Memcached 闆嗙兢鏋舵瀯鏂归潰鐨勯棶棰?杞
銆€memcached鏄€庝箞宸ヤ綔鐨勶紵
銆€銆€Memcached鐨勭濂囨潵鑷袱闃舵鍝堝笇锛坱wo-stage hash锛夈€侻emcached灏卞儚涓€涓法澶х殑銆佸瓨鍌ㄤ簡寰堝<key,value>瀵圭殑鍝堝笇琛ㄣ€傞€氳繃key锛屽彲浠ュ瓨鍌ㄦ垨鏌ヨ浠绘剰鐨勬暟鎹€?/p>
銆€銆€瀹㈡埛绔彲浠ユ妸鏁版嵁瀛樺偍鍦ㄥ鍙癿emcached涓娿€傚綋鏌ヨ鏁版嵁鏃讹紝瀹㈡埛绔鍏堝弬鑰冭妭鐐瑰垪琛ㄨ绠楀嚭key鐨勫搱甯屽€硷紙闃舵涓€鍝堝笇锛夛紝杩涜€岄€変腑涓€涓妭 鐐癸紱瀹㈡埛绔皢璇锋眰鍙戦€佺粰閫変腑鐨勮妭鐐癸紝鐒跺悗memcached鑺傜偣閫氳繃涓€涓唴閮ㄧ殑鍝堝笇绠楁硶锛堥樁娈典簩鍝堝笇锛夛紝鏌ユ壘鐪熸鐨勬暟鎹紙item锛夈€?/p>
銆€銆€涓句釜鍒楀瓙锛屽亣璁炬湁3涓鎴风1, 2, 3锛?鍙癿emcached A, B, C锛?br>銆€銆€Client 1鎯虫妸鏁版嵁"barbaz"浠ey "foo"瀛樺偍銆侰lient 1棣栧厛鍙傝€冭妭鐐瑰垪琛紙A, B, C锛夛紝璁＄畻key "foo"鐨勫搱甯屽€硷紝鍋囪memcached B琚€変腑銆傛帴鐫€锛孋lient 1鐩存帴connect鍒癿emcached B锛岄€氳繃key "foo"鎶婃暟鎹?barbaz"瀛樺偍杩涘幓銆傘€€銆€Client 2浣跨敤涓嶤lient 1鐩稿悓鐨勫鎴风搴擄紙鎰忓懗鐫€闃舵涓€鐨勫搱甯岀畻娉曠浉鍚岋級锛屼篃鎷ユ湁鍚屾牱鐨刴emcached鍒楄〃锛圓, B, C锛夈€?br>銆€銆€浜庢槸锛岀粡杩囩浉鍚岀殑鍝堝笇璁＄畻锛堥樁娈典竴锛夛紝Client 2璁＄畻鍑簁ey "foo"鍦╩emcached B涓婏紝鐒跺悗瀹冪洿鎺ヨ姹俶emcached B锛屽緱鍒版暟鎹?barbaz"銆?/p>
銆€銆€鍚勭瀹㈡埛绔湪memcached涓暟鎹殑瀛樺偍褰㈠紡鏄笉鍚岀殑锛坧erl Storable, php serialize, java hibernate, JSON绛夛級銆備竴浜涘鎴风瀹炵幇鐨勫搱甯岀畻娉曚篃涓嶄竴鏍枫€備絾鏄紝memcached鏈嶅姟鍣ㄧ鐨勮涓烘€绘槸涓€鑷寸殑銆?/p>
銆€銆€鏈€鍚庯紝浠庡疄鐜扮殑瑙掑害鐪嬶紝memcached鏄竴涓潪闃诲鐨勩€佸熀浜庝簨浠剁殑鏈嶅姟鍣ㄧ▼搴忋€傝繖绉嶆灦鏋勫彲浠ュ緢濂藉湴瑙ｅ喅C10K problem 锛屽苟鍏锋湁鏋佷匠鐨勫彲鎵╁睍鎬с€?/p>
