{"id":476326,"date":"2023-08-09T07:28:31","date_gmt":"2023-08-09T07:28:31","guid":{"rendered":""},"modified":"2023-09-05T11:12:28","modified_gmt":"2023-09-05T11:12:28","slug":"columnstore-indexes-in-sql","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/columnstore-indexes-in-sql\/","title":{"rendered":"Ch\u1ec9 m\u1ee5c kho c\u1ed9t trong SQL"},"content":{"rendered":"<h2>Gi\u1edbi thi\u1ec7u<\/h2>\n<p>Ch\u1ec9 m\u1ee5c Columnstore trong SQL l\u00e0 m\u1ed9t t\u00ednh n\u0103ng c\u01a1 s\u1edf d\u1eef li\u1ec7u chuy\u00ean bi\u1ec7t c\u00f3 th\u1ec3 c\u1ea3i thi\u1ec7n \u0111\u00e1ng k\u1ec3 hi\u1ec7u su\u1ea5t truy v\u1ea5n v\u00e0 n\u00e9n d\u1eef li\u1ec7u trong m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p nh\u1ea5t \u0111\u1ecbnh. Ch\u00fang \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 gi\u1ea3i quy\u1ebft c\u00e1c th\u00e1ch th\u1ee9c v\u1ec1 hi\u1ec7u su\u1ea5t v\u00e0 l\u01b0u tr\u1eef li\u00ean quan \u0111\u1ebfn vi\u1ec7c x\u1eed l\u00fd kh\u1ed1i l\u01b0\u1ee3ng l\u1edbn d\u1eef li\u1ec7u trong kh\u1ed1i l\u01b0\u1ee3ng c\u00f4ng vi\u1ec7c ph\u00e2n t\u00edch v\u00e0 l\u01b0u tr\u1eef d\u1eef li\u1ec7u. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd \u0111i s\u00e2u v\u00e0o l\u1ecbch s\u1eed, c\u1ea5u tr\u00fac b\u00ean trong, c\u00e1c t\u00ednh n\u0103ng ch\u00ednh, lo\u1ea1i, c\u00e1ch s\u1eed d\u1ee5ng v\u00e0 quan \u0111i\u1ec3m trong t\u01b0\u01a1ng lai c\u1ee7a c\u00e1c ch\u1ec9 m\u1ee5c Columnstore trong SQL.<\/p>\n<h2>L\u1ecbch s\u1eed v\u00e0 ngu\u1ed3n g\u1ed1c<\/h2>\n<p>C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore trong SQL \u0111\u01b0\u1ee3c Microsoft gi\u1edbi thi\u1ec7u l\u1ea7n \u0111\u1ea7u ti\u00ean khi ph\u00e1t h\u00e0nh SQL Server 2012. Kh\u00e1i ni\u1ec7m l\u01b0u tr\u1eef theo c\u1ed9t, l\u00e0m n\u1ec1n t\u1ea3ng cho c\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore, \u0111\u00e3 c\u00f3 t\u1eeb nh\u1eefng n\u0103m 1970. Tuy nhi\u00ean, n\u00f3 \u0111\u00e3 tr\u1edf n\u00ean ph\u1ed5 bi\u1ebfn v\u00e0o gi\u1eefa nh\u1eefng n\u0103m 2000 v\u1edbi s\u1ef1 gia t\u0103ng c\u1ee7a d\u1eef li\u1ec7u l\u1edbn v\u00e0 nhu c\u1ea7u v\u1ec1 hi\u1ec7u su\u1ea5t truy v\u1ea5n v\u00e0 n\u00e9n d\u1eef li\u1ec7u t\u1ed1t h\u01a1n. Vi\u1ec7c tri\u1ec3n khai c\u00e1c ch\u1ec9 m\u1ee5c Columnstore c\u1ee7a Microsoft \u0111\u00e3 \u0111\u00e1nh d\u1ea5u m\u1ed9t ti\u1ebfn b\u1ed9 \u0111\u00e1ng k\u1ec3 trong l\u0129nh v\u1ef1c n\u00e0y, khi\u1ebfn n\u00f3 tr\u1edf th\u00e0nh m\u1ed9t t\u00ednh n\u0103ng ti\u00eau chu\u1ea9n trong nhi\u1ec1u h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u hi\u1ec7n \u0111\u1ea1i.