{"id":51590,"date":"2024-08-15T01:38:46","date_gmt":"2024-08-14T16:38:46","guid":{"rendered":"https:\/\/8gfg.shop\/blog\/development\/mysql-query-performance-issues-and-optimization-techniques"},"modified":"2024-08-15T01:38:46","modified_gmt":"2024-08-14T16:38:46","slug":"mysql-query-performance-issues-and-optimization-techniques","status":"publish","type":"post","link":"https:\/\/8gfg.shop\/blog\/development\/mysql-query-performance-issues-and-optimization-techniques","title":{"rendered":"MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95"},"content":{"rendered":"<ul class=\"toc_post_list\">\n<li>\n<h2>\ubaa9\ucc28<\/h2>\n<ul>\n<li><a href=\"#mysql%ec%9d%98-%ec%bf%bc%eb%a6%ac-%ec%84%b1%eb%8a%a5-%eb%ac%b8%ec%a0%9c%ec%99%80-%ec%b5%9c%ec%a0%81%ed%99%94-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95<\/a><\/li>\n<li><a href=\"#1-mysql-%ec%bf%bc%eb%a6%ac-%ec%84%b1%eb%8a%a5-%eb%ac%b8%ec%a0%9c%ec%9d%98-%ec%9d%b4%ed%95%b4-jFPBDzzAll\">1. MySQL \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc758 \uc774\ud574<\/a><\/li>\n<li><a href=\"#2-%ec%bf%bc%eb%a6%ac-%ec%b5%9c%ec%a0%81%ed%99%94%eb%a5%bc-%ec%9c%84%ed%95%9c-%ea%b8%b0%eb%b3%b8-%ec%9b%90%ec%b9%99-jFPBDzzAll\">2. \ucffc\ub9ac \ucd5c\uc801\ud654\ub97c \uc704\ud55c \uae30\ubcf8 \uc6d0\uce59<\/a><\/li>\n<li><a href=\"#3-%ec%9d%b8%eb%8d%b1%ec%8a%a4-%ec%b5%9c%ec%a0%81%ed%99%94-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">3. \uc778\ub371\uc2a4 \ucd5c\uc801\ud654 \uae30\ubc95<\/a><\/li>\n<li><a href=\"#4-%ec%bf%bc%eb%a6%ac-%eb%a6%ac%ed%8c%a9%ed%86%a0%eb%a7%81-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">4. \ucffc\ub9ac \ub9ac\ud329\ud1a0\ub9c1 \uae30\ubc95<\/a><\/li>\n<li><a href=\"#5-%ed%95%98%eb%93%9c%ec%9b%a8%ec%96%b4-%eb%b0%8f-%ec%84%9c%eb%b2%84-%ec%84%a4%ec%a0%95-%ec%b5%9c%ec%a0%81%ed%99%94-jFPBDzzAll\">5. \ud558\ub4dc\uc6e8\uc5b4 \ubc0f \uc11c\ubc84 \uc124\uc815 \ucd5c\uc801\ud654<\/a><\/li>\n<li><a href=\"#6-%ec%bf%bc%eb%a6%ac-%ec%ba%90%ec%8b%b1-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">6. \ucffc\ub9ac \uce90\uc2f1 \uae30\ubc95<\/a><\/li>\n<li><a href=\"#7-%eb%aa%a8%eb%8b%88%ed%84%b0%eb%a7%81-%eb%b0%8f-%ec%84%b1%eb%8a%a5-%eb%b6%84%ec%84%9d-%eb%8f%84%ea%b5%ac-jFPBDzzAll\">7. \ubaa8\ub2c8\ud130\ub9c1 \ubc0f \uc131\ub2a5 \ubd84\uc11d \ub3c4\uad6c<\/a><\/li>\n<li><a href=\"#8-%ea%b2%b0%eb%a1%a0-%eb%b0%8f-%ed%96%a5%ed%9b%84-%ec%a0%84%eb%a7%9d-jFPBDzzAll\">8. \uacb0\ub860 \ubc0f \ud5a5\ud6c4 \uc804\ub9dd<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h1 id=\"mysql%ec%9d%98-%ec%bf%bc%eb%a6%ac-%ec%84%b1%eb%8a%a5-%eb%ac%b8%ec%a0%9c%ec%99%80-%ec%b5%9c%ec%a0%81%ed%99%94-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95<\/h1>\n<p>MySQL\uc740 \uc138\uacc4\uc5d0\uc11c \uac00\uc7a5 \ub110\ub9ac \uc0ac\uc6a9\ub418\ub294 \uc624\ud508 \uc18c\uc2a4 \uad00\uacc4\ud615 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uad00\ub9ac \uc2dc\uc2a4\ud15c(RDBMS) \uc911 \ud558\ub098\uc785\ub2c8\ub2e4. \ub9ce\uc740 \uae30\uc5c5\uacfc \uac1c\ubc1c\uc790\ub4e4\uc774 MySQL\uc744 \uc120\ud0dd\ud558\ub294 \uc774\uc720\ub294 \uadf8 \uc548\uc815\uc131\uacfc \uc131\ub2a5, \uadf8\ub9ac\uace0 \ub2e4\uc591\ud55c \uae30\ub2a5 \ub54c\ubb38\uc785\ub2c8\ub2e4. \uadf8\ub7ec\ub098 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc758 \uc131\ub2a5\uc740 \ucffc\ub9ac\uc758 \ud6a8\uc728\uc131\uc5d0 \ud06c\uac8c \uc758\uc874\ud558\uba70, \ube44\ud6a8\uc728\uc801\uc778 \ucffc\ub9ac\ub294 \uc2dc\uc2a4\ud15c\uc758 \uc804\uccb4 \uc131\ub2a5\uc744 \uc800\ud558\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubcf8 \uae00\uc5d0\uc11c\ub294 MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \uc774\ub97c \ucd5c\uc801\ud654\ud558\uae30 \uc704\ud55c \ub2e4\uc591\ud55c \uae30\ubc95\uc5d0 \ub300\ud574 \uc2ec\ub3c4 \uc788\uac8c \ub2e4\ub8e8\uc5b4 \ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<h2 id=\"1-mysql-%ec%bf%bc%eb%a6%ac-%ec%84%b1%eb%8a%a5-%eb%ac%b8%ec%a0%9c%ec%9d%98-%ec%9d%b4%ed%95%b4-jFPBDzzAll\">1. MySQL \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc758 \uc774\ud574<\/h2>\n<p>\ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\ub294 \uc5ec\ub7ec \uac00\uc9c0 \uc6d0\uc778\uc73c\ub85c \ubc1c\uc0dd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc758 \uad6c\uc870, \uc778\ub371\uc2a4 \uc124\uc815, \ucffc\ub9ac \uc791\uc131 \ubc29\uc2dd \ub4f1\uc774 \uadf8 \uc608\uc785\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 MySQL \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc758 \uc8fc\uc694 \uc6d0\uc778\uacfc \uadf8\ub85c \uc778\ud574 \ubc1c\uc0dd\ud560 \uc218 \uc788\ub294 \ubb38\uc81c\ub97c \uc0b4\ud3b4\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8\ub85c, \ube44\ud6a8\uc728\uc801\uc778 \ucffc\ub9ac \uc791\uc131\uc774 \uc788\uc2b5\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4, SELECT \ubb38\uc5d0\uc11c \ubd88\ud544\uc694\ud55c \uceec\ub7fc\uc744 \uc120\ud0dd\ud558\uac70\ub098, WHERE \uc808\uc5d0\uc11c \uc778\ub371\uc2a4\ub97c \ud65c\uc6a9\ud558\uc9c0 \uc54a\ub294 \uc870\uac74\uc744 \uc0ac\uc6a9\ud558\ub294 \uacbd\uc6b0 \uc131\ub2a5 \uc800\ud558\uac00 \ubc1c\uc0dd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ub7ec\ud55c \ucffc\ub9ac\ub294 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uac00 \ub354 \ub9ce\uc740 \ub370\uc774\ud130\ub97c \uc77d\uace0 \ucc98\ub9ac\ud574\uc57c \ud558\ubbc0\ub85c, \uc751\ub2f5 \uc2dc\uac04\uc774 \uae38\uc5b4\uc9c8 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8\ub85c, \uc778\ub371\uc2a4\uc758 \ubd80\uc7ac \ub610\ub294 \uc798\ubabb\ub41c \uc778\ub371\uc2a4 \uc124\uc815\uc774 \uc788\uc2b5\ub2c8\ub2e4. \uc778\ub371\uc2a4\ub294 \ub370\uc774\ud130 \uac80\uc0c9 \uc18d\ub3c4\ub97c \ub192\uc774\ub294 \ub370 \uc911\uc694\ud55c \uc5ed\ud560\uc744 \ud569\ub2c8\ub2e4. \uadf8\ub7ec\ub098 \uc778\ub371\uc2a4\uac00 \uc5c6\uac70\ub098 \uc798\ubabb \uc124\uc815\ub41c \uacbd\uc6b0, MySQL\uc740 \uc804\uccb4 \ud14c\uc774\ube14\uc744 \uc2a4\uce94\ud574\uc57c \ud558\ubbc0\ub85c \uc131\ub2a5\uc774 \uc800\ud558\ub429\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8\ub85c, \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc758 \uad6c\uc870\uc801 \ubb38\uc81c\ub3c4 \uc131\ub2a5\uc5d0 \uc601\ud5a5\uc744 \ubbf8\uce60 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4, \uc815\uaddc\ud654\uac00 \uacfc\ub3c4\ud558\uac8c \uc774\ub8e8\uc5b4\uc9c4 \uacbd\uc6b0 \uc870\uc778\uc774 \ub9ce\uc544\uc838 \ucffc\ub9ac \uc131\ub2a5\uc774 \uc800\ud558\ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubc18\ub300\ub85c, \uc815\uaddc\ud654\uac00 \ubd80\uc871\ud55c \uacbd\uc6b0 \ub370\uc774\ud130 \uc911\ubcf5\uc774 \ubc1c\uc0dd\ud558\uc5ec \uc800\uc7a5 \uacf5\uac04\uc744 \ub0ad\ube44\ud558\uac8c \ub429\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \uc11c\ubc84\uc758 \ud558\ub4dc\uc6e8\uc5b4 \uc0ac\uc591\uc774\ub098 \uc124\uc815\ub3c4 \uc131\ub2a5\uc5d0 \ud070 \uc601\ud5a5\uc744 \ubbf8\uce69\ub2c8\ub2e4. CPU, \uba54\ubaa8\ub9ac, \ub514\uc2a4\ud06c I\/O \uc18d\ub3c4 \ub4f1\uc774 \ubaa8\ub450 \ucffc\ub9ac \uc131\ub2a5\uc5d0 \uc601\ud5a5\uc744 \ubbf8\uce58\ubbc0\ub85c, \uc801\uc808\ud55c \ud558\ub4dc\uc6e8\uc5b4\uc640 \uc124\uc815\uc774 \ud544\uc694\ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"2-%ec%bf%bc%eb%a6%ac-%ec%b5%9c%ec%a0%81%ed%99%94%eb%a5%bc-%ec%9c%84%ed%95%9c-%ea%b8%b0%eb%b3%b8-%ec%9b%90%ec%b9%99-jFPBDzzAll\">2. \ucffc\ub9ac \ucd5c\uc801\ud654\ub97c \uc704\ud55c \uae30\ubcf8 \uc6d0\uce59<\/h2>\n<p>\ucffc\ub9ac \ucd5c\uc801\ud654\ub294 \uc131\ub2a5 \ubb38\uc81c\ub97c \ud574\uacb0\ud558\uae30 \uc704\ud55c \uccab \ubc88\uc9f8 \ub2e8\uacc4\uc785\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 \ucffc\ub9ac \ucd5c\uc801\ud654\ub97c \uc704\ud55c \uae30\ubcf8 \uc6d0\uce59\uc744 \uc18c\uac1c\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8 \uc6d0\uce59\uc740 \ud544\uc694\ud55c \ub370\uc774\ud130\ub9cc \uc120\ud0dd\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. SELECT \ubb38\uc5d0\uc11c \ubaa8\ub4e0 \uceec\ub7fc\uc744 \uc120\ud0dd\ud558\ub294 \ub300\uc2e0 \ud544\uc694\ud55c \uceec\ub7fc\ub9cc \uc120\ud0dd\ud558\uc5ec \ub370\uc774\ud130 \uc804\uc1a1\ub7c9\uc744 \uc904\uc774\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4:<\/p>\n<pre><code>SELECT name, age FROM users;<\/code><\/pre>\n<p>\uc704\uc640 \uac19\uc774 \ud544\uc694\ud55c \uceec\ub7fc\ub9cc \uc120\ud0dd\ud558\uba74 \uc131\ub2a5\uc774 \ud5a5\uc0c1\ub429\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8 \uc6d0\uce59\uc740 WHERE \uc808\uc5d0\uc11c \uc778\ub371\uc2a4\ub97c \ud65c\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. \uc778\ub371\uc2a4\ub97c \ud65c\uc6a9\ud558\uba74 \ub370\uc774\ud130 \uac80\uc0c9 \uc18d\ub3c4\uac00 \ube68\ub77c\uc9c0\ubbc0\ub85c, WHERE \uc808\uc5d0\uc11c \uc778\ub371\uc2a4\uac00 \uc124\uc815\ub41c \uceec\ub7fc\uc744 \uc0ac\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8 \uc6d0\uce59\uc740 \uc870\uc778\uc744 \ucd5c\uc18c\ud654\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. \uc870\uc778\uc774 \ub9ce\uc544\uc9c8\uc218\ub85d \ucffc\ub9ac \uc131\ub2a5\uc774 \uc800\ud558\ub418\ubbc0\ub85c, \uac00\ub2a5\ud55c \ud55c \uc870\uc778\uc744 \uc904\uc774\uace0 \uc11c\ube0c\ucffc\ub9ac\ub97c \ud65c\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub124 \ubc88\uc9f8 \uc6d0\uce59\uc740 LIMIT \uc808\uc744 \uc0ac\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. \ub300\ub7c9\uc758 \ub370\uc774\ud130\ub97c \ucc98\ub9ac\ud560 \ub54c\ub294 LIMIT \uc808\uc744 \uc0ac\uc6a9\ud558\uc5ec \ud544\uc694\ud55c \ub370\uc774\ud130\ub9cc \uac00\uc838\uc624\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \ucffc\ub9ac \uc2e4\ud589 \uacc4\ud68d\uc744 \ubd84\uc11d\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4. MySQL\uc758 EXPLAIN \uba85\ub839\uc5b4\ub97c \uc0ac\uc6a9\ud558\uc5ec \ucffc\ub9ac \uc2e4\ud589 \uacc4\ud68d\uc744 \ud655\uc778\ud558\uace0, \ube44\ud6a8\uc728\uc801\uc778 \ubd80\ubd84\uc744 \ucc3e\uc544 \ucd5c\uc801\ud654\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<h2 id=\"3-%ec%9d%b8%eb%8d%b1%ec%8a%a4-%ec%b5%9c%ec%a0%81%ed%99%94-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">3. \uc778\ub371\uc2a4 \ucd5c\uc801\ud654 \uae30\ubc95<\/h2>\n<p>\uc778\ub371\uc2a4\ub294 MySQL \ucffc\ub9ac \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \ub370 \uc911\uc694\ud55c \uc5ed\ud560\uc744 \ud569\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 \uc778\ub371\uc2a4 \ucd5c\uc801\ud654 \uae30\ubc95\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8\ub85c, \uc801\uc808\ud55c \uc778\ub371\uc2a4\ub97c \uc124\uc815\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4. \uc778\ub371\uc2a4\ub294 \uc790\uc8fc \uac80\uc0c9\ub418\ub294 \uceec\ub7fc\uc5d0 \uc124\uc815\ud558\ub294 \uac83\uc774 \uc88b\uc73c\uba70, \ubcf5\ud569 \uc778\ub371\uc2a4\ub97c \ud65c\uc6a9\ud558\uc5ec \uc5ec\ub7ec \uceec\ub7fc\uc744 \ub3d9\uc2dc\uc5d0 \uc778\ub371\uc2f1\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8\ub85c, \uc778\ub371\uc2a4\uc758 \uc218\ub97c \ucd5c\uc18c\ud654\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4. \ub108\ubb34 \ub9ce\uc740 \uc778\ub371\uc2a4\ub294 \ub370\uc774\ud130 \uc0bd\uc785 \ubc0f \uc218\uc815 \uc2dc \uc131\ub2a5 \uc800\ud558\ub97c \ucd08\ub798\ud560 \uc218 \uc788\uc73c\ubbc0\ub85c, \ud544\uc694\ud55c \uc778\ub371\uc2a4\ub9cc \uc124\uc815\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8\ub85c, \uc778\ub371\uc2a4\uc758 \ud1b5\uacc4\ub97c \uc8fc\uae30\uc801\uc73c\ub85c \uc5c5\ub370\uc774\ud2b8\ud574\uc57c \ud569\ub2c8\ub2e4. MySQL\uc740 \ud1b5\uacc4\ub97c \uae30\ubc18\uc73c\ub85c \ucffc\ub9ac \uc2e4\ud589 \uacc4\ud68d\uc744 \uacb0\uc815\ud558\ubbc0\ub85c, \ud1b5\uacc4\uac00 \uc624\ub798\ub418\uba74 \ube44\ud6a8\uc728\uc801\uc778 \uc2e4\ud589 \uacc4\ud68d\uc774 \uc0dd\uc131\ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub124 \ubc88\uc9f8\ub85c, \uc778\ub371\uc2a4 \uc0ac\uc6a9 \uc5ec\ubd80\ub97c \ubaa8\ub2c8\ud130\ub9c1\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4. \uc0ac\uc6a9\ub418\uc9c0 \uc54a\ub294 \uc778\ub371\uc2a4\ub294 \uc0ad\uc81c\ud558\uc5ec \uc131\ub2a5\uc744 \uac1c\uc120\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \uc778\ub371\uc2a4 \uc870\uc815 \ud6c4\uc5d0\ub294 \ubc18\ub4dc\uc2dc \uc131\ub2a5 \ud14c\uc2a4\ud2b8\ub97c \uc218\ud589\ud558\uc5ec \ucd5c\uc801\ud654 \ud6a8\uacfc\ub97c \ud655\uc778\ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"4-%ec%bf%bc%eb%a6%ac-%eb%a6%ac%ed%8c%a9%ed%86%a0%eb%a7%81-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">4. \ucffc\ub9ac \ub9ac\ud329\ud1a0\ub9c1 \uae30\ubc95<\/h2>\n<p>\ucffc\ub9ac \ub9ac\ud329\ud1a0\ub9c1\uc740 \uae30\uc874 \ucffc\ub9ac\ub97c \uac1c\uc120\ud558\uc5ec \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \uacfc\uc815\uc785\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 \ucffc\ub9ac \ub9ac\ud329\ud1a0\ub9c1 \uae30\ubc95\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8 \uae30\ubc95\uc740 \uc11c\ube0c\ucffc\ub9ac\ub97c \ud65c\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. \uc11c\ube0c\ucffc\ub9ac\ub97c \uc0ac\uc6a9\ud558\uba74 \ubcf5\uc7a1\ud55c \uc870\uc778\uc744 \uc904\uc77c \uc218 \uc788\uc73c\uba70, \uc131\ub2a5\uc744 \uac1c\uc120\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<pre><code>SELECT name FROM users WHERE id IN (SELECT user_id FROM orders WHERE amount &gt; 100);<\/code><\/pre>\n<p>\ub450 \ubc88\uc9f8 \uae30\ubc95\uc740 UNION \ub300\uc2e0 UNION ALL\uc744 \uc0ac\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. UNION\uc740 \uc911\ubcf5\ub41c \uacb0\uacfc\ub97c \uc81c\uac70\ud558\ubbc0\ub85c \uc131\ub2a5\uc774 \uc800\ud558\ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc911\ubcf5\ub41c \uacb0\uacfc\uac00 \ud544\uc694 \uc5c6\ub294 \uacbd\uc6b0 UNION ALL\uc744 \uc0ac\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n<pre><code>SELECT name FROM users WHERE age &gt; 30 UNION ALL SELECT name FROM users WHERE age &lt; 20;<\/code><\/pre>\n<p>\uc138 \ubc88\uc9f8 \uae30\ubc95\uc740 CASE \ubb38\uc744 \ud65c\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. CASE \ubb38\uc744 \uc0ac\uc6a9\ud558\uba74 \uc5ec\ub7ec \uc870\uac74\uc744 \ud558\ub098\uc758 \ucffc\ub9ac\ub85c \ucc98\ub9ac\ud560 \uc218 \uc788\uc5b4 \uc131\ub2a5\uc744 \uac1c\uc120\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<pre><code>SELECT name, CASE WHEN age &gt; 30 THEN 'Adult' ELSE 'Minor' END AS age_group FROM users;<\/code><\/pre>\n<p>\ub124 \ubc88\uc9f8 \uae30\ubc95\uc740 JOIN \ub300\uc2e0 EXISTS\ub97c \uc0ac\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. EXISTS\ub294 \uc870\uac74\uc774 \ucc38\uc778 \uacbd\uc6b0\uc5d0\ub9cc \uacb0\uacfc\ub97c \ubc18\ud658\ud558\ubbc0\ub85c \uc131\ub2a5\uc774 \ud5a5\uc0c1\ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<pre><code>SELECT name FROM users WHERE EXISTS (SELECT 1 FROM orders WHERE orders.user_id = users.id);<\/code><\/pre>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \ucffc\ub9ac\ub97c \uc8fc\uae30\uc801\uc73c\ub85c \ub9ac\ubdf0\ud558\uace0 \ub9ac\ud329\ud1a0\ub9c1\ud558\uc5ec \uc131\ub2a5\uc744 \uc9c0\uc18d\uc801\uc73c\ub85c \uac1c\uc120\ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"5-%ed%95%98%eb%93%9c%ec%9b%a8%ec%96%b4-%eb%b0%8f-%ec%84%9c%eb%b2%84-%ec%84%a4%ec%a0%95-%ec%b5%9c%ec%a0%81%ed%99%94-jFPBDzzAll\">5. \ud558\ub4dc\uc6e8\uc5b4 \ubc0f \uc11c\ubc84 \uc124\uc815 \ucd5c\uc801\ud654<\/h2>\n<p>\ucffc\ub9ac \uc131\ub2a5\uc740 \ud558\ub4dc\uc6e8\uc5b4\uc640 \uc11c\ubc84 \uc124\uc815\uc5d0\ub3c4 \ud06c\uac8c \uc758\uc874\ud569\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 \ud558\ub4dc\uc6e8\uc5b4 \ubc0f \uc11c\ubc84 \uc124\uc815 \ucd5c\uc801\ud654 \uae30\ubc95\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8\ub85c, \uba54\ubaa8\ub9ac\ub97c \ucda9\ubd84\ud788 \ud655\ubcf4\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4. MySQL\uc740 \uba54\ubaa8\ub9ac\ub97c \ub9ce\uc774 \uc0ac\uc6a9\ud558\ub294 