銆€銆€鍙互鍙傝€?a href="http://code.google.com/p/memcached/wiki/TutorialCachingStory">A Story of Caching 锛岃繖绡囨枃绔犵畝鍗曡В閲婁簡瀹㈡埛绔笌memcached鏄浣曚氦浜掔殑銆?/p>
銆€銆€memcached鏈€澶х殑浼樺娍鏄粈涔堬紵
銆€銆€璇蜂粩缁嗛槄璇讳笂闈㈢殑闂锛堝嵆memcached鏄浣曞伐浣滅殑锛夈€侻emcached鏈€澶х殑濂藉灏辨槸瀹冨甫鏉ヤ簡鏋佷匠鐨勬按骞冲彲鎵╁睍鎬э紝鐗瑰埆鏄湪涓€涓法澶?鐨勭郴缁熶腑銆傜敱浜庡鎴风鑷繁鍋氫簡涓€娆″搱甯岋紝閭ｄ箞鎴戜滑寰堝鏄撳鍔犲ぇ閲弇emcached鍒伴泦缇や腑銆俶emcached涔嬮棿娌℃湁鐩镐簰閫氫俊锛屽洜姝や笉浼氬鍔?memcached鐨勮礋杞斤紱娌℃湁澶氭挱鍗忚锛屼笉浼氱綉缁滈€氫俊閲忕垎鐐革紙implode锛夈€俶emcached鐨勯泦缇ゅ緢濂界敤銆傚唴瀛樹笉澶熶簡锛熷鍔犲嚑鍙?memcached鍚э紱CPU涓嶅鐢ㄤ簡锛熷啀澧炲姞鍑犲彴鍚э紱鏈夊浣欑殑鍐呭瓨锛熷湪澧炲姞鍑犲彴鍚э紝涓嶈娴垂浜嗐€?/p>
銆€銆€鍩轰簬memcached鐨勫熀鏈師鍒欙紝鍙互鐩稿綋杞绘澗鍦版瀯寤哄嚭涓嶅悓绫诲瀷鐨勭紦瀛樻灦鏋勩€傞櫎浜嗚繖绡嘑AQ锛屽湪鍏朵粬鍦版柟寰堝鏄撴壘鍒拌缁嗚祫鏂欑殑銆?/p>
銆€銆€鐪嬬湅涓嬮潰鐨勫嚑涓棶棰樺惂锛屽畠浠湪memcached銆佹湇鍔″櫒鐨刲ocal cache鍜孧ySQL鐨剄uery cache涔嬮棿鍋氫簡姣旇緝銆傝繖鍑犱釜闂浼氳鎮ㄦ湁鏇村叏闈㈢殑璁よ瘑銆?/p>
銆€銆€memcached鍜孧ySQL鐨剄uery cache鐩告瘮锛屾湁浠€涔堜紭缂虹偣锛?/span>
銆€銆€鎶妋emcached寮曞叆搴旂敤涓紝杩樻槸闇€瑕佷笉灏戝伐浣滈噺鐨勩€侻ySQL鏈変釜浣跨敤鏂逛究鐨剄uery cache锛屽彲浠ヨ嚜鍔ㄥ湴缂撳瓨SQL鏌ヨ鐨勭粨鏋滐紝琚紦瀛樼殑SQL鏌ヨ鍙互琚弽澶嶅湴蹇€熸墽琛屻€侻emcached涓庝箣鐩告瘮锛屾€庝箞鏍峰憿锛烳ySQL鐨剄uery cache鏄泦涓紡鐨勶紝杩炴帴鍒拌query cache鐨凪ySQL鏈嶅姟鍣ㄩ兘浼氬彈鐩娿€?/p>
- 褰撴偍淇敼琛ㄦ椂锛孧ySQL鐨剄uery cache浼氱珛鍒昏鍒锋柊锛坒lush锛夈€傚瓨鍌ㄤ竴涓猰emcached item鍙渶瑕佸緢灏戠殑鏃堕棿锛屼絾鏄綋鍐欐搷浣滃緢棰戠箒鏃讹紝MySQL鐨剄uery cache浼氱粡甯歌鎵€鏈夌紦瀛樻暟鎹兘澶辨晥銆?/li>
