{"id":479420,"date":"2023-08-09T10:39:54","date_gmt":"2023-08-09T10:39:54","guid":{"rendered":""},"modified":"2023-09-05T11:18:47","modified_gmt":"2023-09-05T11:18:47","slug":"two-phase-commit","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/two-phase-commit\/","title":{"rendered":"Cam k\u1ebft hai pha"},"content":{"rendered":"<p>Cam k\u1ebft hai pha (2PC) l\u00e0 m\u1ed9t thu\u1eadt to\u00e1n ph\u00e2n t\u00e1n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong khoa h\u1ecdc m\u00e1y t\u00ednh \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o t\u00ednh nh\u1ea5t qu\u00e1n c\u1ee7a giao d\u1ecbch tr\u00ean nhi\u1ec1u c\u01a1 s\u1edf d\u1eef li\u1ec7u ho\u1eb7c t\u00e0i nguy\u00ean. N\u00f3 \u0111\u1ea3m b\u1ea3o r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c n\u00fat tham gia cam k\u1ebft th\u1ef1c hi\u1ec7n giao d\u1ecbch ho\u1eb7c kh\u00f4ng n\u00fat n\u00e0o th\u1ef1c hi\u1ec7n, do \u0111\u00f3 duy tr\u00ec t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 ng\u0103n ch\u1eb7n s\u1ef1 kh\u00f4ng nh\u1ea5t qu\u00e1n trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n.<\/p>\n<h2>L\u1ecbch s\u1eed ngu\u1ed3n g\u1ed1c c\u1ee7a cam k\u1ebft hai giai \u0111o\u1ea1n v\u00e0 s\u1ef1 \u0111\u1ec1 c\u1eadp \u0111\u1ea7u ti\u00ean v\u1ec1 n\u00f3<\/h2>\n<p>Kh\u00e1i ni\u1ec7m cam k\u1ebft hai giai \u0111o\u1ea1n \u0111\u01b0\u1ee3c EW Dijkstra gi\u1edbi thi\u1ec7u l\u1ea7n \u0111\u1ea7u ti\u00ean v\u00e0o n\u0103m 1974 trong b\u00e0i b\u00e1o c\u1ee7a \u00f4ng c\u00f3 t\u1ef1a \u0111\u1ec1 \u201cGi\u1ea3i ph\u00e1p cho m\u1ed9t v\u1ea5n \u0111\u1ec1 trong \u0110i\u1ec1u khi\u1ec3n l\u1eadp tr\u00ecnh \u0111\u1ed3ng th\u1eddi\u201d. Sau \u0111\u00f3, v\u00e0o n\u0103m 1981, giao th\u1ee9c cam k\u1ebft hai giai \u0111o\u1ea1n \u0111\u00e3 \u0111\u01b0\u1ee3c Jim Gray v\u00e0 Andreas Reuter m\u00f4 t\u1ea3 ch\u00ednh th\u1ee9c trong b\u00e0i b\u00e1o c\u00f3 \u1ea3nh h\u01b0\u1edfng l\u1edbn c\u1ee7a h\u1ecd \u201cX\u1eed l\u00fd giao d\u1ecbch: Kh\u00e1i ni\u1ec7m v\u00e0 K\u1ef9 thu\u1eadt\u201d.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 cam k\u1ebft hai giai \u0111o\u1ea1n<\/h2>\n<p>Cam k\u1ebft hai pha \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 qu\u1ea3n l\u00fd c\u00e1c giao d\u1ecbch ph\u00e2n t\u00e1n c\u00f3 li\u00ean quan \u0111\u1ebfn nhi\u1ec1u n\u00fat ho\u1eb7c c\u01a1 s\u1edf d\u1eef li\u1ec7u. \u0110i\u1ec1u c\u1ea7n thi\u1ebft l\u00e0 ph\u1ea3i \u0111\u1ea3m b\u1ea3o r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c n\u00fat \u0111\u1ec1u \u0111\u1ed3ng \u00fd v\u1ec1 vi\u1ec7c n\u00ean cam k\u1ebft hay h\u1ee7y b\u1ecf giao d\u1ecbch. Giao th\u1ee9c ho\u1ea1t \u0111\u1ed9ng theo hai giai \u0111o\u1ea1n: giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb v\u00e0 giai \u0111o\u1ea1n cam k\u1ebft.<\/p>\n<p>Trong giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb:<\/p>\n<ol>\n<li>N\u00fat \u0111i\u1ec1u ph\u1ed1i g\u1eedi y\u00eau c\u1ea7u chu\u1ea9n b\u1ecb t\u1edbi t\u1ea5t c\u1ea3 c\u00e1c n\u00fat tham gia.