{"id":693,"date":"2009-08-30T19:10:41","date_gmt":"2009-08-30T11:10:41","guid":{"rendered":"http:\/\/orczhou.com\/?p=693"},"modified":"2025-03-18T14:17:03","modified_gmt":"2025-03-18T06:17:03","slug":"innodb_flush_method-file-io","status":"publish","type":"post","link":"https:\/\/www.orczhou.com\/index.php\/2009\/08\/innodb_flush_method-file-io\/","title":{"rendered":"innodb_flush_method \u4e0e File I\/O"},"content":{"rendered":"\n<p>\u9676\u65b9\u5728\u300ainnodb_flush_method\u5e26\u6765\u7684\u6027\u80fd\u5f71\u54cd\u300b\u4e2d\u4ece\u5b9e\u9a8c\u89d2\u5ea6\u6bd4\u8f83\u4e86fdatasync\uff0cO_DSYNC\u548cO_DIRECT\u5728\u6027\u80fd\u4e0a\u7684\u5dee\u5f02\u3002\u672c\u6587\u5c06\u8bd5\u56fe\u4eceLinux\/Unix&#8221;\u6587\u4ef6I\/O&#8221;\uff08unbuffered I\/O\uff09\u7684\u89d2\u5ea6\u6765\u89e3\u91cainnodb_flush_method\u662f\u5982\u4f55\u5f71\u54cdMySQL\u7684I\/O\u3002<sup>\u3010\u9644\u5f551\u3011<\/sup><\/p>\n\n\n\n<p>innodb_flush_log_at_trx_commit \u53c2\u6570\u786e\u5b9a\u65e5\u5fd7\u6587\u4ef6 <strong><span style=\"text-decoration: underline;\">\u4f55\u65f6<\/span> <\/strong>write\u3001flush\u3002innodb_flush_method\u5219\u786e\u5b9a\u65e5\u5fd7\u53ca\u6570\u636e\u6587\u4ef6 <strong><span style=\"text-decoration: underline;\">\u5982\u4f55<\/span><\/strong> write\u3001flush\u3002\u5728Linux\u4e0b\uff0cinnodb_flush_method \u53ef\u4ee5\u53d6\u5982\u4e0b\u503c\uff1afdatasync, O_DSYNC, O_DIRECT\uff0c\u90a3\u8fd9\u4e09\u4e2a\u503c\u5206\u522b\u662f\u5982\u4f55\u5f71\u54cd\u6587\u4ef6\u5199\u5165\u7684\uff1f\u9996\u5148\u6211\u4eec\u9700\u8981\u5148\u6765\u4e86\u89e3Linux\u7684\u6587\u4ef6I\/O\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u3002<br><\/p>\n\n\n\n<!--more-->\n\n\n\n<p><br>\u5148\u6765\u770b\u770bLinux\/Unix\u6587\u4ef6I\/O\u7684\u4e00\u4e2a\u5178\u578b\u4f8b\u5b50\uff1a\uff08Linux 2.6.24\u6d4b\u8bd5\uff0cgcc\u7f16\u8bd1\uff09<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"c\" class=\"language-c\">\/**\n\tA test about syscall of File I\/O\n\tAuthor:supu@TaobaoDBA\n\tsupu@taobao.com http:\/\/orczhou.com http:\/\/www.taobaodba.com\n*\/\n\n#include   \"stdlib.h\"           \/* for exit *\/\n#include   \"unistd.h\"           \/* for write fdatasync*\/\n#include    \"fcntl.h\"           \/* for open  *\/\nint main(void){\n\tint fd;\n\tif((fd=open(\"\/home\/zzx\/test.file\",O_WRONLY|O_APPEND|O_DSYNC))&lt;0){\n\t\texit(1);\n        }\n        char buff[]=\"abcdef\";\n        if(write(fd,buff,6)!