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc774\ubbc0\ub85c, \ucda9\ubd84\ud55c \uba54\ubaa8\ub9ac\ub97c \ud655\ubcf4\ud558\uc5ec \uce90\uc2dc\ub97c \ud65c\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8\ub85c, SSD\ub97c \uc0ac\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4. SSD\ub294 \ub514\uc2a4\ud06c I\/O \uc18d\ub3c4\uac00 \ube60\ub974\ubbc0\ub85c, \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc131\ub2a5\uc744 \ud06c\uac8c \ud5a5\uc0c1\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8\ub85c, MySQL \uc124\uc815 \ud30c\uc77c(my.cnf)\uc744 \ucd5c\uc801\ud654\ud574\uc57c \ud569\ub2c8\ub2e4. innodb_buffer_pool_size, query_cache_size \ub4f1\uc758 \uc124\uc815 \uac12\uc744 \uc870\uc815\ud558\uc5ec \uc131\ub2a5\uc744 \uac1c\uc120\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub124 \ubc88\uc9f8\ub85c, \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc0e4\ub529\uc744 \uace0\ub824\ud574\uc57c \ud569\ub2c8\ub2e4. \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc0e4\ub529\uc740 \ub370\uc774\ud130\ub97c \uc5ec\ub7ec \uc11c\ubc84\uc5d0 \ubd84\uc0b0 \uc800\uc7a5\ud558\uc5ec \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \ubc29\ubc95\uc785\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \ubaa8\ub2c8\ud130\ub9c1 \ub3c4\uad6c\ub97c \ud65c\uc6a9\ud558\uc5ec \uc11c\ubc84 \uc131\ub2a5\uc744 \uc9c0\uc18d\uc801\uc73c\ub85c \ubaa8\ub2c8\ud130\ub9c1\ud558\uace0, \ubb38\uc81c\uac00 \ubc1c\uc0dd\ud560 \uacbd\uc6b0 \uc989\uc2dc \ub300\uc751\ud560 \uc218 \uc788\ub3c4\ub85d \ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"6-%ec%bf%bc%eb%a6%ac-%ec%ba%90%ec%8b%b1-%ea%b8%b0%eb%b2%95-jFPBDzzAll\">6. \ucffc\ub9ac \uce90\uc2f1 \uae30\ubc95<\/h2>\n<p>\ucffc\ub9ac \uce90\uc2f1\uc740 \ub3d9\uc77c\ud55c \ucffc\ub9ac\uc5d0 \ub300\ud55c \uacb0\uacfc\ub97c \uc800\uc7a5\ud558\uc5ec \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \uae30\ubc95\uc785\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 \ucffc\ub9ac \uce90\uc2f1 \uae30\ubc95\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8\ub85c, MySQL\uc758 \ucffc\ub9ac \uce90\uc2dc \uae30\ub2a5\uc744 \ud65c\uc6a9\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. MySQL\uc740 \ucffc\ub9ac \uacb0\uacfc\ub97c \uba54\ubaa8\ub9ac\uc5d0 \uc800\uc7a5\ud558\uc5ec \ub3d9\uc77c\ud55c \ucffc\ub9ac\uac00 \uc2e4\ud589\ub420 \ub54c \ube60\ub974\uac8c \uacb0\uacfc\ub97c \ubc18\ud658\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8\ub85c, \uc560\ud50c\ub9ac\ucf00\uc774\uc158 \ub808\ubca8\uc5d0\uc11c \uce90\uc2f1\uc744 \uad6c\ud604\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. Redis\ub098 Memcached\uc640 \uac19\uc740 \uce90\uc2dc \uc11c\ubc84\ub97c \uc0ac\uc6a9\ud558\uc5ec \ucffc\ub9ac \uacb0\uacfc\ub97c \uc800\uc7a5\ud558\uace0, \uc560\ud50c\ub9ac\ucf00\uc774\uc158\uc5d0\uc11c \uc774\ub97c \ud65c\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8\ub85c, \uce90\uc2dc \ubb34\ud6a8\ud654 \uc804\ub7b5\uc744 \uc138\uc6cc\uc57c \ud569\ub2c8\ub2e4. \ub370\uc774\ud130\uac00 \ubcc0\uacbd\ub420 \ub54c \uce90\uc2dc\ub97c \ubb34\ud6a8\ud654\ud558\uc5ec \ucd5c\uc2e0 \ub370\uc774\ud130\ub97c \ubc18\uc601\ud558\ub3c4\ub85d \ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<p>\ub124 \ubc88\uc9f8\ub85c, \uce90\uc2dc \uc0ac\uc6a9\ub960\uc744 \ubaa8\ub2c8\ud130\ub9c1\ud558\uc5ec \uce90\uc2dc \ud6a8\uc728\uc131\uc744 \ubd84\uc11d\ud558\uace0 \uac1c\uc120\ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \uce90\uc2dc\ub97c \uc0ac\uc6a9\ud560 \ub54c\ub294 \uba54\ubaa8\ub9ac \uc0ac\uc6a9\ub7c9\uacfc \uc751\ub2f5 \uc2dc\uac04\uc744 \uace0\ub824\ud558\uc5ec \uc801\uc808\ud55c \ud06c\uae30\ub97c \uc124\uc815\ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"7-%eb%aa%a8%eb%8b%88%ed%84%b0%eb%a7%81-%eb%b0%8f-%ec%84%b1%eb%8a%a5-%eb%b6%84%ec%84%9d-%eb%8f%84%ea%b5%ac-jFPBDzzAll\">7. \ubaa8\ub2c8\ud130\ub9c1 \ubc0f \uc131\ub2a5 \ubd84\uc11d \ub3c4\uad6c<\/h2>\n<p>\ucffc\ub9ac \uc131\ub2a5\uc744 \ucd5c\uc801\ud654\ud558\uae30 \uc704\ud574\uc11c\ub294 \ubaa8\ub2c8\ud130\ub9c1\uacfc \ubd84\uc11d\uc774 \ud544\uc218\uc801\uc785\ub2c8\ub2e4. \uc774 \uc139\uc158\uc5d0\uc11c\ub294 MySQL\uc758 \ubaa8\ub2c8\ud130\ub9c1 \ubc0f \uc131\ub2a5 \ubd84\uc11d \ub3c4\uad6c\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\uccab \ubc88\uc9f8 \ub3c4\uad6c\ub294 MySQL Workbench\uc785\ub2c8\ub2e4. MySQL Workbench\ub294 \ucffc\ub9ac \uc2e4\ud589 \uacc4\ud68d\uc744 \uc2dc\uac01\uc801\uc73c\ub85c \ubd84\uc11d\ud560 \uc218 \uc788\ub294 \ub3c4\uad6c\ub85c, \ube44\ud6a8\uc728\uc801\uc778 \ucffc\ub9ac\ub97c \uc27d\uac8c \ucc3e\uc544\ub0bc \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub450 \ubc88\uc9f8 \ub3c4\uad6c\ub294 Percona Toolkit\uc785\ub2c8\ub2e4. Percona Toolkit\uc740 \ub2e4\uc591\ud55c MySQL \uad00\ub9ac \ub3c4\uad6c\ub97c \uc81c\uacf5\ud558\uba70, \ucffc\ub9ac \uc131\ub2a5 \ubd84\uc11d \ubc0f \ucd5c\uc801\ud654\ub97c \uc9c0\uc6d0\ud569\ub2c8\ub2e4.<\/p>\n<p>\uc138 \ubc88\uc9f8 \ub3c4\uad6c\ub294 pt-query-digest\uc785\ub2c8\ub2e4. \uc774 \ub3c4\uad6c\ub294 MySQL \ub85c\uadf8 \ud30c\uc77c\uc744 \ubd84\uc11d\ud558\uc5ec \uac00\uc7a5 \ub290\ub9b0 \ucffc\ub9ac\ub97c \ucc3e\uc544\ub0b4\uace0, \uc774\ub97c \ucd5c\uc801\ud654\ud558\ub294 \ub370 \ub3c4\uc6c0\uc744 \uc90d\ub2c8\ub2e4.<\/p>\n<p>\ub124 \ubc88\uc9f8 \ub3c4\uad6c\ub294 New Relic\uacfc \uac19\uc740 APM(Application Performance Monitoring) \ub3c4\uad6c\uc785\ub2c8\ub2e4. \uc774\ub7ec\ud55c \ub3c4\uad6c\ub294 \uc560\ud50c\ub9ac\ucf00\uc774\uc158\uc758 \uc131\ub2a5\uc744 \ubaa8\ub2c8\ud130\ub9c1\ud558\uace0, \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640\uc758 \uc0c1\ud638\uc791\uc6a9\uc744 \ubd84\uc11d\ud558\uc5ec \ubcd1\ubaa9 \ud604\uc0c1\uc744 \ucc3e\uc544\ub0bc \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<p>\ub9c8\uc9c0\ub9c9\uc73c\ub85c, \uc774\ub7ec\ud55c \ub3c4\uad6c\ub4e4\uc744 \ud65c\uc6a9\ud558\uc5ec \uc8fc\uae30\uc801\uc73c\ub85c \uc131\ub2a5 \ubd84\uc11d\uc744 \uc218\ud589\ud558\uace0, \ubb38\uc81c\ub97c \uc0ac\uc804\uc5d0 \uc608\ubc29\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4.