- 鍦ㄥ鏍窩PU涓婏紝MySQL鐨剄uery cache浼氶亣鍒版墿灞曢棶棰橈紙scalability issues锛夈€傚湪澶氭牳CPU涓婏紝query cache浼氬鍔犱竴涓叏灞€閿侊紙global lock锛? 鐢变簬闇€瑕佸埛鏂版洿澶氱殑缂撳瓨鏁版嵁锛岄€熷害浼氬彉寰楁洿鎱€?/li>
- 鍦∕ySQL鐨剄uery cache涓紝鎴戜滑鏄笉鑳藉瓨鍌ㄤ换鎰忕殑鏁版嵁鐨勶紙鍙兘鏄疭QL鏌ヨ缁撴灉锛夈€傝€屽埄鐢╩emcached锛屾垜浠彲浠ユ惌寤哄嚭鍚勭楂樻晥鐨勭紦瀛樸€傛瘮濡傦紝鍙互鎵ц澶氫釜鐙珛 鐨勬煡璇紝鏋勫缓鍑轰竴涓敤鎴峰璞★紙user object锛夛紝鐒跺悗灏嗙敤鎴峰璞＄紦瀛樺埌memcached涓€傝€宷uery cache鏄疭QL璇彞绾у埆鐨勶紝涓嶅彲鑳藉仛鍒拌繖涓€鐐广€傚湪灏忕殑缃戠珯涓紝query cache浼氭湁鎵€甯姪锛屼絾闅忕潃缃戠珯瑙勬ā鐨勫鍔狅紝query cache鐨勫紛灏嗗ぇ浜庡埄銆?/li>
- query cache鑳藉鍒╃敤鐨勫唴瀛樺閲忓彈鍒癕ySQL鏈嶅姟鍣ㄧ┖闂插唴瀛樼┖闂寸殑闄愬埗銆傜粰鏁版嵁搴撴湇鍔″櫒澧炲姞鏇村鐨勫唴瀛樻潵缂撳瓨鏁版嵁锛屽浐鐒舵槸寰堝ソ鐨勩€備絾鏄紝鏈変簡memcached锛屽彧瑕佹偍鏈夌┖闂茬殑鍐呭瓨锛岄兘鍙互鐢ㄦ潵澧炲姞memcached闆嗙兢鐨勮妯★紝鐒跺悗鎮ㄥ氨鍙互缂撳瓨鏇村鐨勬暟鎹€?/li>
銆€銆€memcached鍜屾湇鍔″櫒鐨刲ocal cache锛堟瘮濡侾HP鐨凙PC銆乵map鏂囦欢绛夛級鐩告瘮锛屾湁浠€涔堜紭缂虹偣锛?/span>
銆€銆€棣栧厛锛宭ocal cache鏈夎澶氫笌涓婇潰(query cache)鐩稿悓鐨勯棶棰樸€俵ocal cache鑳藉鍒╃敤鐨勫唴瀛樺閲忓彈鍒帮紙鍗曞彴锛夋湇鍔″櫒绌洪棽鍐呭瓨绌洪棿鐨勯檺鍒躲€備笉杩囷紝local cache鏈変竴鐐规瘮memcached鍜宷uery cache閮借濂斤紝閭ｅ氨鏄畠涓嶄絾鍙互瀛樺偍浠绘剰鐨勬暟鎹紝鑰屼笖娌℃湁缃戠粶瀛樺彇鐨勫欢杩熴€?/p>
- local cache鐨勬暟鎹煡璇㈡洿蹇€傝€冭檻鎶奾ighly common鐨勬暟鎹斁鍦╨ocal cache涓惂銆傚鏋滄瘡涓〉闈㈤兘闇€瑕佸姞杞戒竴浜涙暟閲忚緝灏戠殑鏁版嵁锛岃€冭檻鎶婂畠浠斁鍦╨ocal cached鍚с€?/li>
- local cache缂哄皯闆嗕綋澶辨晥锛坓roup invalidation锛夌殑鐗规€с€傚湪memcached闆嗙兢涓紝鍒犻櫎鎴栨洿鏂颁竴涓猭ey浼氳鎵€鏈夌殑瑙傚療鑰呰瀵熷埌銆備絾鏄湪local cache涓? 鎴戜滑鍙兘閫氱煡鎵€鏈夌殑鏈嶅姟鍣ㄥ埛鏂癱ache锛堝緢鎱紝涓嶅叿鎵╁睍鎬э級锛屾垨鑰呬粎浠呬緷璧栫紦瀛樿秴鏃跺け鏁堟満鍒躲€?/li>