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 ch\u1ec9 m\u1ee5c Columnstore trong SQL<\/h2>\n<p>Ch\u1ec9 m\u1ee5c Columnstore l\u00e0 c\u00f4ng ngh\u1ec7 t\u1ed5 ch\u1ee9c v\u00e0 l\u01b0u tr\u1eef d\u1eef li\u1ec7u theo c\u1ed9t thay v\u00ec l\u01b0u tr\u1eef theo h\u00e0ng truy\u1ec1n th\u1ed1ng. Trong l\u01b0u tr\u1eef theo h\u00e0ng, d\u1eef li\u1ec7u trong b\u1ea3ng \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef v\u00e0 truy xu\u1ea5t theo t\u1eebng h\u00e0ng. Ng\u01b0\u1ee3c l\u1ea1i, v\u1edbi ch\u1ec9 m\u1ee5c Columnstore, d\u1eef li\u1ec7u trong m\u1ed7i c\u1ed9t \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef v\u00e0 x\u1eed l\u00fd c\u00f9ng nhau, d\u1eabn \u0111\u1ebfn kh\u1ea3 n\u0103ng n\u00e9n \u0111\u01b0\u1ee3c c\u1ea3i thi\u1ec7n v\u00e0 hi\u1ec7u su\u1ea5t t\u1ed1t h\u01a1n cho c\u00e1c truy v\u1ea5n ph\u00e2n t\u00edch.<\/p>\n<p>C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore r\u1ea5t ph\u00f9 h\u1ee3p cho kh\u1ed1i l\u01b0\u1ee3ng c\u00f4ng vi\u1ec7c c\u1ea7n \u0111\u1ecdc nhi\u1ec1u, trong \u0111\u00f3 c\u00e1c truy v\u1ea5n li\u00ean quan \u0111\u1ebfn l\u01b0\u1ee3ng l\u1edbn d\u1eef li\u1ec7u v\u00e0 t\u1eadp h\u1ee3p. Ch\u00fang c\u00f3 th\u1ec3 t\u0103ng t\u1ed1c \u0111\u00e1ng k\u1ec3 vi\u1ec7c b\u00e1o c\u00e1o, l\u01b0u tr\u1eef d\u1eef li\u1ec7u v\u00e0 truy v\u1ea5n ph\u00e2n t\u00edch y\u00eau c\u1ea7u qu\u00e9t v\u00e0 x\u1eed l\u00fd c\u00e1c t\u1eadp d\u1eef li\u1ec7u l\u1edbn.<\/p>\n<h2>C\u1ea5u tr\u00fac v\u00e0 ch\u1ee9c n\u0103ng b\u00ean trong<\/h2>\n<p>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a ch\u1ec9 m\u1ee5c Columnstore d\u1ef1a tr\u00ean c\u00e1c ph\u00e2n \u0111o\u1ea1n c\u1ed9t v\u00e0 t\u1eeb \u0111i\u1ec3n. Ph\u00e2n \u0111o\u1ea1n c\u1ed9t l\u00e0 \u0111\u01a1n v\u1ecb d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c n\u00e9n cho m\u1ed7i c\u1ed9t. N\u00f3 bao g\u1ed3m m\u1ed9t t\u1eadp h\u1ee3p c\u00e1c gi\u00e1 tr\u1ecb c\u00f9ng v\u1edbi m\u1ed9t lo\u1ea1t si\u00eau d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c gi\u00e1 tr\u1ecb t\u1ed1i thi\u1ec3u v\u00e0 t\u1ed1i \u0111a, \u0111\u1ec3 h\u1ed7 tr\u1ee3 vi\u1ec7c truy xu\u1ea5t d\u1eef li\u1ec7u.<\/p>\n<p>T\u1eeb \u0111i\u1ec3n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 n\u00e9n c\u00e1c gi\u00e1 tr\u1ecb l\u1eb7p l\u1ea1i trong m\u1ed9t c\u1ed9t. Thay v\u00ec l\u01b0u tr\u1eef c\u00e1c gi\u00e1 tr\u1ecb th\u1ef1c t\u1ebf nhi\u1ec1u l\u1ea7n, t\u1eeb \u0111i\u1ec3n l\u01b0u tr\u1eef c\u00e1c gi\u00e1 tr\u1ecb duy nh\u1ea5t v\u00e0 ID t\u01b0\u01a1ng \u1ee9ng c\u1ee7a ch\u00fang, gi\u1ea3m y\u00eau c\u1ea7u l\u01b0u tr\u1eef v\u00e0 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t truy v\u1ea5n.