<\/li>\n<li>M\u1ed7i ng\u01b0\u1eddi tham gia tr\u1ea3 l\u1eddi \u0111\u1ed3ng \u00fd (C\u00d3) ho\u1eb7c kh\u00f4ng \u0111\u1ed3ng \u00fd (KH\u00d4NG).<\/li>\n<li>N\u1ebfu b\u1ea5t k\u1ef3 ng\u01b0\u1eddi tham gia n\u00e0o kh\u00f4ng \u0111\u1ed3ng \u00fd, \u0111i\u1ec1u ph\u1ed1i vi\u00ean s\u1ebd h\u01b0\u1edbng d\u1eabn t\u1ea5t c\u1ea3 c\u00e1c n\u00fat h\u1ee7y b\u1ecf giao d\u1ecbch.<\/li>\n<\/ol>\n<p>Trong giai \u0111o\u1ea1n cam k\u1ebft:<\/p>\n<ol>\n<li>N\u1ebfu t\u1ea5t c\u1ea3 nh\u1eefng ng\u01b0\u1eddi tham gia \u0111\u1ed3ng \u00fd (C\u00d3) trong giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb, \u0111i\u1ec1u ph\u1ed1i vi\u00ean s\u1ebd g\u1eedi y\u00eau c\u1ea7u cam k\u1ebft \u0111\u1ebfn t\u1ea5t c\u1ea3 c\u00e1c n\u00fat.<\/li>\n<li>Khi nh\u1eadn \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u cam k\u1ebft, m\u1ed7i ng\u01b0\u1eddi tham gia s\u1ebd ho\u00e0n t\u1ea5t giao d\u1ecbch b\u1eb1ng c\u00e1ch th\u1ef1c hi\u1ec7n v\u0129nh vi\u1ec5n nh\u1eefng thay \u0111\u1ed5i c\u1ea7n thi\u1ebft.<\/li>\n<li>N\u1ebfu b\u1ea5t k\u1ef3 ng\u01b0\u1eddi tham gia n\u00e0o kh\u00f4ng \u0111\u1ed3ng \u00fd (NO) trong giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb, \u0111i\u1ec1u ph\u1ed1i vi\u00ean s\u1ebd g\u1eedi y\u00eau c\u1ea7u h\u1ee7y b\u1ecf \u0111\u1ebfn t\u1ea5t c\u1ea3 c\u00e1c n\u00fat v\u00e0 giao d\u1ecbch s\u1ebd \u0111\u01b0\u1ee3c kh\u00f4i ph\u1ee5c.<\/li>\n<\/ol>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a cam k\u1ebft hai giai \u0111o\u1ea1n v\u00e0 c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng<\/h2>\n<p>Cam k\u1ebft hai giai \u0111o\u1ea1n bao g\u1ed3m c\u00e1c th\u00e0nh ph\u1ea7n sau:<\/p>\n<ol>\n<li>\n<p><strong>\u0110i\u1ec1u ph\u1ed1i vi\u00ean<\/strong>: Ch\u1ecbu tr\u00e1ch nhi\u1ec7m kh\u1edfi t\u1ea1o v\u00e0 qu\u1ea3n l\u00fd giao d\u1ecbch. N\u00f3 li\u00ean l\u1ea1c v\u1edbi t\u1ea5t c\u1ea3 c\u00e1c n\u00fat tham gia v\u00e0 x\u00e1c \u0111\u1ecbnh xem n\u00ean th\u1ef1c hi\u1ec7n hay h\u1ee7y b\u1ecf giao d\u1ecbch d\u1ef1a tr\u00ean ph\u1ea3n h\u1ed3i c\u1ee7a ch\u00fang.<\/p>\n<\/li>\n<li>\n<p><strong>Nh\u1eefng ng\u01b0\u1eddi tham gia<\/strong>: C\u00e1c n\u00fat ho\u1eb7c c\u01a1 s\u1edf d\u1eef li\u1ec7u li\u00ean quan \u0111\u1ebfn giao d\u1ecbch. H\u1ecd \u0111\u00e1p l\u1ea1i y\u00eau c\u1ea7u chu\u1ea9n b\u1ecb c\u1ee7a \u0111i\u1ec1u ph\u1ed1i vi\u00ean b\u1eb1ng s\u1ef1 \u0111\u1ed3ng \u00fd ho\u1eb7c kh\u00f4ng \u0111\u1ed3ng \u00fd.<\/p>\n<\/li>\n<li>\n<p><strong>Nh\u1eadt k\u00fd giao d\u1ecbch<\/strong>: M\u1ed7i ng\u01b0\u1eddi tham gia duy tr\u00ec nh\u1eadt k\u00fd giao d\u1ecbch, ghi l\u1ea1i t\u1ea5t c\u1ea3 c\u00e1c thay \u0111\u1ed5i \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n trong qu\u00e1 tr\u00ecnh giao d\u1ecbch. Nh\u1eadt k\u00fd n\u00e0y gi\u00fap \u0111\u1ea3m b\u1ea3o r\u1eb1ng nh\u1eefng thay \u0111\u1ed5i c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c kh\u00f4i ph\u1ee5c n\u1ebfu c\u1ea7n thi\u1ebft.