= 6){\n                exit(2);\n        }\n        if(fdatasync(fd)==-1){\n                exit(3);\n        }\n        exit(0);\n}<\/code><\/pre>\n\n\n\n<p>\u7a0b\u5e8f\u63cf\u8ff0\u4e86\u4e00\u822c\u7684\u6587\u4ef6I\/O\u64cd\u4f5c\u7684\u4e09\u4e2a\u8fc7\u7a0bopen\u3001write\u3001fdatasync\uff0c\u5206\u522b\u662f\u6253\u5f00\u6587\u4ef6\u3001\u5199\u6587\u4ef6\u3001flush\u64cd\u4f5c\uff08\u5c06\u6587\u4ef6\u7f13\u5b58\u5237\u5230\u78c1\u76d8\u4e0a\uff09\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u4e00\u3001Open\u9636\u6bb5<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"c\" class=\"language-c\">    open(\"test.file\",O_WRONLY|O_APPDENT|O_SYNC))<\/code><\/pre>\n\n\n\n<p>\u7cfb\u7edf\u8c03\u7528Open\u4f1a\u4e3a\u8be5\u8fdb\u7a0b\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26fd<sup>\u3010\u9644\u5f552\u3011<\/sup>\u3002\u8fd9\u91cc\u4f7f\u7528\u4e86<code>O_WRONLY|O_APPDENT|O_SYNC<\/code>\u6253\u5f00\u6587\u4ef6:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><code>O_WRONLY<\/code>\u8868\u793a\u6211\u4eec\u4ee5&#8221;\u5199&#8221;\u7684\u65b9\u5f0f\u6253\u5f00\uff0c\u544a\u8bc9\u5185\u6838\u6211\u4eec\u9700\u8981\u5411\u6587\u4ef6\u4e2d\u5199\u5165\u6570\u636e\uff1b<\/li>\n\n\n\n<li><code>O_APPDENT<\/code>\u544a\u8bc9\u5185\u6838\u4ee5&#8221;\u8ffd\u52a0&#8221;\u7684\u65b9\u5f0f\u5199\u6587\u4ef6\uff1b<\/li>\n\n\n\n<li><code>O_DSYNC<\/code>\u544a\u8bc9\u5185\u6838\uff0c\u5f53\u5411\u6587\u4ef6\u5199\u5165\u6570\u636e\u7684\u65f6\u5019\uff0c\u53ea\u6709\u5f53\u6570\u636e\u5199\u5230\u4e86\u78c1\u76d8\u65f6\uff0c\u5199\u5165\u64cd\u4f5c\u624d\u7b97\u5b8c\u6210\uff08write\u624d\u8fd4\u56de\u6210\u529f\uff09\u3002\u548c<code>O_DSYNC<\/code>\u540c\u7c7b\u7684\u6587\u4ef6\u6807\u5fd7\uff0c\u8fd8\u6709<code>O_SYNC,O_RSYNC\uff0cO_DIRECT<\/code>\u3002\n<ul class=\"wp-block-list\">\n<li><code>O_SYNC<\/code>\u6bd4<code>O_DSYNC<\/code>\u66f4\u4e25\u683c\uff0c\u4e0d\u4ec5\u8981\u6c42\u6570\u636e\u5df2\u7ecf\u5199\u5230\u4e86\u78c1\u76d8\uff0c\u800c\u4e14\u5bf9\u5e94\u7684\u6570\u636e\u6587\u4ef6\u7684\u5c5e\u6027\uff08\u4f8b\u5982\u6587\u4ef6\u957f\u5ea6\u7b49\uff09\u4e5f\u9700\u8981\u66f4\u65b0\u5b8c\u6210\u624d\u7b97write\u64cd\u4f5c\u6210\u529f\u3002\u53ef\u89c1<code>O_SYNC<\/code>\u8f83\u4e4b<code>O_DSYNC<\/code>\u8981\u591a\u505a\u4e00\u4e9b\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li><code>O_RSYNC<\/code>\u8868\u793a\u6587\u4ef6\u8bfb\u53d6\u65f6\uff0c\u8be5\u6587\u4ef6\u7684<code>OS cache<\/code>\u5fc5\u987b\u5df2\u7ecf\u5168\u90e8flush\u5230\u78c1\u76d8\u4e86<sup>\u3010\u9644\u5f553\u3011<\/sup>\uff1b<\/li>\n\n\n\n<li>\u5982\u679c\u4f7f\u7528<code>O_DIREC<\/code>T\u6253\u5f00\u6587\u4ef6\uff0c\u5219\u8bfb\/\u5199\u64cd\u4f5c\u90fd\u4f1a\u8df3\u8fc7<code>OS cache<\/code>\uff0c\u76f4\u63a5\u5728device\uff08disk\uff09\u4e0a\u8bfb\/\u5199\u3002\u56e0\u4e3a\u6ca1\u6709\u4e86OS cache\uff0c\u6240\u4ee5\u4f1a<code>O_DIRECT<\/code>\u964d\u4f4e\u6587\u4ef6\u7684\u987a\u5e8f\u8bfb\u5199\u7684\u6548\u7387\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h4 