<\/p>\n<p>Ch\u1ec9 m\u1ee5c Columnstore t\u1eadn d\u1ee5ng m\u1ed9t k\u1ef9 thu\u1eadt g\u1ecdi l\u00e0 x\u1eed l\u00fd h\u00e0ng lo\u1ea1t \u0111\u1ec3 qu\u00e9t v\u00e0 x\u1eed l\u00fd c\u00e1c t\u1eadp d\u1eef li\u1ec7u l\u1edbn m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3. N\u00f3 th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c tr\u00ean nhi\u1ec1u h\u00e0ng c\u00f9ng m\u1ed9t l\u00fac, gi\u00fap n\u00e2ng cao hi\u1ec7u su\u1ea5t cho c\u00e1c truy v\u1ea5n ph\u00e2n t\u00edch.<\/p>\n<h2>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a Ch\u1ec9 m\u1ee5c Columnstore trong SQL<\/h2>\n<ul>\n<li>\n<p><strong>N\u00e9n d\u1eef li\u1ec7u<\/strong>: C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a kho l\u01b0u tr\u1eef c\u1ed9t gi\u1ea3m \u0111\u00e1ng k\u1ec3 y\u00eau c\u1ea7u l\u01b0u tr\u1eef d\u1eef li\u1ec7u do \u0111\u1ecbnh d\u1ea1ng l\u01b0u tr\u1eef theo c\u1ed9t v\u00e0 k\u1ef9 thu\u1eadt n\u00e9n d\u1ef1a tr\u00ean t\u1eeb \u0111i\u1ec3n c\u1ee7a ch\u00fang.<\/p>\n<\/li>\n<li>\n<p><strong>Ch\u1ebf \u0111\u1ed9 x\u1eed l\u00fd h\u00e0ng lo\u1ea1t<\/strong>: Kh\u1ea3 n\u0103ng x\u1eed l\u00fd d\u1eef li\u1ec7u theo l\u00f4, thay v\u00ec theo h\u00e0ng, cho ph\u00e9p th\u1ef1c hi\u1ec7n truy v\u1ea5n nhanh h\u01a1n \u0111\u1ed1i v\u1edbi c\u00e1c t\u1eadp d\u1eef li\u1ec7u l\u1edbn.<\/p>\n<\/li>\n<li>\n<p><strong>\u0110\u1ea9y l\u00f9i v\u1ecb ng\u1eef<\/strong>: C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a kho c\u1ed9t h\u1ed7 tr\u1ee3 \u0111\u1ea9y xu\u1ed1ng v\u1ecb t\u1eeb, c\u00f3 ngh\u0129a l\u00e0 tr\u00ecnh t\u1ed1i \u01b0u h\u00f3a truy v\u1ea5n c\u00f3 th\u1ec3 l\u1ecdc d\u1eef li\u1ec7u \u1edf c\u1ea5p \u0111\u1ed9 l\u01b0u tr\u1eef tr\u01b0\u1edbc khi truy xu\u1ea5t, n\u00e2ng cao h\u01a1n n\u1eefa hi\u1ec7u su\u1ea5t truy v\u1ea5n.<\/p>\n<\/li>\n<li>\n<p><strong>Th\u1ef1c thi Vector h\u00f3a<\/strong>: C\u00e1c thao t\u00e1c tr\u00ean to\u00e0n b\u1ed9 vect\u01a1 d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n \u0111\u1ed3ng th\u1eddi, gi\u00fap c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 th\u1ef1c hi\u1ec7n truy v\u1ea5n.<\/p>\n<\/li>\n<\/ul>\n<h2>C\u00e1c lo\u1ea1i ch\u1ec9 m\u1ee5c Columnstore trong SQL<\/h2>\n<p>C\u00f3 hai lo\u1ea1i ch\u1ec9 m\u1ee5c Columnstore trong SQL:<\/p>\n<ol>\n<li>\n<p><strong>Ch\u1ec9 m\u1ee5c c\u1eeda h\u00e0ng c\u1ed9t theo c\u1ee5m (CCI)<\/strong>:<\/p>\n<ul>\n<li>M\u1ed7i b\u1ea3ng ch\u1ec9 c\u00f3 th\u1ec3 c\u00f3 m\u1ed9t CCI.<\/li>\n<li>To\u00e0n b\u1ed9 b\u1ea3ng \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i th\u00e0nh \u0111\u1ecbnh d\u1ea1ng c\u1ed9t n\u00e9n.<\/li>\n<li>L\u00fd t\u01b0\u1edfng cho kh\u1ed1i l\u01b0\u1ee3ng c\u00f4ng vi\u1ec7c l\u01b0u tr\u1eef d\u1eef li\u1ec7u l\u1edbn v\u00e0 ph\u00e2n t\u00edch.