<\/p>\n<\/li>\n<\/ol>\n<p>C\u00e1c thu\u1eadt to\u00e1n ti\u1ebfn h\u00e0nh nh\u01b0 sau:<\/p>\n<ol>\n<li>\n<p>\u0110i\u1ec1u ph\u1ed1i vi\u00ean b\u1eaft \u0111\u1ea7u giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb b\u1eb1ng c\u00e1ch g\u1eedi y\u00eau c\u1ea7u chu\u1ea9n b\u1ecb cho t\u1ea5t c\u1ea3 ng\u01b0\u1eddi tham gia.<\/p>\n<\/li>\n<li>\n<p>M\u1ed7i ng\u01b0\u1eddi tham gia b\u1ecf phi\u1ebfu (\u0111\u1ed3ng \u00fd ho\u1eb7c kh\u00f4ng \u0111\u1ed3ng \u00fd) v\u1ec1 vi\u1ec7c li\u1ec7u h\u1ecd c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n giao d\u1ecbch hay kh\u00f4ng.<\/p>\n<\/li>\n<li>\n<p>\u0110i\u1ec1u ph\u1ed1i vi\u00ean thu th\u1eadp t\u1ea5t c\u1ea3 c\u00e1c phi\u1ebfu b\u1ea7u v\u00e0 quy\u1ebft \u0111\u1ecbnh th\u1ef1c hi\u1ec7n hay h\u1ee7y b\u1ecf giao d\u1ecbch.<\/p>\n<\/li>\n<li>\n<p>Trong giai \u0111o\u1ea1n cam k\u1ebft, \u0111i\u1ec1u ph\u1ed1i vi\u00ean s\u1ebd g\u1eedi y\u00eau c\u1ea7u cam k\u1ebft ho\u1eb7c h\u1ee7y b\u1ecf t\u1edbi t\u1ea5t c\u1ea3 nh\u1eefng ng\u01b0\u1eddi tham gia d\u1ef1a tr\u00ean k\u1ebft qu\u1ea3 c\u1ee7a giai \u0111o\u1ea1n chu\u1ea9n b\u1ecb.<\/p>\n<\/li>\n<li>\n<p>Nh\u1eefng ng\u01b0\u1eddi tham gia th\u1ef1c hi\u1ec7n quy\u1ebft \u0111\u1ecbnh cu\u1ed1i c\u00f9ng, cam k\u1ebft thay \u0111\u1ed5i v\u0129nh vi\u1ec5n ho\u1eb7c kh\u00f4i ph\u1ee5c giao d\u1ecbch.<\/p>\n<\/li>\n<\/ol>\n<h2>Ph\u00e2n t\u00edch c\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a cam k\u1ebft hai giai \u0111o\u1ea1n<\/h2>\n<p>Cam k\u1ebft hai giai \u0111o\u1ea1n cung c\u1ea5p m\u1ed9t s\u1ed1 t\u00ednh n\u0103ng ch\u00ednh:<\/p>\n<ol>\n<li>\n<p><strong>T\u00ednh nguy\u00ean t\u1eed<\/strong>: N\u00f3 \u0111\u1ea3m b\u1ea3o r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c n\u00fat cam k\u1ebft ho\u1eb7c kh\u00f4ng n\u00fat n\u00e0o th\u1ef1c hi\u1ec7n, tr\u00e1nh c\u1eadp nh\u1eadt m\u1ed9t ph\u1ea7n ho\u1eb7c kh\u00f4ng nh\u1ea5t qu\u00e1n.<\/p>\n<\/li>\n<li>\n<p><strong>T\u00ednh nh\u1ea5t qu\u00e1n<\/strong>: Giao th\u1ee9c \u0111\u1ea3m b\u1ea3o r\u1eb1ng h\u1ec7 th\u1ed1ng v\u1eabn nh\u1ea5t qu\u00e1n, ngay c\u1ea3 khi c\u00f3 l\u1ed7i.<\/p>\n<\/li>\n<li>\n<p><strong>\u0110\u1ed9 b\u1ec1n<\/strong>: Sau khi giao d\u1ecbch \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n, c\u00e1c thay \u0111\u1ed5i s\u1ebd tr\u1edf th\u00e0nh v\u0129nh vi\u1ec5n v\u00e0 t\u1ed3n t\u1ea1i sau c\u00e1c l\u1ed7i h\u1ec7 th\u1ed1ng.<\/p>\n<\/li>\n<li>\n<p><strong>Ch\u1eb7n thi\u00ean nhi\u00ean<\/strong>: Cam k\u1ebft hai giai \u0111o\u1ea1n c\u00f3 t\u00ednh ch\u1ea5t ch\u1eb7n, ngh\u0129a l\u00e0 n\u00f3 c\u00f3 th\u1ec3 ch\u1edd v\u00f4 th\u1eddi h\u1ea1n \u0111\u1ec3 nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ea3n h\u1ed3i t\u1eeb nh\u1eefng ng\u01b0\u1eddi tham gia, d\u1eabn \u0111\u1ebfn kh\u1ea3 n\u0103ng ch\u1eadm tr\u1ec5.