{"id":2698,"date":"2018-02-02T22:07:54","date_gmt":"2018-02-02T13:07:54","guid":{"rendered":"http:\/\/haisins.epac.to\/wordpress\/?p=2698"},"modified":"2018-02-02T22:07:54","modified_gmt":"2018-02-02T13:07:54","slug":"ora-1555-%ec%a1%b0%ec%b9%98%eb%b0%a9%eb%b2%95","status":"publish","type":"post","link":"http:\/\/haisins.synology.me\/wordpress\/?p=2698","title":{"rendered":"ORA-1555 \uc870\uce58\ubc29\ubc95"},"content":{"rendered":"
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ORA-1555 Snapshot Too Old \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\ub294 \uc6d0\uc778\uc740 \uc5ec\ub7ec\uac00\uc9c0\uac00 \uc788\uc744 \uc218 \uc788\ub2e4.<\/p>\n

\uc774\ub97c \uc774\ud574\ud558\uae30 \uc704\ud574\uc11c \uc624\ub77c\ud074\uc758 \ub0b4\ubd80 \uba54\uce74\ub2c8\uc998\uc5d0 \ub300\ud574\uc11c \uc54c\uc544\ubcfc \ud544\uc694\uac00 \uc788\ub2e4. \uc624\ub77c\ud074\uc740 \ud56d\uc0c1 Statement-Level Read Consistency\ub97c \uc720\uc9c0\ud55c\ub2e4. \uc989, \ud558\ub098\uc758 Query \uc5d0\uc11c \uc77d\uc5b4\ub4e4\uc774\ub294 \uac12\uc740 \uadf8 Query\uac00 \ubc1c\uc0dd\ud55c \uc2dc\uc810\uc758 \uac12, \uc989 Snapshot \uc744 \ubc18\uc601\ud55c\ub2e4. \ub530\ub77c\uc11c Query \uac00 \uc9c4\ud589\ub418\ub294 \ub3d9\uc548 \ub370\uc774\ud0c0\uac00 \ubcc0\ud558\ub354\ub77c\ub3c4 Query\uc758 \uacb0\uacfc\uac12\uc5d0\ub294 \uc544\ubb34\ub7f0 \uc601\ud5a5\uc744 \ub07c\uce58\uc9c0 \uc54a\ub294\ub2e4.<\/p>\n

\uc624\ub77c\ud074\uc740 \ud2b9\uc815\ud55c \uc2dc\uc810\uc744 SCN(System Change Number)\ub85c \uad00\ub9ac\ud55c\ub2e4. \ub2ec\ub9ac \ub9d0\ud558\uba74 SCN\uc740 \ud2b9\uc815\ud55c \uc2dc\uc810\uc5d0\uc11c \ub370\uc774\ud0c0\ubca0\uc774\uc2a4\uc758 \uc0c1\ud0dc\ub77c\uace0\ub3c4 \ud560 \uc218 \uc788\ub2e4. Read Consistency\ub97c \uc720\uc9c0\ud558\uae30 \uc704\ud558\uc5ec Query\uac00 \uc2e4\ud589\ub418\ub294 \uc21c\uac04 \ud574\ub2f9 \uc2dc\uc810\uc758 SCN\uc774 \uc138\ud305\ub41c\ub2e4. \uc5b4\ub5a0\ud55c Query\ub4e0 \uc870\ud68c \uc2dc\uc810 \uc774\ud6c4\uc758 SCN \uac12\uc744 \uac16\ub294 \ub370\uc774\ud0c0\ub97c \uc77d\uc5b4\ub4e4\uc5ec \uc11c\ub294 \uc548\ub41c\ub2e4.<\/p>\n