<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>Ch\u1ec9 m\u1ee5c c\u1eeda h\u00e0ng c\u1ed9t kh\u00f4ng ph\u00e2n c\u1ee5m (NCCI)<\/strong>:<\/p>\n<ul>\n<li>Nhi\u1ec1u NCCI c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o tr\u00ean m\u1ed9t b\u1ea3ng.<\/li>\n<li>Ch\u1ec9 c\u00e1c c\u1ed9t \u0111\u01b0\u1ee3c ch\u1ecdn m\u1edbi \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i th\u00e0nh \u0111\u1ecbnh d\u1ea1ng c\u1ed9t n\u00e9n, ph\u1ea7n c\u00f2n l\u1ea1i \u1edf \u0111\u1ecbnh d\u1ea1ng d\u1ef1a tr\u00ean h\u00e0ng.<\/li>\n<li>Th\u00edch h\u1ee3p cho c\u00e1c t\u00ecnh hu\u1ed1ng trong \u0111\u00f3 c\u00e1c c\u1ed9t nh\u1ea5t \u0111\u1ecbnh \u0111\u01b0\u1ee3c truy v\u1ea5n th\u01b0\u1eddng xuy\u00ean h\u01a1n c\u00e1c c\u1ed9t kh\u00e1c.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>D\u01b0\u1edbi \u0111\u00e2y l\u00e0 b\u1ea3ng t\u00f3m t\u1eaft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa CCI v\u00e0 NCCI:<\/p>\n<table>\n<thead>\n<tr>\n<th>T\u00ednh n\u0103ng<\/th>\n<th>Ch\u1ec9 m\u1ee5c c\u1eeda h\u00e0ng c\u1ed9t theo c\u1ee5m (CCI)<\/th>\n<th>Ch\u1ec9 m\u1ee5c c\u1eeda h\u00e0ng c\u1ed9t kh\u00f4ng ph\u00e2n c\u1ee5m (NCCI)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Chuy\u1ec3n \u0111\u1ed5i b\u1ea3ng<\/td>\n<td>To\u00e0n b\u1ed9 b\u1ea3ng \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i sang \u0111\u1ecbnh d\u1ea1ng c\u1ed9t<\/td>\n<td>Ch\u1ec9 c\u00e1c c\u1ed9t \u0111\u00e3 ch\u1ecdn m\u1edbi \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i<\/td>\n<\/tr>\n<tr>\n<td>S\u1ed1 l\u01b0\u1ee3ng ch\u1ec9 m\u1ee5c<\/td>\n<td>Ch\u1ec9 cho ph\u00e9p m\u1ed9t CCI tr\u00ean m\u1ed7i b\u1ea3ng<\/td>\n<td>Nhi\u1ec1u NCCI c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o tr\u00ean m\u1ed9t b\u1ea3ng<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u su\u1ea5t truy v\u1ea5n<\/td>\n<td>N\u00f3i chung nhanh h\u01a1n do l\u01b0u tr\u1eef c\u1ed9t ho\u00e0n ch\u1ec9nh<\/td>\n<td>Hi\u1ec7u su\u1ea5t truy v\u1ea5n ph\u1ee5 thu\u1ed9c v\u00e0o vi\u1ec7c ch\u1ecdn c\u1ed9t<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng, th\u00e1ch th\u1ee9c v\u00e0 gi\u1ea3i ph\u00e1p<\/h2>\n<p>C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore r\u1ea5t c\u00f3 l\u1ee3i cho c\u00e1c truy v\u1ea5n ph\u00e2n t\u00edch li\u00ean quan \u0111\u1ebfn vi\u1ec7c x\u1eed l\u00fd d\u1eef li\u1ec7u quy m\u00f4 l\u1edbn. Tuy nhi\u00ean, ch\u00fang c\u00f3 th\u1ec3 kh\u00f4ng ph\u00f9 h\u1ee3p v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng c\u00f4ng vi\u1ec7c OLTP (X\u1eed l\u00fd giao d\u1ecbch tr\u1ef1c tuy\u1ebfn), bao g\u1ed3m c\u00e1c giao d\u1ecbch v\u00e0 c\u1eadp nh\u1eadt quy m\u00f4 nh\u1ecf th\u01b0\u1eddng xuy\u00ean. Trong nh\u1eefng tr\u01b0\u1eddng h\u1ee3p nh\u01b0 v\u1eady, c\u00e1c ch\u1ec9 m\u1ee5c d\u1ef1a tr\u00ean h\u00e0ng truy\u1ec1n th\u1ed1ng ho\u1ea1t \u0111\u1ed9ng t\u1ed1t h\u01a1n.