class=\"wp-block-heading\">\u4e8c\u3001Write\u9636\u6bb5<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"c\" class=\"language-c\">    write(fd,buf,6)<\/code><\/pre>\n\n\n\n<p>\u5728\u4f7f\u7528open\u6253\u5f00\u6587\u4ef6\u83b7\u5f97\u6587\u4ef6\u63cf\u8ff0\u7b26\u4e4b\u540e\uff0c\u6211\u4eec\u5c31\u53ef\u4ee5\u8c03\u7528write\u51fd\u6570\u6765\u5199\u5165\u6570\u636e\u4e86\uff0cwrite\u4f1a\u6839\u636e\u524d\u9762\u7684open\u53c2\u6570\u4e0d\u540c\uff0c\u800c\u8868\u73b0\u4e0d\u540c\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u4e09\u3001Flush\u9636\u6bb5<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"bash\" class=\"language-bash\">    fdatasync(fd) == -1<\/code><\/pre>\n\n\n\n<p><code>write<\/code>\u64cd\u4f5c\u540e\uff0c\u6211\u4eec\u8fd8\u8c03\u7528\u4e86<code>fdatasync<\/code>\u6765\u786e\u4fdd\u6587\u4ef6\u6570\u636e<code>flush<\/code>\u5230\u4e86<code>disk<\/code>\u4e0a\u3002<code>fdatasync<\/code>\u8fd4\u56de\u6210\u529f\u540e\uff0c\u90a3\u4e48\u53ef\u4ee5\u8ba4\u4e3a\u6570\u636e\u5df2\u7ecf\u5199\u5230\u4e86\u78c1\u76d8\u4e0a\u3002\u50cf\u8fd9\u6837\u7684flush\u7684\u51fd\u6570\u8fd8\u6709fsync\u3001sync\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li> <code>Fsync<\/code>\u548c<code>fdatasync<\/code>\u7684\u533a\u522b\u7b49\u540c\u4e8eO_SYNC\u548cO_DSYNC\u7684\u533a\u522b\u3002<\/li>\n\n\n\n<li><code>Sync<\/code>\u51fd\u6570\u8868\u793a\u5c06\u6587\u4ef6\u5728OS cache\u4e2d\u7684\u6570\u636e\u6392\u5165\u5199\u961f\u5217\uff0c\u5e76\u4e0d\u786e\u8ba4\u662f\u5426\u771f\u7684\u5199\u78c1\u76d8\u4e86\uff0c\u6240\u4ee5sync\u5e76\u4e0d\u53ef\u4ee5\u9760\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u5ffd\u7565\u6587\u4ef6\u6253\u5f00\u7684\u8fc7\u7a0b\uff0c\u901a\u5e38\u6211\u4eec\u4f1a\u8bf4\u201c\u5199\u6587\u4ef6\u201d\u6709\u4e24\u4e2a\u9636\u6bb5\uff0c\u4e00\u4e2a\u662f\u8c03\u7528write\u6211\u4eec\u79f0\u4e3a\u5199\u6570\u636e\u9636\u6bb5\uff08\u5176\u5b9e\u662f\u53d7open\u7684\u53c2\u6570\u5f71\u54cd\uff09\uff0c\u8c03\u7528fsync\uff08\u6216\u8005fdatasync\uff09\u6211\u4eec\u79f0\u4e3aflush\u9636\u6bb5\u3002<\/p>\n\n\n\n<p>\u56de\u5230MySQL\uff0c\u53c2\u6570<code>Innodb_flush_method<\/code>(Linux)\u53ef\u4ee5\u8bbe\u5b9a\u4e3a\uff1a<code>Fdatasync\u3001O_DSYNC\u3001O_DIRECT<\/code>\u3002\u6211\u4eec\u770b\u770b\u8fd9\u4e2a\u4e09\u4e2a\u53c2\u6570\u662f\u5982\u4f55\u5f71\u54cd\u7a0b\u5e8fMySQL\u5bf9\u65e5\u5fd7\u548c\u6570\u636e\u6587\u4ef6\u7684\u64cd\u4f5c\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td>&nbsp;<\/td><td>Open log<\/td><td>Flush log<\/td><td>Open datafile<\/td><td>Flush