<\/p>\n<\/li>\n<\/ol>\n<h2>C\u00e1c lo\u1ea1i cam k\u1ebft hai pha<\/h2>\n<p>C\u00f3 c\u00e1c bi\u1ebfn th\u1ec3 c\u1ee7a giao th\u1ee9c cam k\u1ebft hai giai \u0111o\u1ea1n, bao g\u1ed3m:<\/p>\n<table>\n<thead>\n<tr>\n<th>Ki\u1ec3u<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Cam k\u1ebft hai pha c\u01a1 b\u1ea3n<\/td>\n<td>Phi\u00ean b\u1ea3n ti\u00eau chu\u1ea9n \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 tr\u01b0\u1edbc \u0111\u00f3.<\/td>\n<\/tr>\n<tr>\n<td>Cam k\u1ebft ba pha<\/td>\n<td>Th\u00eam giai \u0111o\u1ea1n &quot;cam k\u1ebft tr\u01b0\u1edbc&quot; b\u1ed5 sung \u0111\u1ec3 gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 ch\u1eb7n.<\/td>\n<\/tr>\n<tr>\n<td>Cam k\u1ebft l\u1ea1c quan<\/td>\n<td>Cho ph\u00e9p ng\u01b0\u1eddi tham gia cam k\u1ebft tr\u01b0\u1edbc khi nh\u1eadn quy\u1ebft \u0111\u1ecbnh t\u1eeb \u0111i\u1ec1u ph\u1ed1i vi\u00ean.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng Cam k\u1ebft hai giai \u0111o\u1ea1n, V\u1ea5n \u0111\u1ec1 v\u00e0 Gi\u1ea3i ph\u00e1p c\u1ee7a ch\u00fang<\/h2>\n<p>Cam k\u1ebft hai giai \u0111o\u1ea1n t\u00ecm th\u1ea5y c\u00e1c \u1ee9ng d\u1ee5ng trong c\u00e1c l\u0129nh v\u1ef1c kh\u00e1c nhau, ch\u1eb3ng h\u1ea1n nh\u01b0:<\/p>\n<ol>\n<li>\n<p><strong>Qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u<\/strong>: \u0110\u1ea3m b\u1ea3o t\u00ednh nh\u1ea5t qu\u00e1n v\u00e0 to\u00e0n v\u1eb9n trong h\u1ec7 th\u1ed1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u ph\u00e2n t\u00e1n.<\/p>\n<\/li>\n<li>\n<p><strong>Giao d\u1ecbch th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed<\/strong>: Qu\u1ea3n l\u00fd giao d\u1ecbch tr\u00ean nhi\u1ec1u m\u00e1y ch\u1ee7 trong qu\u00e1 tr\u00ecnh mua h\u00e0ng tr\u1ef1c tuy\u1ebfn.<\/p>\n<\/li>\n<\/ol>\n<p>Tuy nhi\u00ean, giao th\u1ee9c c\u00f3 m\u1ed9t s\u1ed1 h\u1ea1n ch\u1ebf:<\/p>\n<ol>\n<li>\n<p><strong>Ch\u1eb7n<\/strong>: T\u00ednh ch\u1ea5t ch\u1eb7n c\u1ee7a 2PC c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn c\u00e1c v\u1ea5n \u0111\u1ec1 v\u1ec1 hi\u1ec7u su\u1ea5t, \u0111\u1eb7c bi\u1ec7t l\u00e0 trong c\u00e1c h\u1ec7 th\u1ed1ng quy m\u00f4 l\u1edbn.<\/p>\n<\/li>\n<li>\n<p><strong>\u0110i\u1ec3m th\u1ea5t b\u1ea1i duy nh\u1ea5t<\/strong>: \u0110i\u1ec1u ph\u1ed1i vi\u00ean ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t \u0111i\u1ec3m l\u1ed7i duy nh\u1ea5t; n\u1ebfu n\u00f3 g\u1eb7p s\u1ef1 c\u1ed1, to\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh giao d\u1ecbch c\u00f3 th\u1ec3 th\u1ea5t b\u1ea1i.<\/p>\n<\/li>\n<\/ol>\n<p>\u0110\u1ec3 gi\u1ea3m thi\u1ec3u nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y, m\u1ed9t s\u1ed1 gi\u1ea3i ph\u00e1p bao g\u1ed3m:<\/p>\n<ol>\n<li>\n<p><strong>T\u1ed1i \u01b0u h\u00f3a<\/strong>: Tri\u1ec3n khai c\u00e1c k\u1ef9 thu\u1eadt t\u1ed1i \u01b0u h\u00f3a, ch\u1eb3ng h\u1ea1n nh\u01b0 chi\u1ebfn l\u01b0\u1ee3c cam k\u1ebft h\u00e1o h\u1ee9c ho\u1eb7c chi\u1ebfn l\u01b0\u1ee3c cam k\u1ebft kh\u00f4ng ch\u1eb7n, \u0111\u1ec3 gi\u1ea3m thi\u1ec3u c\u00e1c v\u1ea5n \u0111\u1ec1 ch\u1eb7n.