{"id":2675,"date":"2018-02-02T21:31:32","date_gmt":"2018-02-02T12:31:32","guid":{"rendered":"http:\/\/haisins.epac.to\/wordpress\/?p=2675"},"modified":"2018-02-02T21:31:32","modified_gmt":"2018-02-02T12:31:32","slug":"db_file_multiblock_read_count-%ec%99%80-db-%ec%84%b1%eb%8a%a5-%ea%b4%80%ea%b3%84","status":"publish","type":"post","link":"http:\/\/haisins.synology.me\/wordpress\/?p=2675","title":{"rendered":"DB_FILE_MULTIBLOCK_READ_COUNT \uc640 DB \uc131\ub2a5 \uad00\uacc4"},"content":{"rendered":"<p>* db_file_multiblock_read_count\u00a0 \ud30c\ub77c\ubbf8\ud130\ub294 \ud55c\ubc88\uc758 I\/O \uc791\uc5c5\uc73c\ub85c \uc77d\uc5b4\ub4e4\uc774\ub294 \ucd5c\ub300 \ube14\ub7ed \uc218\ub97c \uac00\ub9ac\ud0a4\uba70 Multi Block I\/O \uc5d0 \uad00\ub828\ub41c \ud30c\ub77c\ubbf8\ud130\uc774\ub2e4.<\/p>\n<p>\ub514\ud3f4\ud2b8 \uac12\uc740 O\/S\uc5d0 \ub530\ub77c\uc11c \ub2e4\ub978\ub370 \ubcf4\ud1b5 db_block_buffers\uc640 Processes\uc5d0 \uc758\ud574\uc11c \uacb0\uc815\ub418\uba70 4~32 \uc815\ub3c4\uac00 \ub9ce\uc774 \uc0ac\uc6a9\ub41c\ub2e4.<\/p>\n<p>\uc774 \uac12\uc744 \ud0a4\uc6b0\uace0 SORT\/MERGE\u00a0 \ub97c \uc774\uc6a9\ud558\ub294 \uac83\uc774 Nested\u00a0 Loop\ub97c \uc774\uc6a9\ud558\ub294 \uacbd\uc6b0 \ubcf4\ub2e4 \ud37c\ud3ec\uba3c\uc2a4\uac00 \uc99d\uac00\ud558\ub294\uac00 \ud558\ub294 \ubb38\uc81c\ub294\u00a0 Query\uc758 \uc885\ub958\uc640 \uc77d\uc5b4\ub4e4\uc774\ub294 \ub370\uc774\ud0c0\uc758 \uc591(\uc804\uccb4\uc5d0 \ub300\ud55c Percentage)\uc5d0\u00a0 \ub530\ub77c\uc11c \ub2ec\ub77c\uc9c0\uac8c \ub41c\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<p>\uc989, \uc774 \uac12\uc774 \ud06c\uba74 \ud55c\ubc88\uc758 I\/O\ub85c \uc5ec\ub7ec\uac1c\uc758 \ube14\ub7ed\uc744 \uc77d\u00a0 \uc624\ubbc0\ub85c Full Table Scan\uc2dc \uc5d0\ub294 \ud37c\ud3ec\uba3c\uc2a4\uac00 \uc99d\uac00\ud55c\ub2e4. \ud558\uc9c0\ub9cc \ud2b9\uc815 \ube14\ub7ed\ub9cc\uc774 \ud544\uc694\ud55c \uacbd\uc6b0\uc5d0 \ubd88\ud544\uc694\ud55c \ube14\ub7ed\uae4c\uc9c0 \ud568\uaed8 \uc77d\uc5b4\ub4e4\uc774\ubbc0\ub85c \ub514\uc2a4\ud06c\ub97c \uc77d\ub294 \uc2dc\uac04\uc774 \uc99d\uac00\ud560 \ubfd0<\/p>\n<p>\uc544\ub2c8\ub77c \ud06c\uae30\uac00 \ud55c\uc815\ub41c\u00a0 Buffer Pool\uc744 \ub9ce\uc774 \ucc28\uc9c0\ud574 \ubc84\ub9bc\uc73c\ub85c\uc368 \uc790\uc8fc \uc4f0\uc774\ub294 \ub370\uc774\ud0c0\ub97c \ubc00\uc5b4\ub0b4\uc5b4 \uc624\ud788\ub824 Cache\uc758 \ud6a8\uc728\uc744 \ub5a8\uc5b4\ub728\ub9ac\ub294 \uacb0\uacfc\ub97c \uac00\uc838\uc62c \uc218\ub3c4 \uc788\uc73c\ubbc0\ub85c \uc791\uc5c5\ud2b9\uc131\uc5d0 \ub530\ub77c\uc11c \uc801\uc808\ud55c \uac12\uc744 \uc138\ud305\ud558\uc5ec\uc57c \ud55c\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<p>\uc624\ub77c\ud074\uc758 Optimizer\ub294 \uc774 \uac12\uc774 \ud06c\uba74 \uc791\uc5c5\uc758 \ud6a8\uc728\uc131\uc744 \uc704\ud574\uc11c Full Table Scan \uc744 \uc120\ud0dd\ud560\u00a0 \uac00\ub2a5\uc131\uc774 \ucee4\uc9c0\uac8c \ub41c\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>* db_file_multiblock_read_count\u00a0 \ud30c\ub77c\ubbf8\ud130\ub294 \ud55c\ubc88\uc758 I\/O \uc791\uc5c5\uc73c\ub85c \uc77d\uc5b4\ub4e4\uc774\ub294 \ucd5c\ub300 \ube14\ub7ed \uc218\ub97c \uac00\ub9ac\ud0a4\uba70 Multi Block I\/O \uc5d0 \uad00\ub828\ub41c \ud30c\ub77c\ubbf8\ud130\uc774\ub2e4. \ub514\ud3f4\ud2b8 \uac12\uc740 O\/S\uc5d0 \ub530\ub77c\uc11c \ub2e4\ub978\ub370 \ubcf4\ud1b5 db_block_buffers\uc640 Processes\uc5d0 \uc758\ud574\uc11c \uacb0\uc815\ub418\uba70 4~32 \uc815\ub3c4\uac00 \ub9ce\uc774 \uc0ac\uc6a9\ub41c\ub2e4. \uc774 \uac12\uc744 \ud0a4\uc6b0\uace0 SORT\/MERGE\u00a0 \ub97c \uc774\uc6a9\ud558\ub294 \uac83\uc774 Nested\u00a0 Loop\ub97c \uc774\uc6a9\ud558\ub294 \uacbd\uc6b0 \ubcf4\ub2e4 \ud37c\ud3ec\uba3c\uc2a4\uac00 \uc99d\uac00\ud558\ub294\uac00 \ud558\ub294 \ubb38\uc81c\ub294\u00a0 Query\uc758 \uc885\ub958\uc640 \uc77d\uc5b4\ub4e4\uc774\ub294 \ub370\uc774\ud0c0\uc758 \uc591(\uc804\uccb4\uc5d0 \ub300\ud55c Percentage)\uc5d0\u00a0 \ub530\ub77c\uc11c 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