Read Consistent Snapshot\uc744 \uad6c\ud604\ud558\uae30 \uc704\ud55c \ubc29\ubc95\uc73c\ub85c \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uac00 \uc0ac\uc6a9\ub41c\ub2e4. \ub370\uc774\ud0c0\uac00 \ubcc0\uacbd\ub418\uba74 \ubcc0\uacbd\ub418\uae30 \uc774\uc804\uc758 \uac12\uc740 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc5d0 \uae30\ub85d\ub418\uace0 \ub370\uc774\ud0c0 \ube14\ub7ed \ud5e4\ub354\uc5d0\ub294 \ubcc0\uacbd\ub418\uae30 \uc774\uc804 \uac12\uc774 \uae30\ub85d\ub41c \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8 \ube14\ub7ed\uc758 \uc704\uce58\uac00 \uae30\ub85d\ub41c\ub2e4. \ubaa8\ub4e0 \ub370\uc774\ud0c0 \ube14\ub7ed\uc5d0\ub294 \uac00\uc7a5 \ucd5c\uadfc\uc758 \ucee4\ubc0b \uc2dc\uc810\uc758 SCN\uc774 \uae30\ub85d\ub418\uc5b4 \uc788\ub2e4. Query \uac00 \uc9c4\ud589\ub418\uba74 \ub370\uc774\ud0c0 \ube14\ub7ed\uc5d0\uc11c\ub294 Query\uc758 SCN \ubcf4\ub2e4 \uc774\uc804\uc758 SCN\uac12\uc744 \uac16\ub294 \ube14\ub7ed\ub9cc\uc774 \uc77d\ud600\uc9c0\uace0 \uadf8 \uc774\ud6c4\uc758 SCN \uac12\uc744 \uac16\ub294 \ube14\ub7ed\uacfc \ucee4\ubc0b\ub418\uc9c0 \uc54a\uc740 \uac12\uc744 \uac16\ub294 \ube14\ub7ed\uc5d0 \ub300\ud55c Query\ub294 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc5d0\uc11c \uc77d\ud600\uc9c0\uac8c \ub41c\ub2e4. \uc774 \ub54c \ub9cc\uc57d \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc5d0 \uc6d0\ud558\ub294 \ube14\ub7ed\uc774 \uc5c6\uc5b4\uc11c \uc77d\uc5b4\ub4e4\uc774 \ubabb\ud558\uac8c \ub418\uba74 ORA-1555 \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\uac8c \ub41c\ub2e4.<\/p>\n

\uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\ub294 \ud2b8\ub79c\uc7ad\uc158\uc774 \ub05d\ub098\uae30 \uc804\uae4c\uc9c0 \ubcc0\uacbd\ub41c \ub370\uc774\ud0c0\uc758 \uc6d0\ub798 \uc0c1\ud0dc\ub97c \uae30\ub85d\ud558\uace0 \uc788\ub2e4. \uadf8\ub7f0\ub370 \ud2b8\ub79c\uc7ad\uc158\uc774 \uc885\ub8cc\ub418\uba74 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc5d0 \uc758\ud574 \uc810\uc720\ub41c \uc601\uc5ed\uc740 Free \uc0c1\ud0dc\ub85c \ub418\uba74\uc11c \ub2e4\ub978 \ud2b8\ub79c\uc7ad\uc158\uc5d0 \uc758\ud574\uc11c \ub36e\uc5b4\uc50c\uc6cc\uc9c8 \ub3c4 \uc788\uac8c \ub41c\ub2e4. \ub530\ub77c\uc11c Query\uac00 \ud544\uc694\ub85c\ud558\ub294 \uac12\uc744 \uac00\uc9c4 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8 \ube14\ub7ed\uc774 \ub354 \uc774\uc0c1 \uc874\uc7ac\ud558\uc9c0 \uc54a\ub294 \uc0c1\ud669\uc5d0\uc11c \uadf8 \ube14\ub7ed\uc744 \uc694\uad6c\ud558\uac8c \ub418\uba74 ORA-1555 \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\uac8c \ub418\ub294 \uac83\uc774\ub2e4.<\/p>\n

ORA-1555 \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\ub294 \uacbd\uc6b0<\/p>\n