<\/p>\n<\/li>\n<li>\n<p><strong>\u0110i\u1ec1u ph\u1ed1i vi\u00ean d\u1ef1 ph\u00f2ng<\/strong>: Gi\u1edbi thi\u1ec7u c\u01a1 ch\u1ebf d\u1ef1 ph\u00f2ng \u0111i\u1ec1u ph\u1ed1i vi\u00ean v\u1edbi c\u01a1 ch\u1ebf chuy\u1ec3n \u0111\u1ed5i d\u1ef1 ph\u00f2ng \u0111\u1ec3 c\u1ea3i thi\u1ec7n kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ed7i.<\/p>\n<\/li>\n<\/ol>\n<h2>C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m ch\u00ednh v\u00e0 nh\u1eefng so s\u00e1nh kh\u00e1c v\u1edbi c\u00e1c thu\u1eadt ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u0111\u1eb7c tr\u01b0ng<\/th>\n<th>So s\u00e1nh v\u1edbi cam k\u1ebft hai pha<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>T\u00ednh nh\u1ea5t qu\u00e1n<\/td>\n<td>T\u01b0\u01a1ng t\u1ef1 nh\u01b0 Cam k\u1ebft ba pha v\u00e0 Paxos trong vi\u1ec7c duy tr\u00ec t\u00ednh nh\u1ea5t qu\u00e1n trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n.<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u su\u1ea5t<\/td>\n<td>So v\u1edbi Paxos v\u00e0 Raft, Cam k\u1ebft hai pha c\u00f3 th\u1ec3 c\u00f3 \u0111\u1ed9 tr\u1ec5 cao h\u01a1n do b\u1ecb ch\u1eb7n.<\/td>\n<\/tr>\n<tr>\n<td>Dung sai l\u1ed7i<\/td>\n<td>Cam k\u1ebft hai pha v\u00e0 Paxos \u0111\u1ec1u cung c\u1ea5p kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ed7i, trong khi Cam k\u1ebft hai pha th\u1ef1c hi\u1ec7n \u0111\u01a1n gi\u1ea3n h\u01a1n.<\/td>\n<\/tr>\n<tr>\n<td>Chi ph\u00ed li\u00ean l\u1ea1c<\/td>\n<td>Raft c\u00f3 chi ph\u00ed li\u00ean l\u1ea1c th\u1ea5p h\u01a1n so v\u1edbi Cam k\u1ebft hai pha, khi\u1ebfn n\u00f3 ph\u00f9 h\u1ee3p h\u01a1n v\u1edbi c\u00e1c h\u1ec7 th\u1ed1ng quy m\u00f4 l\u1edbn.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m v\u00e0 c\u00f4ng ngh\u1ec7 c\u1ee7a t\u01b0\u01a1ng lai li\u00ean quan \u0111\u1ebfn cam k\u1ebft hai giai \u0111o\u1ea1n<\/h2>\n<p>Khi c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n ti\u1ebfp t\u1ee5c ph\u00e1t tri\u1ec3n, c\u00e1c giao th\u1ee9c giao d\u1ecbch c\u00f3 kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ed7i v\u00e0 hi\u1ec7u qu\u1ea3 h\u01a1n c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n. C\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u \u0111ang kh\u00e1m ph\u00e1 c\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf nh\u01b0 Raft, Paxos v\u00e0 c\u00e1c bi\u1ebfn th\u1ec3 c\u1ee7a Cam k\u1ebft hai giai \u0111o\u1ea1n \u0111\u1ec3 gi\u1ea3i quy\u1ebft c\u00e1c h\u1ea1n ch\u1ebf v\u00e0 v\u1ea5n \u0111\u1ec1 v\u1ec1 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng. Ngo\u00e0i ra, nh\u1eefng ti\u1ebfn b\u1ed9 trong thu\u1eadt to\u00e1n \u0111\u1ed3ng thu\u1eadn v\u00e0 h\u1ecdc m\u00e1y c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn nh\u1eefng c\u00e1ch m\u1edbi \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c th\u1ecfa thu\u1eadn ph\u00e2n t\u00e1n.