<\/p>\n<h2 id=\"8-%ea%b2%b0%eb%a1%a0-%eb%b0%8f-%ed%96%a5%ed%9b%84-%ec%a0%84%eb%a7%9d-jFPBDzzAll\">8. \uacb0\ub860 \ubc0f \ud5a5\ud6c4 \uc804\ub9dd<\/h2>\n<p>MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95\uc5d0 \ub300\ud574 \uc0b4\ud3b4\ubcf4\uc558\uc2b5\ub2c8\ub2e4. \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc131\ub2a5\uc740 \ube44\uc988\ub2c8\uc2a4\uc758 \uc131\uacf5\uc5d0 \ud070 \uc601\ud5a5\uc744 \ubbf8\uce58\ubbc0\ub85c, \uc9c0\uc18d\uc801\uc778 \ubaa8\ub2c8\ud130\ub9c1\uacfc \ucd5c\uc801\ud654\uac00 \ud544\uc694\ud569\ub2c8\ub2e4. \uc55e\uc73c\ub85c\ub3c4 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uae30\uc220\uc740 \ubc1c\uc804\ud560 \uac83\uc774\uba70, \uc0c8\ub85c\uc6b4 \ucd5c\uc801\ud654 \uae30\ubc95\uacfc \ub3c4\uad6c\ub4e4\uc774 \ub4f1\uc7a5\ud560 \uac83\uc785\ub2c8\ub2e4.<\/p>\n<p>\uacb0\ub860\uc801\uc73c\ub85c, MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\ub97c \ud574\uacb0\ud558\uae30 \uc704\ud574\uc11c\ub294 \uae30\ubcf8 \uc6d0\uce59\uc744 \uc900\uc218\ud558\uace0, \uc778\ub371\uc2a4 \ucd5c\uc801\ud654 \ubc0f \ucffc\ub9ac \ub9ac\ud329\ud1a0\ub9c1 \uae30\ubc95\uc744 \ud65c\uc6a9\ud574\uc57c \ud569\ub2c8\ub2e4. \ub610\ud55c \ud558\ub4dc\uc6e8\uc5b4 \ubc0f \uc11c\ubc84 \uc124\uc815 \ucd5c\uc801\ud654\uc640 \ucffc\ub9ac \uce90\uc2f1 \uae30\ubc95\uc744 \ud1b5\ud574 \uc131\ub2a5\uc744 \uadf9\ub300\ud654\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub9c8\uc9c0\ub9c9\uc73c\ub85c, \ubaa8\ub2c8\ud130\ub9c1 \ubc0f \uc131\ub2a5 \ubd84\uc11d \ub3c4\uad6c\ub97c \ud65c\uc6a9\ud558\uc5ec \uc9c0\uc18d\uc801\uc73c\ub85c \uc131\ub2a5\uc744 \uac1c\uc120\ud574 \ub098\uac00\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<p>\uc774 \uae00\uc774 MySQL \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95\uc5d0 \ub300\ud55c \uc774\ud574\ub97c \ub192\uc774\ub294 \ub370 \ub3c4\uc6c0\uc774 \ub418\uc5c8\uae30\ub97c \ubc14\ub78d\ub2c8\ub2e4. \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uad00\ub9ac\uc790\ub294 \ud56d\uc0c1 \ucd5c\uc2e0 \uae30\uc220\uacfc \uae30\ubc95\uc5d0 \ub300\ud55c \ud559\uc2b5\uc744 \uac8c\uc744\ub9ac\ud558\uc9c0 \uc54a\uc544\uc57c \ud558\uba70, \uc774\ub97c \ud1b5\ud574 \ub354 \ub098\uc740 \uc2dc\uc2a4\ud15c\uc744 \uad6c\ucd95\ud560 \uc218 \uc788\uc744 \uac83\uc785\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ubaa9\ucc28 MySQL\uc758 \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc640 \ucd5c\uc801\ud654 \uae30\ubc95 1. MySQL \ucffc\ub9ac \uc131\ub2a5 \ubb38\uc81c\uc758 \uc774\ud574 2. \ucffc\ub9ac [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":33704,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1957],"tags":[2058,2100,2136],"class_list":["post-51590","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-development","tag-application","tag-mysql","tag-performance"],"acf":[],"_links":{"self":[{"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/posts\/51590","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/comments?post=51590"}],"version-history":[{"count":0,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/posts\/51590\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/media\/33704"}],"wp:attachment":[{"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/media?parent=51590"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/categories?post=51590"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/8gfg.shop\/blog\/wp-json\/wp\/v2\/tags?post=51590"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}