1. \ub370\uc774\ud0c0\uc758 \ubcc0\uacbd\uc774 \uc2ec\ud55c \ub370\uc774\ud0c0\ubca0\uc774\uc2a4\uc5d0\uc11c \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc758 \uac2f\uc218\uc640 \ud06c\uae30\uac00 \uc791\uc744 \uacbd\uc6b0\uc5d0 \ubc1c\uc0dd\ud55c\ub2e4. \ub9ce\uc740 \ud2b8\ub79c\uc7ad\uc158\uc774 \ub370\uc774\ud0c0\ub97c \uc790\uc8fc \ubcc0\uacbd\ud558\uace0 \ucee4\ubc0b\ud558\uac8c \ub418\uba74 \ucee4\ubc0b\ub41c \ud2b8\ub79c\uc7ad\uc158\uc774 \uc774\uc6a9\ud558\ub358 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8 \uacf5\uac04\uc744 \ub2e4\ub978 \ud2b8\ub79c\uc7ad\uc158\uc774 \uc774\uc6a9\ud558\uac8c \ub420 \uac00\ub2a5\uc131\uc774 \ub9ce\uc544\uc9c4\ub2e4.<\/p>\n

\ub530\ub77c\uc11c \uae34 Query\uc758 \uacbd\uc6b0 \uc6d0\ud558\ub294 \uac12\uc744 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uc5d0\uc11c \uc5bb\uace0\uc790 \ud560 \ub54c \uc774\ubbf8 \ub2e4\ub978 \ud2b8\ub79c\uc7ad\uc158\uc774 \uadf8 \uac12\uc774 \uc800\uc7a5\ub41c \uacf5\uac04\uc744 \uc774\uc6a9\ud574 \ubc84\ub9ac\ub294 \uacb0\uacfc\uac00 \ubc1c\uc0dd\ud560 \uc218 \uc788\ub2e4. \uc774\uc640\uac19\uc740 \uacbd\uc6b0\uc5d0\ub294 \ud06c\uae30\uac00 \ud070 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\ub97c \uc774\uc6a9\ud558\uba74 \uc5b4\ub290\uc815\ub3c4 \uc608\ubc29\uc774 \uac00\ub2a5\ud558\ub2e4.<\/p>\n

2. \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\uac00 \uc190\uc0c1\ub418\uc5b4 \uc77d\uc744 \uc218 \uc5c6\uac8c \ub41c \uacbd\uc6b0<\/p>\n

3. Fetch Across Commit<\/p>\n

\ud55c \ud14c\uc774\ube14\uc5d0 \ub300\ud558\uc5ec Query\uac00 \ucee4\uc11c\ub97c \uc5f4\uace0 \ub8e8\ud504 \ub0b4\uc5d0\uc11c \ub370\uc774\ud0c0\ub97c Fetch\ud558\uace0 \ubcc0\uacbd\ud558\uace0 \ucee4\ubc0b\ud558\ub294 \uacfc\uc815\uc5d0\uc11c \ubc1c\uc0dd\ud55c\ub2e4. \uc774 \uacbd\uc6b0\uc5d0\ub294 ORA-1555 \uc5d0\ub7ec\uac00 \uc790\uc8fc \ubc1c\uc0dd\ud560 \uc18c\uc9c0\uac00 \uc788\ub294\ub370 \uc608\ub97c \ub4e4\uc5b4 \ucee4\uc11c\uac00 SCN=10 \uc5d0 Open\ub418\uc5c8\ub2e4\uace0 \ud558\uc790. \ub530\ub77c\uc11c \uc774 \ucee4\uc11c\uc5d0 \uad00\ub828\ub41c Fetch\ub294 SCN<=10 \uc778 \ube14\ub7ed\ub9cc\uc744 \uc77d\uc5b4\ub4e4\uc5ec\uc57c \ud55c\ub2e4. \uc774<\/p>\n