data<\/td><\/tr><tr><td>Fdatasync<\/td><td>&nbsp;<\/td><td><strong>fsync()<\/strong><\/td><td>&nbsp;<\/td><td><strong>fsync()<\/strong><\/td><\/tr><tr><td>O_DSYNC<\/td><td><strong>O_SYNC<\/strong><\/td><td>&nbsp;<\/td><td>&nbsp;<\/td><td><strong>fsync()<\/strong><\/td><\/tr><tr><td>O_DIRECT<\/td><td>&nbsp;<\/td><td><strong>fsync()<\/strong><\/td><td><code><strong>O_DIRECT<\/strong><\/code><\/td><td><strong>Fsync()<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>fdatasync\u88ab\u8ba4\u4e3a\u662f\u5b89\u5168\u7684\uff0c\u56e0\u4e3a\u5728MySQL\u603b\u4f1a\u8c03\u7528fsync\u6765flush\u6570\u636e\u3002\u4f7f\u7528O_DSYNC\u662f\u6709\u4e9b\u98ce\u9669\u7684\uff0c\u6709\u4e9bOS\u4f1a\u5ffd\u7565\u8be5\u53c2\u6570<strong>O_SYNC<\/strong>\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u770b\u5230O_DIRECT\u548cfdatasync\u548c\u5f88\u7c7b\u4f3c\uff0c\u4f46\u662f\u5b83\u4f1a\u4f7f\u7528<code><strong>O_DIRECT<\/strong><\/code>\u6765\u6253\u5f00\u6570\u636e\u6587\u4ef6\u3002\u6709\u6570\u636e\u8868\u660e\uff0c\u5982\u679c\u662f\u5927\u91cf\u968f\u673a\u5199\u5165\u64cd\u4f5c\uff0c<code><strong>O_DIRECT<\/strong><\/code>\u4f1a\u63d0\u5347\u6548\u7387\u3002\u4f46\u662f\u987a\u5e8f\u5199\u5165\u548c\u8bfb\u53d6\u6548\u7387\u90fd\u4f1a\u964d\u4f4e\u3002\u6240\u4ee5\u4f7f\u7528O_DIRECT\u9700\u8981\u8c28\u614e\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u53c2\u8003\u6587\u7ae0<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Unix\u73af\u5883\u9ad8\u7ea7\u7f16\u7a0b\uff08\u7b2c\u4e8c\u7248\uff09<\/li>\n\n\n\n<li><a href=\"http:\/\/rdc.taobao.com\/blog\/dba\/html\/296_innodb_flush_method_performance.html\">http:\/\/rdc.taobao.com\/blog\/dba\/html\/296_innodb_flush_method_performance.html<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/dev.mysql.com\/doc\/refman\/5.0\/en\/innodb-parameters.html\">http:\/\/dev.mysql.com\/doc\/refman\/5.0\/en\/innodb-parameters.html<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/www.ukuug.org\/events\/linux2001\/papers\/html\/AArcangeli-o_direct.html\">http:\/\/www.ukuug.org\/events\/linux2001\/papers\/html\/AArcangeli-o_direct.html<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/xiaomeng.yo2.cn\/articles\/buffered-io-and-non-buffered-io.html\">http:\/\/xiaomeng.yo2.cn\/articles\/buffered-io-and-non-buffered-io.html<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/articles.directorym.net\/Operating_Systems_System_Calls_and_IO-a894576.html\">http:\/\/articles.directorym.net\/Operating_Systems_System_Calls_and_IO-a894576.html<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/linux\/l-cn-read\/\">http:\/\/www.ibm.com\/developerworks\/cn\/linux\/l-cn-read\/<\/a><\/li>\n\n\n\n<li><a href=\"http:\/\/www.kernel.org\/doc\/man-pages\/online\/pages\/man2\/open.2.html\">http:\/\/www.kernel.org\/doc\/man-pages\/online\/pages\/man2\/open.2.html<\/a><\/li>\n\n\n\n<li>\u7cfb\u7edf\u8c03\u7528\uff1a<a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/linux\/kernel\/syscall\/part1\/index.html\">http:\/\/www.ibm.com\/developerworks\/cn\/linux\/kernel\/syscall\/part1\/index.html<\/a><\/li>\n<\/ol>\n\n\n\n<h4 