- local cache闈复鐫€涓ラ噸鐨勫唴瀛橀檺鍒讹紝杩欎竴鐐逛笂闈㈠凡缁忔彁鍒般€?/li>
銆€銆€memcached鐨刢ache鏈哄埗鏄€庢牱鐨勶紵
銆€銆€Memcached涓昏鐨刢ache鏈哄埗鏄疞RU锛堟渶杩戞渶灏戠敤锛夌畻娉?瓒呮椂澶辨晥銆傚綋鎮ㄥ瓨鏁版嵁鍒癿emcached涓紝鍙互鎸囧畾璇ユ暟鎹湪缂撳瓨涓彲 浠ュ憜澶氫箙Which is forever, or some time in the future銆傚鏋渕emcached鐨勫唴瀛樹笉澶熺敤浜嗭紝杩囨湡鐨剆labs浼氫紭鍏堣鏇挎崲锛屾帴鐫€灏辫疆鍒版渶鑰佺殑鏈浣跨敤鐨剆labs銆?/p>
銆€銆€memcached濡備綍瀹炵幇鍐椾綑鏈哄埗锛?/span> 銆€銆€memcached濡備綍澶勭悊瀹归敊鐨勶紵 銆€銆€濡備綍灏唌emcached涓璱tem鎵归噺瀵煎叆瀵煎嚭锛?/span> 銆€銆€鎮ㄤ笉搴旇杩欐牱鍋氾紒Memcached鏄竴涓潪闃诲鐨勬湇鍔″櫒銆備换浣曞彲鑳藉鑷磎emcached鏆傚仠鎴栫灛鏃舵嫆缁濇湇鍔＄殑鎿嶄綔閮藉簲璇ュ€煎緱娣辨€濈啛铏戙€傚悜 memcached涓壒閲忓鍏ユ暟鎹線寰€涓嶆槸鎮ㄧ湡姝ｆ兂瑕佺殑锛佹兂璞＄湅锛屽鏋滅紦瀛樻暟鎹湪瀵煎嚭瀵煎叆涔嬮棿鍙戠敓浜嗗彉鍖栵紝鎮ㄥ氨闇€瑕佸鐞嗚剰鏁版嵁浜嗭紱濡傛灉缂撳瓨鏁版嵁鍦ㄥ鍑哄鍏?涔嬮棿杩囨湡浜嗭紝鎮ㄥ張鎬庝箞澶勭悊杩欎簺鏁版嵁鍛紵 銆€銆€鍥犳锛屾壒閲忓鍑哄鍏ユ暟鎹苟涓嶅儚鎮ㄦ兂璞′腑鐨勯偅涔堟湁鐢ㄣ€備笉杩囧湪涓€涓満鏅€掓槸寰堟湁鐢ㄣ€傚鏋滄偍鏈夊ぇ閲忕殑浠庝笉鍙樺寲鐨勬暟鎹紝骞朵笖甯屾湜缂撳瓨寰堝揩鐑紙warm锛夎捣鏉ワ紝鎵归噺瀵煎叆缂撳瓨鏁版嵁鏄緢鏈夊府鍔╃殑銆傝櫧鐒惰繖涓満鏅苟涓嶅吀鍨嬶紝浣嗗嵈缁忓父鍙戠敓锛屽洜姝ゆ垜浠細鑰冭檻鍦ㄥ皢鏉ュ疄鐜版壒閲忓鍑哄鍏ョ殑鍔熻兘銆?/p>
銆€銆€Steven Grimm锛屼竴濡傛棦寰€鍦?锛屽湪閭欢鍒楄〃涓粰鍑轰簡鍙︿竴涓緢濂界殑渚嬪瓙锛?a href="http://lists.danga.com/pipermail/memcached/2007-July/004802.html">http://lists.danga.com/pipermail/memcached/2007-July/004802.html 銆?/p>