\ud504\ub85c\uadf8\ub7a8\uc740 \ub370\uc774\ud0c0\ub97c Fetch \ud55c \ud6c4\uc5d0 \ubcc0\uacbd\ud558\uace0 \ub2e4\uc2dc \ucee4\ubc0b\ud558\ub294 \uacfc\uc815\uc744 \uacc4\uc18d \ubc18\ubcf5\ud558\ub294\ub370 SCN=20\uc5d0\uc11c \ucee4\ubc0b\ud588\ub2e4\uace0 \ud558\uc790. \ub9cc\uc57d \uc774\ud6c4\uc758 Query\uac00 \uc774\uc804\uc758 \ucee4\ubc0b\ub41c \ube14\ub7ed\uc758 \ub370\uc774\ud0c0\ub97c \uc694\uad6c\ud560 \uacbd\uc6b0 \uadf8 \uac12\uc774 \uc774\ubbf8 \ubcc0\uacbd\ub418\uc5c8\uc73c\ubbc0\ub85c \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8\ub97c \uac80\uc0c9 \ud558\uc9c0\ub9cc \ub9ce\uc740 \ubcc0\uacbd\uc774 \uc788\uc5b4\uc654\uae30 \ub54c\ubb38\uc5d0 SCN=10\uc778 \ube14\ub7ed\uc744 \ucc3e\uc9c0 \ubabb\ud558\uace0 ORA-1555 \uc5d0\ub7ec\ub97c \uc720\ubc1c\ud560 \uc218 \uc788\ub2e4. \uc774\ub97c \ubc29\uc9c0\ud558\uae30 \uc704\ud574\uc11c\ub294 \ucee4\uc11c\uac00 Open\ub41c \uc0c1\ud0dc\uc5d0\uc11c\ub294 \ucee4\ubc0b\uc744 \uc790\uc8fc\ud558\uc9c0 \uc54a\uace0 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8 \ud06c\uae30\ub97c \ud0a4\uc6cc \ub098\uac00\ub3c4\ub85d \ud55c\ub2e4.<\/p>\n

4. Fetch Across Commit \uc640 Delayed Block Clean Out<\/p>\n

Delayed Block Clean Out \ub3c4 \uc774 \uc5d0\ub7ec\ub97c \uc720\ubc1c\ud560 \uc218 \uc788\ub2e4. \ub370\uc774\ud0c0 \ube14\ub7ed\uc774 \ubcc0\uacbd\ub418\uace0 \ucee4\ubc0b\ub418\uba74 \uc624\ub77c\ud074\uc740 \uc5b8\ub450 \uc138\uadf8\uba3c\ud2b8 \ud5e4\ub354\uc5d0 \uadf8 \ud2b8\ub79c\uc7ad\uc158\uc774 \ucee4\ubc0b\ub418\uc5c8\ub2e4\uace0 \uae30\ub85d\ud558\uc9c0\ub9cc \ub370\uc774\ud0c0 \ube14\ub7ed\uc744 \ubc14\ub85c \ubcc0\uacbd\ud558\uc9c0\ub294 \uc54a\ub294\ub2e4 (Fast Commit). \uadf8\ub9ac\uace0 \ub2e4\uc74c \ud2b8\ub79c\uc7ad\uc158\uc774 \ubcc0\uacbd\ub41c \ube14\ub7ed\uc744 \uc694\uad6c\ud560 \ub54c\uc57c \ube44\ub85c\uc18c \ubcc0\uacbd \uc2dc\ud0a4\ub294\ub370 \uc774\ub97c Delayed Block Clean Out \uc774\ub77c\uace0 \ud55c\ub2e4.<\/p>\n

\uc608\ub97c \ub4e4\uc5b4 3 \uacfc \uac19\uc740 \uacbd\uc6b0\uc5d0\uc11c \ub450\uac1c\uc758 \ud14c\uc774\ube14\uc5d0 \ub300\ud55c Query\ub97c \uc54c\uc544\ubcf4\uc790.<\/p>\n