class=\"wp-block-heading\">\u9644\u5f551: \u5173\u4e8e\u7cfb\u7edf\u8c03\u7528<\/h4>\n\n\n\n<p>\u672c\u7bc7\u6587\u7ae0\u9700\u8981\u4f60\u4e86\u89e3\u4ec0\u4e48\u662f\u201c\u7cfb\u7edf\u8c03\u7528\u201c\uff0c\u53c2\u8003\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/man7.org\/linux\/man-pages\/man2\/syscalls.2.html\">System Calls Manual at Linux manual page<\/a> <\/li>\n<\/ul>\n\n\n\n<p>\u53ef\u4ee5\u7b80\u5355\u7684\u7406\u89e3\u4e3a\uff1a\u201c\u7cfb\u7edf\u8c03\u7528\u201c\u662f\u5728 Linux \u5185\u6838\u4e4b\u4e0a\u7684\u4e00\u5c42\u5c01\u88c5\u3002\u7531\u5185\u6838\u76f4\u63a5\u63d0\u4f9b\u63a5\u53e3\uff0c\u201c\u7cfb\u7edf\u8c03\u7528\u201d\u9700\u8981\u9677\u5165\u5185\u6838\u6267\u884c\uff08\u5185\u6838\u6001\uff09\u3002\u5176\u4e2dfdatasync\u5c31\u662f\u4e00\u4e2a\u7cfb\u7edf\u8c03\u7528\uff0c\u8be5\u7cfb\u7edf\u8c03\u7528\u53ef\u4ee5\u901a\u77e5OS\u7acb\u523b\u5c06OS Cache\u4e2d\u7684\u6570\u636eFlush\u5230\u78c1\u76d8\u6587\u4ef6\u4e2d\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u9644\u5f552\uff1a\u6587\u4ef6\u63cf\u8ff0\u7b26\u4e0e\u6587\u4ef6\u64cd\u4f5c<\/h4>\n\n\n\n<p>\u8fd9\u65f6\u5019\u5185\u6838\u4f1a\u4e3a\u8be5\u8fdb\u7a0b\u6253\u5f00\u7684\u6587\u4ef6\u5206\u914d\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u5e76\u5c06\u8be5\u6587\u4ef6\u63cf\u8ff0\u7b26\u8fd4\u56de\u7ed9\u8be5\u8fdb\u7a0b\u3002\u5728\u5185\u6838\u7684\u6587\u4ef6\u8868\u4e2d\u65b0\u5efa\u4e00\u4e2a\u6587\u4ef6\u9879\uff0c\u6807\u8bb0\u6587\u4ef6\u72b6\u6001\u3001\u6587\u4ef6\u5f53\u524d\u504f\u79fb\u3001\u4ee5\u53caI\u8282\u70b9\uff08v\u8282\u70b9\uff09\u7684\u4f4d\u7f6e\uff0c\u5185\u6838\u8fd8\u4f1a\u6253\u5f00\u8be5\u6587\u4ef6\u7684I\u8282\u70b9\uff08\u8fd9\u91cc\u8bb0\u5f55\u6587\u4ef6\u7684\u64cd\u4f5c\u7684\u51fd\u6570\u6307\u9488\uff0c\u4f8b\u5982\u8bfb\u64cd\u4f5c\u3001\u5199\u64cd\u4f5c\uff09\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u9644\u5f553\uff1a\u5173\u4e8eO_RSYNC<\/h4>\n\n\n\n<p>\u3010\u9644\u5f553\u3011O_RSYNC\u6211\u7684\u7406\u89e3\u662f\uff0c\u5bf9\u4e8e\u540c\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u53ef\u4ee5\u4fdd\u8bc1\u8bfb\u6570\u636e\u5b89\u5168\u3002\u540c\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u5305\u62ecdup\u548cfcntl\u51fd\u6570dup\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u5373\u5171\u7528\u540c\u4e00\u4e2a\u6587\u4ef6\u8868\u9879\u3002O_RSYNC\u4e0d\u662f\u6211\u4eec\u4eca\u5929\u5173\u6ce8\u7684\uff0c\u6682\u65f6\u5ffd\u7565\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u9644\u5f554\uff1a\u5176\u4ed6\u6682\u672a\u786e\u8ba4\u7684\u95ee\u9898<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li>O_DIRECT\u5728\u54ea\u4e9bOS(\u6216\u8005FS)\u4e0a\u80fd\u591f\u6b63\u5e38\u5de5\u4f5c\uff1f<\/li>\n\n\n\n<li>O_SYNC\u5728\u54ea\u5199OS\u4e0a\u4e0d\u80fd\u6b63\u5e38\u5de5\u4f5c\u5462\uff1f<\/li>\n\n\n\n<li>\u5185\u6838\u7684read\u3001write\u662fFS\u7ea7\u522b\u7684\u8fd8\u662f\u5185\u6838(kernel)\u7ea7\u522b\uff1f<\/li>\n\n\n\n<li>\u6587\u7ae0<a