<\/p>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng ho\u1eb7c li\u00ean k\u1ebft m\u00e1y ch\u1ee7 proxy v\u1edbi cam k\u1ebft hai giai \u0111o\u1ea1n<\/h2>\n<p>M\u00e1y ch\u1ee7 proxy \u0111\u00f3ng vai tr\u00f2 trung gian gi\u1eefa m\u00e1y kh\u00e1ch v\u00e0 m\u00e1y ch\u1ee7, thay m\u1eb7t m\u00e1y kh\u00e1ch x\u1eed l\u00fd c\u00e1c y\u00eau c\u1ea7u v\u00e0 ph\u1ea3n h\u1ed3i. M\u1eb7c d\u00f9 kh\u00f4ng li\u00ean k\u1ebft tr\u1ef1c ti\u1ebfp v\u1edbi Cam k\u1ebft hai pha, nh\u01b0ng m\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 \u0111\u00f3ng m\u1ed9t vai tr\u00f2 quan tr\u1ecdng trong vi\u1ec7c ph\u00e2n ph\u1ed1i giao d\u1ecbch tr\u00ean nhi\u1ec1u m\u00e1y ch\u1ee7 ph\u1ee5 tr\u1ee3.<\/p>\n<p>Khi kh\u00e1ch h\u00e0ng b\u1eaft \u0111\u1ea7u c\u00e1c giao d\u1ecbch ph\u00e2n t\u00e1n th\u00f4ng qua m\u00e1y ch\u1ee7 proxy, proxy c\u00f3 th\u1ec3 \u0111\u1ecbnh tuy\u1ebfn c\u00e1c y\u00eau c\u1ea7u m\u1ed9t c\u00e1ch th\u00f4ng minh \u0111\u1ebfn c\u00e1c n\u00fat ph\u1ee5 tr\u1ee3 kh\u00e1c nhau, tham gia v\u00e0o giao th\u1ee9c cam k\u1ebft hai pha. \u0110i\u1ec1u n\u00e0y cho ph\u00e9p c\u00e2n b\u1eb1ng t\u1ea3i v\u00e0 n\u00e2ng cao kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ed7i trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n. H\u01a1n n\u1eefa, m\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 l\u01b0u v\u00e0o b\u1ed9 nh\u1edb \u0111\u1ec7m c\u00e1c ph\u1ea3n h\u1ed3i, gi\u1ea3m t\u1ea3i cho c\u00e1c n\u00fat ph\u1ee5 tr\u1ee3 v\u00e0 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t t\u1ed5ng th\u1ec3 c\u1ee7a h\u1ec7 th\u1ed1ng.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.microsoft.com\/en-us\/research\/publication\/distributed-transactions-two-phase-commit-protocol\/\" target=\"_new\" rel=\"noopener nofollow\">Giao d\u1ecbch ph\u00e2n t\u00e1n: Giao th\u1ee9c cam k\u1ebft hai pha<\/a><\/li>\n<li><a href=\"https:\/\/dzone.com\/articles\/a-guide-to-the-two-phase-commit-protocol\" target=\"_new\" rel=\"noopener nofollow\">H\u01b0\u1edbng d\u1eabn v\u1ec1 Giao th\u1ee9c cam k\u1ebft hai pha<\/a><\/li>\n<li><a href=\"https:\/\/www.infoq.com\/presentations\/paxos-distributed-consensus-protocols\/\" target=\"_new\" rel=\"noopener nofollow\">Giao th\u1ee9c \u0111\u1ed3ng thu\u1eadn: Cam k\u1ebft hai giai \u0111o\u1ea1n so v\u1edbi Paxos<\/a><\/li>\n<li><a href=\"https:\/\/raft.github.io\/\" target=\"_new\" rel=\"noopener nofollow\">Hi\u1ec3u thu\u1eadt to\u00e1n \u0111\u1ed3ng thu\u1eadn Raft<\/a><\/li>\n<li><a href=\"https:\/\/lamport.azurewebsites.net\/pubs\/paxos-simple.pdf\" target=\"_new\" rel=\"noopener nofollow\">Paxos \u0111\u01a1n gi\u1ea3n<\/a><\/li>\n<\/ul>\n<p>T\u00f3m l\u1ea1i, Cam k\u1ebft hai pha l\u00e0 m\u1ed9t thu\u1eadt to\u00e1n ph\u00e2n t\u00e1n quan tr\u1ecdng \u0111\u1ec3 