銆€銆€浣嗘槸鎴戠‘瀹為渶瑕佹妸memcached涓殑item鎵归噺瀵煎嚭瀵煎叆锛屾€庝箞鍔烇紵锛?/span> 銆€銆€濂藉惂濂藉惂銆傚鏋滄偍闇€瑕佹壒閲忓鍑哄鍏ワ紝鏈€鍙兘鐨勫師鍥犱竴鑸槸閲嶆柊鐢熸垚缂撳瓨鏁版嵁闇€瑕佹秷鑰楀緢闀跨殑鏃堕棿锛屾垨鑰呮暟鎹簱鍧忎簡璁╂偍楗卞彈鐥涜嫤銆?/p>
銆€銆€濡傛灉涓€涓猰emcached鑺傜偣down浜嗚鎮ㄥ緢鐥涜嫤锛岄偅涔堟偍杩樹細闄峰叆鍏朵粬寰堝楹荤儲銆傛偍鐨勭郴缁熷お鑴嗗急浜嗐€傛偍闇€瑕佸仛涓€浜涗紭鍖栧伐浣溿€傛瘮濡傚鐞?鎯?缇?闂锛堟瘮濡?memcached鑺傜偣閮藉け鏁堜簡锛屽弽澶嶇殑鏌ヨ璁╂偍鐨勬暟鎹簱涓嶅牚閲嶈礋...杩欎釜闂鍦‵AQ鐨勫叾浠栨彁鍒拌繃锛夛紝鎴栬€呬紭鍖栦笉濂界殑鏌ヨ銆傝浣忥紝Memcached 骞朵笉鏄偍閫冮伩浼樺寲鏌ヨ鐨勫€熷彛銆?/p>
銆€銆€濡傛灉鎮ㄧ殑楹荤儲浠呬粎鏄噸鏂扮敓鎴愮紦瀛樻暟鎹渶瑕佹秷鑰楀緢闀挎椂闂达紙15绉掑埌瓒呰繃5鍒嗛挓锛夛紝鎮ㄥ彲浠ヨ€冭檻閲嶆柊浣跨敤鏁版嵁搴撱€傝繖閲岀粰鍑轰竴浜涙彁绀猴細 銆€銆€涓婇潰鐨勬柟娉曢兘鍙互寮曞叆memcached锛屽湪閲嶅惎memcached鐨勬椂鍊欎粛鐒舵彁渚涘緢濂界殑鎬ц兘銆傜敱浜庢偍涓嶉渶瑕佸綋蹇?hot"鐨刬tem琚?memcached LRU绠楁硶绐佺劧娣樻卑锛岀敤鎴峰啀涔熶笉鐢ㄨ姳鍑犲垎閽熸潵绛夊緟閲嶆柊鐢熸垚缂撳瓨鏁版嵁锛堝綋缂撳瓨鏁版嵁绐佺劧浠庡唴瀛樹腑娑堝け鏃讹級锛屽洜姝や笂闈㈢殑鏂规硶鍙互鍏ㄩ潰鎻愰珮鎬ц兘銆?/p>
銆€銆€鍏充簬杩欎簺鏂规硶鐨勭粏鑺傦紝璇﹁鍗氬锛?a href="http://dormando.livejournal.com/495593.html">http://dormando.livejournal.com/495593.html 銆?/p>
銆€銆€memcached鏄浣曞仛韬唤楠岃瘉鐨勶紵 銆€銆€濡傛灉鎮ㄥ笇鏈涢檺鍒惰闂紝鎮ㄥ彲浠ヤ娇鐢ㄩ槻鐏锛屾垨鑰呰memcached鐩戝惉unix domain socket銆?/p>
銆€銆€memcached鐨勫绾跨▼鏄粈涔堬紵濡備綍浣跨敤瀹冧滑锛?/span> 銆€銆€濡傛灉鎮ㄧ殑绯荤粺璐熻浇骞朵笉閲嶏紝涔熻鎮ㄤ笉闇€瑕佸惎鐢ㄥ绾跨▼宸ヤ綔妯″紡銆傚鏋滄偍鍦ㄨ繍琛屼竴涓嫢鏈夊ぇ瑙勬ā纭欢鐨勩€佸簽澶х殑缃戠珯锛屾偍灏嗕細鐪嬪埌澶氱嚎绋嬬殑濂藉銆?/p>
銆€銆€鏇村淇℃伅璇峰弬瑙侊細http://code.sixapart.com/svn/memcached/trunk/server/doc/threads.txt 銆?/p>
