ub2a5\uc5d0 \uc601\ud5a5\uc744 \ubbf8\uce58\uc9c0\ub294 \uc54a\uc9c0\ub9cc, DBWR\uc640 \uccb4\ud06c\ud3ec\uc778\ud2b8 \ub3d9\uc791\uc5d0\ub294 \uc601\ud5a5\uc744 \ubbf8\uce60 \uc218 \uc788\ub2e4. \uccb4\ud06c\ud3ec\uc778\ud2b8 \uc8fc\uae30\ub294 \ub85c\uadf8 \ud30c\uc77c \ud06c\uae30\uc640<\/p>\n<p>FAST_START_MTTR_TARGET\uc758 \uc124\uc815\uc744 \ud3ec\ud568\ud55c \uc5ec\ub7ec \uc694\uc18c\uc5d0 \uc758\ud574 \uc601\ud5a5\uc744 \ubc1b\ub294\ub2e4. \ub9cc\uc57d \uc778\uc2a4\ud134\uc2a4 \ubcf5\uad6c \uc2dc\uac04\uc744 \uc81c\ud55c\ud558\uae30 \uc704\ud574 FAST_START_MTTR_TARGET \ud30c\ub77c\ubbf8\ud130\ub97c \uc124\uc815\ud588\ub2e4\uba74,<\/p>\n<p>\uc624\ub77c\ud074 \ub370\uc774\ud130\ubca0\uc774\uc2a4\ub294 \uc790\ub3d9\uc73c\ub85c \ud544\uc694\ud55c \ub9cc\ud07c \uc790\uc8fc \uccb4\ud06c \ud3ec\uc778\ud2b8\ub97c \uc2dc\ub3c4\ud55c\ub2e4.<\/p>\n<p>\uc774 \uc870\uac74 \ud558\uc5d0\uc11c \ub85c\uadf8 \ud30c\uc77c\uc758 \ud06c\uae30\ub294 \uc791\uac8c \uc124\uc815\ub41c \ub85c\uadf8 \ud30c\uc77c \ub54c\ubb38\uc5d0 \ucd94\uac00 \uccb4\ud06c\ud3ec\uc778\ud2b8\uac00 \uc77c\uc5b4\ub098\uc9c0 \uc54a\uc744 \ub9cc\ud07c \ucda9\ubd84\ud788 \ucee4\uc57c \ud55c\ub2e4.<\/p>\n<p>\ucd5c\uc801\uc758 \ud06c\uae30\ub294 V$INSTANCE_RECOVERY \ubdf0\uc758 OPTIMAL_LOGFILE_SIZE \uce7c\ub7fc\uc744 \uc870\ud68c\ud558\uc5ec \uc5bb\uc744 \uc218 \uc788\ub2e4.<\/p>\n<p>\ub610\ud55c \uc624\ub77c\ud074 \uc5d4\ud130\ud504\ub77c\uc774\uc988 \uad00\ub9ac\uc790\uc758 Redo Log Groups \ud398\uc774\uc9c0\uc5d0\uc11c \ud06c\uae30\uc5d0 \ub300\ud55c \uc870\uc5b8\uc744 \uc5bb\uc744 \uc218 \uc788\ub2e4.<\/p>\n<p>\ucd5c\uc801\uc758 Redo \ub85c\uadf8 \ud30c\uc77c \ud06c\uae30\ub97c \uad8c\uace0\ud558\ub294 \uac83\uc774 \ud56d\uc0c1 \uac00\ub2a5\ud558\uc9c0\ub294 \uc54a\uc9c0\ub9cc, 100MB\uc5d0\uc11c \uc218 \uae30\uac00 \ubc14\uc774\ud2b8\uc758 \ubc94\uc704\ub85c Redo \ub85c\uadf8 \ud30c\uc77c\uc744 \uc124\uc815\ud558\ub294 \uac83\uc774 \uc801\ub2f9\ud558\ub2e4\uace0 \uc0dd\uac01\ub41c\ub2e4.<\/p>\n<p>\uc628\ub77c\uc778 Redo \ub85c\uadf8 \ud30c\uc77c\uc758 \ud06c\uae30\ub294 \uc2dc\uc2a4\ud15c\uc5d0\uc11c \uc0dd\uc131\ub418\ub294 redo\uc758 \uc591\uc5d0 \ub2ec\ub824\uc788\ub2e4. \ub300\ub7b5\uc801\uc778 \uad8c\uace0\uc548\uc740 <strong>20\ubd84 \ub9c8\ub2e4 \ub85c\uadf8 \uc2a4\uc704\uce58<\/strong>\uac00 \uc77c\uc5b4\ub098\ub3c4\ub85d \uc124\uc815\ud558\ub294 \uac83\uc774\ub2e4.&#8221;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/docs.oracle.com\/cd\/E11882_01\/server.112\/e41573\/build_db.htm#PFGRF013\">https:\/\/docs.oracle.com\/cd\/E11882_01\/server.112\/e41573\/build_db.htm#PFGRF013<\/a><\/p>\n<p>Home \/ Database \/ Oracle Database Online Documentation 11g Release 2 (11.2) \/ Database Administration<\/p>\n<p>Database Performance Tuning Guide<\/p>\n<p>4 Configuring a Database for Performance<\/p>\n<p>&nbsp;<\/p>\n<p>4.1.3\u00a0Sizing Redo Log Files<\/p>\n<p>The size of the redo log files can influence performance, because the behavior of the database writer and archiver processes depend on the redo log sizes. Generally, larger redo log files provide better performance. Undersized log files increase checkpoint activity and reduce performance.