<\/p>\n<p>Nh\u1eefng th\u00e1ch th\u1ee9c v\u1edbi ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore bao g\u1ed3m:<\/p>\n<ul>\n<li>\n<p><strong>Ch\u00e8n v\u00e0 c\u1eadp nh\u1eadt hi\u1ec7u su\u1ea5t<\/strong>: C\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a kho c\u1ed9t c\u00f3 th\u1ec3 c\u00f3 hi\u1ec7u su\u1ea5t ch\u00e8n v\u00e0 c\u1eadp nh\u1eadt ch\u1eadm h\u01a1n so v\u1edbi c\u00e1c ch\u1ec9 m\u1ee5c d\u1ef1a tr\u00ean h\u00e0ng, v\u00ec ch\u00fang y\u00eau c\u1ea7u t\u1ea3i d\u1eef li\u1ec7u h\u00e0ng lo\u1ea1t \u0111\u1ec3 c\u00f3 hi\u1ec7u su\u1ea5t t\u1ed1i \u01b0u.<\/p>\n<\/li>\n<li>\n<p><strong>C\u1eeda h\u00e0ng Delta<\/strong>: \u0110\u1ec3 x\u1eed l\u00fd c\u00e1c b\u1ea3n c\u1eadp nh\u1eadt m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3, SQL Server duy tr\u00ec m\u1ed9t C\u1eeda h\u00e0ng Delta d\u00e0nh cho d\u1eef li\u1ec7u ch\u01b0a \u0111\u01b0\u1ee3c cam k\u1ebft, \u0111\u01b0\u1ee3c h\u1ee3p nh\u1ea5t \u0111\u1ecbnh k\u1ef3 v\u00e0o C\u1eeda h\u00e0ng C\u1ed9t ch\u00ednh. Qu\u00e1 tr\u00ecnh n\u00e0y c\u00f3 th\u1ec3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t truy v\u1ea5n trong qu\u00e1 tr\u00ecnh h\u1ee3p nh\u1ea5t.<\/p>\n<\/li>\n<\/ul>\n<p>Gi\u1ea3i ph\u00e1p cho nh\u1eefng th\u00e1ch th\u1ee9c n\u00e0y bao g\u1ed3m:<\/p>\n<ul>\n<li>\n<p><strong>C\u1eadp nh\u1eadt h\u00e0ng lo\u1ea1t<\/strong>: Th\u1ef1c hi\u1ec7n c\u1eadp nh\u1eadt theo \u0111\u1ee3t l\u1edbn h\u01a1n c\u00f3 th\u1ec3 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t b\u1eb1ng c\u00e1ch gi\u1ea3m t\u1ea7n su\u1ea5t h\u1ee3p nh\u1ea5t Delta Store.<\/p>\n<\/li>\n<li>\n<p><strong>Ph\u00e2n \u0111o\u1ea1n d\u1eef li\u1ec7u<\/strong>: Ph\u00e2n \u0111o\u1ea1n d\u1eef li\u1ec7u th\u00e0nh c\u00e1c \u0111\u01a1n v\u1ecb nh\u1ecf h\u01a1n c\u00f3 th\u1ec3 h\u1ed7 tr\u1ee3 c\u00e1c ho\u1ea1t \u0111\u1ed9ng ch\u00e8n v\u00e0 c\u1eadp nh\u1eadt nhanh h\u01a1n.<\/p>\n<\/li>\n<\/ul>\n<h2>\u0110\u1eb7c \u0111i\u1ec3m v\u00e0 so s\u00e1nh<\/h2>\n<p>H\u00e3y so s\u00e1nh c\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore v\u1edbi c\u00e1c t\u00ednh n\u0103ng c\u01a1 s\u1edf d\u1eef li\u1ec7u t\u01b0\u01a1ng t\u1ef1:<\/p>\n<table>\n<thead>\n<tr>\n<th>T\u00ednh n\u0103ng<\/th>\n<th>Ch\u1ec9 m\u1ee5c c\u1ed9t<\/th>\n<th>Ch\u1ec9 m\u1ee5c Rowstore<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u0110\u1ecbnh d\u1ea1ng l\u01b0u tr\u1eef<\/td>\n<td>L\u01b0u tr\u1eef c\u1ed9t<\/td>\n<td>L\u01b0u tr\u1eef theo h\u00e0ng<\/td>\n<\/tr>\n<tr>\n<td>N\u00e9n<\/td>\n<td>T\u1ef7 