duy tr\u00ec t\u00ednh nh\u1ea5t qu\u00e1n giao d\u1ecbch tr\u00ean nhi\u1ec1u n\u00fat. B\u1ea5t ch\u1ea5p t\u00ednh ch\u1ea5t ch\u1eb7n v\u00e0 l\u1ed7 h\u1ed5ng \u0111i\u1ec1u ph\u1ed1i vi\u00ean, n\u00f3 v\u1eabn \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong nhi\u1ec1u \u1ee9ng d\u1ee5ng kh\u00e1c nhau. Khi c\u00f4ng ngh\u1ec7 ph\u00e1t tri\u1ec3n, c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u ti\u1ebfp t\u1ee5c kh\u00e1m ph\u00e1 c\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf v\u00e0 t\u1ed1i \u01b0u h\u00f3a, \u0111\u1ed3ng th\u1eddi c\u00e1c m\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 n\u00e2ng cao hi\u1ec7u qu\u1ea3 c\u1ee7a n\u00f3 trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n. Hi\u1ec3u c\u00e1c s\u1eafc th\u00e1i c\u1ee7a giao th\u1ee9c cam k\u1ebft hai pha l\u00e0 \u0111i\u1ec1u c\u1ea7n thi\u1ebft \u0111\u1ec3 x\u00e2y d\u1ef1ng c\u00e1c \u1ee9ng d\u1ee5ng ph\u00e2n t\u00e1n m\u1ea1nh m\u1ebd v\u00e0 \u0111\u00e1ng tin c\u1eady.<\/p>","protected":false},"featured_media":479421,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-479420","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Two-phase commit: A Comprehensive Overview<\/mark>","faq_items":[{"question":"What is Two-phase commit?","answer":"<p>Two-phase commit (2PC) is a distributed algorithm used in computer science to ensure the consistency of a transaction across multiple databases or resources. It guarantees that either all participating nodes commit to the transaction or none of them do, thereby maintaining data integrity and preventing inconsistencies in distributed systems.<\/p>"},{"question":"Who first introduced the concept of Two-phase commit?","answer":"<p>The concept of Two-phase commit was first introduced by E. W. Dijkstra in 1974 in his paper titled \"Solution of a Problem in Concurrent Programming Control.\" Later, in 1981, Jim Gray and Andreas Reuter formally described the Two-phase commit protocol in their paper \"Transaction Processing: Concepts and Techniques.\"<\/p>"},{"question":"How does Two-phase commit work?","answer":"<p>Two-phase commit operates in two phases: the preparation phase and the commit phase. In the preparation phase, the coordinator node sends a prepare request to all participating nodes, and each participant replies with an agreement (YES) or disagreement (NO). If any participant disagrees, the coordinator instructs all nodes to abort the transaction. In the commit phase, if all participants agreed during the preparation phase, the coordinator sends a commit request to all nodes. Each participant finalizes the transaction by making the necessary changes permanent. If any participant disagreed during the preparation phase, the coordinator sends an abort request to all nodes, and the transaction is rolled back.