<\/p>\n<p>Although the size of the redo log files does not affect LGWR performance, it can affect DBWR and checkpoint behavior. Checkpoint frequency is affected by several factors, including log file size and the setting of the\u00a0FAST_START_MTTR_TARGET\u00a0initialization parameter. If the\u00a0FAST_START_MTTR_TARGET\u00a0parameter is set to limit the instance recovery time, Oracle Database automatically tries to checkpoint as frequently as necessary. Under this condition, the size of the log files should be large enough to avoid additional checkpointing due to under sized log files. The optimal size can be obtained by querying the\u00a0OPTIMAL_LOGFILE_SIZE\u00a0column from the\u00a0V$INSTANCE_RECOVERY\u00a0view. You can also obtain sizing advice on the\u00a0<strong>Redo<\/strong>\u00a0<strong>Log<\/strong>\u00a0<strong>Groups<\/strong>\u00a0page of Oracle Enterprise Manager.<\/p>\n<p>It may not always be possible to provide a specific size recommendation for redo log files, but redo log files in the range of 100 MB to a few gigabytes are considered reasonable. Size online redo log files according to the amount of redo your system generates. A rough guide is to switch log files at most once every 20 minutes.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ubcf4\ud1b5\uc758 \uc0ac\uc774\ud2b8\uc5d0\uc11c Redo log \ud06c\uae30\uc5d0 \ub300\ud574 \uc5b8\uae09\ud560 \ub54c\ub9c8\ub2e4 \ub108\ubb34 \ucee4\uc9c0\uba74 \uc131\ub2a5 \uc800\ud558\uac00 \uc77c\uc5b4\ub098\uc9c0 \uc54a\uc744\uae4c \uc6b0\ub824\ud558\ub294 \uacbd\uc6b0\ub97c \uc790\uc8fc \uc811\ud558\uac8c \ub429\ub2c8\ub2e4. \uadf8\ub7f0\ub370 \uc0ac\uc2e4 Redo \ub85c\uadf8\ub294 \ucee4\uc9c8\uc218\ub85d \uc131\ub2a5\uc5d0 \uc720\ub9ac\ud569\ub2c8\ub2e4. \ub108\ubb34 \ub85c\uadf8 \uc2a4\uc704\uce58\uac00 \uc790\uc8fc \uc77c\uc5b4\ub098\uba74 \uc544\uce74\uc774\ube59 \ubc0f \uccb4\ud06c\ud3ec\uc778\ud2b8\uac00 \uc790\uc8fc \ubc1c\uc0dd\ud558\uac8c \ub418\ubbc0\ub85c archiver \ud504\ub85c\uc138\uc2a4\uc640 DBWR \ud504\ub85c\uc138\uc2a4\uac00 \ubc14\ube60\uc9d1\ub2c8\ub2e4. v$log_history \ubdf0\ub97c \uc870\ud68c\ud574\ubcf4\uba74 \ub85c\uadf8 \uc2a4\uc704\uce58\uac00 \uc5bc\ub9c8\ub098 \uc790\uc8fc \uc77c\uc5b4\ub098\ub294\uc9c0 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc624\ub77c\ud074\uc758 \uad8c\uace0\uc548\uc740 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2631,"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":[9],"tags":[853,856,433,434],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/haisins.synology.me\/wordpress\/wp-content\/uploads\/2018\/02\/redo_archiving_neededa.png?fit=399%2C310&ssl=1","amp_enabled":true,"_links":{"self":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2630"}],"collection":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2630"}],"version-history":[{"count":1,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2630\/revisions"}],"predecessor-version":[{"id":2632,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2630\/revisions\/2632"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/media\/2631"}],"wp:attachment":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2630"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2630"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2630"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}