l\u1ec7 n\u00e9n cao<\/td>\n<td>T\u1ef7 l\u1ec7 n\u00e9n th\u1ea5p h\u01a1n<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u su\u1ea5t truy v\u1ea5n<\/td>\n<td>Truy v\u1ea5n ph\u00e2n t\u00edch nhanh h\u01a1n<\/td>\n<td>Truy v\u1ea5n OLTP nhanh h\u01a1n<\/td>\n<\/tr>\n<tr>\n<td>Ch\u00e8n v\u00e0 c\u1eadp nh\u1eadt hi\u1ec7u su\u1ea5t<\/td>\n<td>C\u1eadp nh\u1eadt ri\u00eang l\u1ebb ch\u1eadm h\u01a1n<\/td>\n<td>C\u1eadp nh\u1eadt ri\u00eang l\u1ebb nhanh h\u01a1n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m v\u00e0 c\u00f4ng ngh\u1ec7 t\u01b0\u01a1ng lai<\/h2>\n<p>Khi d\u1eef li\u1ec7u ti\u1ebfp t\u1ee5c t\u0103ng theo c\u1ea5p s\u1ed1 nh\u00e2n, c\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore s\u1ebd v\u1eabn l\u00e0 m\u1ed9t th\u00e0nh ph\u1ea7n quan tr\u1ecdng c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u hi\u1ec7n \u0111\u1ea1i. Nh\u1eefng ti\u1ebfn b\u1ed9 trong t\u01b0\u01a1ng lai c\u00f3 th\u1ec3 t\u1eadp trung v\u00e0o vi\u1ec7c gi\u1ea3i quy\u1ebft c\u00e1c th\u00e1ch th\u1ee9c li\u00ean quan \u0111\u1ebfn c\u1eadp nh\u1eadt v\u00e0 cung c\u1ea5p c\u00e1c thu\u1eadt to\u00e1n n\u00e9n hi\u1ec7u qu\u1ea3 h\u01a1n n\u1eefa.<\/p>\n<h2>M\u00e1y ch\u1ee7 proxy v\u00e0 ch\u1ec9 m\u1ee5c kho l\u01b0u tr\u1eef c\u1ed9t trong SQL<\/h2>\n<p>M\u00e1y ch\u1ee7 proxy do OneProxy cung c\u1ea5p c\u00f3 th\u1ec3 n\u00e2ng cao hi\u1ec7u su\u1ea5t tri\u1ec3n khai SQL Server b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng ch\u1ec9 m\u1ee5c Columnstore. B\u1eb1ng c\u00e1ch \u0111\u1ecbnh tuy\u1ebfn c\u00e1c truy v\u1ea5n SQL th\u00f4ng qua m\u00e1y ch\u1ee7 proxy, c\u00e1c t\u1ed5 ch\u1ee9c c\u00f3 th\u1ec3 gi\u1ea3m b\u1edbt m\u1ed9t s\u1ed1 chi ph\u00ed x\u1eed l\u00fd v\u00e0 c\u00f3 kh\u1ea3 n\u0103ng c\u1ea3i thi\u1ec7n th\u1eddi gian ph\u1ea3n h\u1ed3i cho c\u00e1c m\u00e1y kh\u00e1ch t\u1eeb xa. Ngo\u00e0i ra, kh\u1ea3 n\u0103ng c\u00e2n b\u1eb1ng t\u1ea3i c\u1ee7a OneProxy c\u00f3 th\u1ec3 gi\u00fap ph\u00e2n ph\u1ed1i \u0111\u1ed3ng \u0111\u1ec1u c\u00e1c truy v\u1ea5n, t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c s\u1eed d\u1ee5ng t\u00e0i nguy\u00ean.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<p>\u0110\u1ec3 bi\u1ebft th\u00eam th\u00f4ng tin v\u1ec1 ch\u1ec9 m\u1ee5c Columnstore trong SQL, h\u00e3y tham kh\u1ea3o c\u00e1c t\u00e0i nguy\u00ean sau:<\/p>\n<ul>\n<li><a href=\"https:\/\/docs.microsoft.com\/en-us\/sql\/relational-databases\/indexes\/columnstore-indexes-overview?view=sql-server-ver15\" target=\"_new\" rel=\"noopener nofollow\">Microsoft Docs tr\u00ean c\u00e1c ch\u1ec9 m\u1ee5c c\u1ee7a Columnstore<\/a><\/li>\n<li><a