\uc989, \ud558\ub098\uc758 \ud14c\uc774\ube14\ub85c\ubd80\ud130 \ub370\uc774\ud0c0\ub97c Fetch \ud558\uace0 \ub2e4\ub978 \ud14c\uc774\ube14\uc758 \ub370\uc774\ud0c0\ub97c \ubcc0\uacbd\ud55c\ub2e4\uace0 \ud558\uc790. \ub370\uc774\ud0c0\uac00 \ud55c\ucabd \ud14c\uc774\ube14\uc5d0\uc11c \ucee4\ubc0b\ub418\uace0 \uc788\uc9c0\ub9cc \ub370\uc774\ud0c0\ub97c \uac00\uc838\uc624\ub294 \ud14c\uc774\ube14\uc5d0 \ub300\ud574\uc11c\ub294 Clean Out\uc774 \uc774\ub8e8\uc5b4\uc9c0\uc9c0 \uc54a\uc558\uae30 \ub54c\ubb38\uc5d0 ORA-1555 \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud560 \uc218 \uc788\ub2e4. \uc774 \ubb38\uc81c\ub294 \ucee4\uc11c\ub97c \uc0ac\uc6a9\ud558\uae30 \uc804\uc5d0 Full Table Scan\uc744<\/p>\n

\ud574\uc8fc\uba74 \uc608\ubc29\uc774 \uac00\ub2a5\ud558\ub2e4. \ucee4\uc11c\uac00 \uc624\ud508\ub41c \uc0c1 \uc5d0\uc11c\uc758 \ucee4\ubc0b\uc740 ANSI \ud45c\uc900\uc5d0\ub294 \ub4e4\uc5b4\uc788\uc9c0 \uc54a\uc9c0\ub9cc \uc624\ub77c\ud074\uc5d0\uc11c\ub294 \uc9c0\uc6d0\uc774 \ub41c\ub2e4. \ud558\uc9c0\ub9cc ORA-1555 \uc5d0\ub7ec\ub97c \uc77c\uc73c\ud0ac \uc218\ub3c4 \uc788\ub2e4\ub294 \uc810\uc5d0 \uc720\uc758\ud558\uc5ec\uc57c \ud55c\ub2e4.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

ORA-1555 Snapshot Too Old \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\ub294 \uc6d0\uc778\uc740 \uc5ec\ub7ec\uac00\uc9c0\uac00 \uc788\uc744 \uc218 \uc788\ub2e4. \uc774\ub97c \uc774\ud574\ud558\uae30 \uc704\ud574\uc11c \uc624\ub77c\ud074\uc758 \ub0b4\ubd80 \uba54\uce74\ub2c8\uc998\uc5d0 \ub300\ud574\uc11c \uc54c\uc544\ubcfc \ud544\uc694\uac00 \uc788\ub2e4. \uc624\ub77c\ud074\uc740 \ud56d\uc0c1 Statement-Level Read Consistency\ub97c \uc720\uc9c0\ud55c\ub2e4. \uc989, \ud558\ub098\uc758 Query \uc5d0\uc11c \uc77d\uc5b4\ub4e4\uc774\ub294 \uac12\uc740 \uadf8 Query\uac00 \ubc1c\uc0dd\ud55c \uc2dc\uc810\uc758 \uac12, \uc989 Snapshot \uc744 \ubc18\uc601\ud55c\ub2e4. \ub530\ub77c\uc11c Query \uac00 \uc9c4\ud589\ub418\ub294 \ub3d9\uc548 \ub370\uc774\ud0c0\uac00 \ubcc0\ud558\ub354\ub77c\ub3c4 Query\uc758 \uacb0\uacfc\uac12\uc5d0\ub294 \uc544\ubb34\ub7f0 \uc601\ud5a5\uc744 \ub07c\uce58\uc9c0 \uc54a\ub294\ub2e4. […]<\/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":[14],"tags":[885,887,886],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2698"}],"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=2698"}],"version-history":[{"count":1,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2698\/revisions"}],"predecessor-version":[{"id":2699,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2698\/revisions\/2699"}],"wp:attachment":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2698"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2698"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}