href=\"http:\/\/rdc.taobao.com\/blog\/dba\/html\/296_innodb_flush_method_performance.html\">innodb_flush_method\u5e26\u6765\u7684\u6027\u80fd\u5f71\u54cd<\/a>\u4e2dO_DSYNC\u3001\u548cfdatasync\u6548\u7387\u5dee\u5f88\u591a\uff0c\u8fd9\u662f\u4e3a\u4ec0\u4e48\uff1f<\/li>\n<\/ol>\n\n\n\n<p>(\u5168\u6587\u5b8c)<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u9676\u65b9\u5728\u300ainnodb_flush_method\u5e26\u6765\u7684\u6027\u80fd\u5f71\u54cd\u300b\u4e2d\u4ece\u5b9e\u9a8c\u89d2\u5ea6\u6bd4\u8f83\u4e86fdatasync\uff0cO_DSYNC\u548cO_DIRECT\u5728\u6027\u80fd\u4e0a\u7684\u5dee\u5f02\u3002\u672c\u6587\u5c06\u8bd5\u56fe\u4eceLinux\/Unix&#8221;\u6587\u4ef6I\/O&#8221;\uff08unbuffered I\/O\uff09\u7684\u89d2\u5ea6\u6765\u89e3\u91cainnodb_flush_method\u662f\u5982\u4f55\u5f71\u54cdMySQL\u7684I\/O\u3002\u3010\u9644\u5f551\u3011 innodb_flush_log_at_trx_commit \u53c2\u6570\u786e\u5b9a\u65e5\u5fd7\u6587\u4ef6 \u4f55\u65f6 write\u3001flush\u3002innodb_flush_method\u5219\u786e\u5b9a\u65e5\u5fd7\u53ca\u6570\u636e\u6587\u4ef6 \u5982\u4f55 write\u3001flush\u3002\u5728Linux\u4e0b\uff0cinnodb_flush_method \u53ef\u4ee5\u53d6\u5982\u4e0b\u503c\uff1afdatasync, O_DSYNC, O_DIRECT\uff0c\u90a3\u8fd9\u4e09\u4e2a\u503c\u5206\u522b\u662f\u5982\u4f55\u5f71\u54cd\u6587\u4ef6\u5199\u5165\u7684\uff1f\u9996\u5148\u6211\u4eec\u9700\u8981\u5148\u6765\u4e86\u89e3Linux\u7684\u6587\u4ef6I\/O\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u3002<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","inline_featured_image":false,"_tocer_settings":[],"footnotes":""},"categories":[4],"tags":[28,121],"class_list":["post-693","post","type-post","status-publish","format-standard","hentry","category-code-detail","tag-file-io","tag-linux"],"_links":{"self":[{"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/posts\/693","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/comments?post=693"}],"version-history":[{"count":20,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/posts\/693\/revisions"}],"predecessor-version":[{"id":17690,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/posts\/693\/revisions\/17690"}],"wp:attachment":[{"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/media?parent=693"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/categories?post=693"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.orczhou.com\/index.php\/wp-json\/wp\/v2\/tags?post=693"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}