href=\"https:\/\/www.sqlservercentral.com\/steps\/columnstore-indexes-introduction\" target=\"_new\" rel=\"noopener nofollow\">Trung t\u00e2m m\u00e1y ch\u1ee7 SQL: Gi\u1edbi thi\u1ec7u v\u1ec1 ch\u1ec9 m\u1ee5c Columnstore<\/a><\/li>\n<li><a href=\"https:\/\/www.red-gate.com\/hub\/product-learning\/sql-prompt\/development-and-testing-benefits-of-data-compression-in-sql-server\" target=\"_new\" rel=\"noopener nofollow\">N\u00e9n d\u1eef li\u1ec7u trong SQL Server<\/a><\/li>\n<\/ul>","protected":false},"featured_media":467910,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-476326","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Columnstore Indexes in SQL: An Overview<\/mark>","faq_items":[{"question":"What are Columnstore indexes in SQL, and how do they work?","answer":"<p>Columnstore indexes in SQL are a database feature that organizes and stores data in a columnar format rather than the traditional row-based storage. This arrangement allows for improved data compression and faster query performance for analytical workloads. Data within each column is stored and processed together, leveraging batch processing techniques. The indexes consist of column segments and dictionaries, which facilitate efficient data retrieval and compression.<\/p>"},{"question":"What is the history behind the origin of Columnstore indexes in SQL?","answer":"<p>Columnstore indexes in SQL were first introduced by Microsoft with the release of SQL Server 2012. The concept of columnar storage has been around since the 1970s, but it gained popularity in the mid-2000s with the rise of big data and the need for better data compression and query performance. Microsoft's implementation marked a significant advancement in this area, making it a standard feature in modern database management systems.<\/p>"},{"question":"How do Clustered Columnstore Indexes (CCI) differ from Non-Clustered Columnstore Indexes (NCCI)?","answer":"<p>Clustered Columnstore Indexes (CCI) convert the entire table into a columnar format, allowing only one CCI per table. On the other hand, Non-Clustered Columnstore Indexes (NCCI) allow multiple indexes on a single table and only convert selected columns into a columnar format. CCI tends to have faster query performance due to complete columnar storage, while NCCI's performance depends on the selection of columns.<\/p>"},{"question":"What are the key features of Columnstore indexes in SQL?","answer":"<p>Some key features of Columnstore indexes include:<\/p><ul><li>High data compression ratios, leading to reduced storage requirements.<\/li><li>Batch mode processing for faster execution of large analytical queries.<\/li><li>Predicate pushdown, allowing for filtering data at the storage level before retrieval.