<\/p>"},{"question":"What are the key features of Two-phase commit?","answer":"<p>Two-phase commit offers several key features, including atomicity (ensuring all nodes commit or none do), consistency, durability, and a blocking nature (waiting for responses, potentially causing delays).<\/p>"},{"question":"Are there different types of Two-phase commit?","answer":"<p>Yes, variations of the Two-phase commit protocol exist. Some of them include:<\/p><ol><li>Basic Two-phase commit: The standard version described earlier.<\/li><li>Three-phase commit: Adds an extra \"pre-commit\" phase to address blocking issues.<\/li><li>Optimistic commit: Allows participants to pre-commit before receiving the decision from the coordinator.<\/li><\/ol>"},{"question":"In what applications is Two-phase commit used?","answer":"<p>Two-phase commit finds applications in various fields, including database management to ensure consistency and integrity in distributed databases, and e-commerce transactions for managing transactions across multiple servers during online purchases.<\/p>"},{"question":"What are the problems associated with Two-phase commit and their solutions?","answer":"<p>Two-phase commit has some limitations, such as its blocking nature and coordinator vulnerability. To mitigate these issues, optimization techniques like eager commit or non-blocking commit strategies can be employed. Additionally, introducing coordinator redundancy with a failover mechanism improves fault tolerance.<\/p>"},{"question":"How does Two-phase commit compare to other consensus protocols?","answer":"<p>Compared to other consensus protocols like Three-phase commit, Paxos, and Raft, Two-phase commit may exhibit higher latency due to blocking. While it provides fault tolerance and simplicity of implementation, alternatives like Raft and Paxos may offer lower communication overhead and better scalability.<\/p>"},{"question":"How does the future look for Two-phase commit?","answer":"<p>As distributed systems continue to evolve, researchers are exploring more efficient and fault-tolerant transaction protocols. Advancements in consensus algorithms and machine learning may lead to novel ways of achieving distributed agreement in the future.<\/p>"},{"question":"How are proxy servers associated with Two-phase commit?","answer":"<p>Proxy servers can play a significant role in distributing transactions across multiple backend servers. They can intelligently route requests to different backend nodes participating in the Two-phase commit protocol, ensuring load balancing and enhanced fault tolerance in distributed systems. Additionally, proxy servers can cache responses, reducing the load on backend nodes and improving overall system performance.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/479420","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/479420\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/479421"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=479420"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}