<\/li><li>Vectorized execution for improved query execution speeds.<\/li><\/ul>"},{"question":"What are the main challenges faced with Columnstore indexes?","answer":"<p>While Columnstore indexes offer significant benefits for analytical queries, they can present challenges, such as slower insert and update performance. This is due to the need for bulk loading data for optimal performance. Additionally, the maintenance of a Delta Store for uncommitted data can impact query performance during merges.<\/p>"},{"question":"How can organizations overcome the challenges of Columnstore indexes?","answer":"<p>To improve insert and update performance, organizations can opt for batch updates, performing updates in larger batches. Segmenting data into smaller units can also aid in faster insert and update operations.<\/p>"},{"question":"How can OneProxy's proxy servers enhance SQL Server deployments with Columnstore indexes?","answer":"<p>OneProxy's proxy servers can optimize SQL Server deployments using Columnstore indexes by offloading some processing overhead and potentially improving response times for remote clients. Additionally, OneProxy's load balancing capabilities help distribute queries evenly, optimizing resource usage and enhancing overall performance.<\/p>"},{"question":"What is the future outlook for Columnstore indexes in SQL?","answer":"<p>Columnstore indexes are expected to remain a crucial component of modern databases as data continues to grow exponentially. Future advancements may focus on addressing challenges related to updates and providing even more efficient compression algorithms.<\/p>"},{"question":"Where can I find more information about Columnstore indexes in SQL?","answer":"<p>For more in-depth insights on Columnstore indexes in SQL, you can refer to the following resources:<\/p><ul><li>Microsoft Docs on Columnstore Indexes: <a href=\"https:\/\/docs.microsoft.com\/en-us\/sql\/relational-databases\/indexes\/columnstore-indexes-overview?view=sql-server-ver15\" target=\"_new\">Link<\/a><\/li><li>SQL Server Central: Introduction to Columnstore Indexes: <a href=\"https:\/\/www.sqlservercentral.com\/steps\/columnstore-indexes-introduction\" target=\"_new\">Link<\/a><\/li><li>Data Compression in SQL Server: <a href=\"https:\/\/www.red-gate.com\/hub\/product-learning\/sql-prompt\/development-and-testing-benefits-of-data-compression-in-sql-server\" target=\"_new\">Link<\/a><\/li><\/ul>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/476326","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\/476326\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/467910"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=476326"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}