銆€銆€绠€鍗曞湴鎬荤粨涓€涓嬶細鍛戒护瑙ｆ瀽锛坢emcached鍦ㄨ繖閲岃姳浜嗗ぇ閮ㄥ垎鏃堕棿锛夊彲浠ヨ繍琛屽湪澶氱嚎绋嬫ā寮忎笅銆俶emcached鍐呴儴瀵规暟鎹殑鎿嶄綔鏄熀浜庡緢澶?鍏ㄥ眬閿佺殑锛堝洜姝よ繖閮ㄥ垎宸ヤ綔涓嶆槸澶氱嚎绋嬬殑锛夈€傛湭鏉ュ澶氱嚎绋嬫ā寮忕殑鏀硅繘锛屽皢绉婚櫎澶ч噺鐨勫叏灞€閿侊紝鎻愰珮memcached鍦ㄨ礋杞芥瀬楂樼殑鍦烘櫙涓嬬殑鎬ц兘銆?/p>
銆€銆€memcached鑳芥帴鍙楃殑key鐨勬渶澶ч暱搴︽槸澶氬皯锛?/span> 銆€銆€memcached瀵筰tem鐨勮繃鏈熸椂闂存湁浠€涔堥檺鍒讹紵 銆€銆€memcached鏈€澶ц兘瀛樺偍澶氬ぇ鐨勫崟涓猧tem锛?/span> 銆€銆€涓轰粈涔堝崟涓猧tem鐨勫ぇ灏忚闄愬埗鍦?M byte涔嬪唴锛?/span> 銆€銆€绠€鍗曠殑鍥炵瓟锛氬洜涓哄唴瀛樺垎閰嶅櫒鐨勭畻娉曞氨鏄繖鏍风殑銆?/p>
銆€銆€璇︾粏鐨勫洖绛旓細Memcached鐨勫唴瀛樺瓨鍌ㄥ紩鎿庯紙寮曟搸灏嗘潵鍙彃鎷?..锛夛紝浣跨敤slabs鏉ョ鐞嗗唴瀛樸€傚唴瀛樿鍒嗘垚澶у皬涓嶇瓑鐨剆labs chunks锛堝厛鍒嗘垚澶у皬鐩哥瓑鐨剆labs锛岀劧鍚庢瘡涓猻lab琚垎鎴愬ぇ灏忕浉绛塩hunks锛屼笉鍚宻lab鐨刢hunk澶у皬鏄笉鐩哥瓑鐨勶級銆俢hunk鐨勫ぇ灏?渚濇浠庝竴涓渶灏忔暟寮€濮嬶紝鎸夋煇涓洜瀛愬闀匡紝鐩村埌杈惧埌鏈€澶х殑鍙兘鍊笺€?/p>
銆€銆€濡傛灉鏈€灏忓€间负400B锛屾渶澶у€兼槸1MB锛屽洜瀛愭槸1.20锛屽悇涓猻lab鐨刢hunk鐨勫ぇ灏忎緷娆℃槸锛歴lab1 - 400B slab2 - 480B slab3 - 576B ... 銆€銆€slab涓璫hunk瓒婂ぇ锛屽畠鍜屽墠闈㈢殑slab涔嬮棿鐨勯棿闅欏氨瓒婂ぇ銆傚洜姝わ紝鏈€澶у€艰秺澶э紝鍐呭瓨鍒╃敤鐜囪秺浣庛€侻emcached蹇呴』涓烘瘡涓猻lab棰勫厛鍒嗛厤鍐呭瓨锛屽洜姝ゅ鏋滆缃簡杈冨皬鐨勫洜瀛愬拰杈冨ぇ鐨勬渶澶у€硷紝浼氶渶瑕佹洿澶氱殑鍐呭瓨銆?/p>
銆€銆€杩樻湁鍏朵粬鍘熷洜浣垮緱鎮ㄤ笉瑕佽繖鏍峰悜memcached涓瓨鍙栧緢澶х殑鏁版嵁...涓嶈灏濊瘯鎶婂法澶х殑缃戦〉鏀惧埌mencached涓€傛妸杩欐牱澶х殑鏁版嵁缁撴瀯load鍜寀npack鍒板唴瀛樹腑闇€瑕佽姳璐瑰緢闀跨殑鏃堕棿锛屼粠鑰屽鑷存偍鐨勭綉绔欐€ц兘鍙嶈€屼笉濂姐€?/p>
銆€銆€濡傛灉鎮ㄧ‘瀹為渶瑕佸瓨鍌ㄥぇ浜?MB鐨勬暟鎹紝浣犲彲浠ヤ慨鏀箂labs.c:POWER_BLOCK鐨勫€硷紝鐒跺悗閲嶆柊缂栬瘧memcached锛涙垨鑰呬娇鐢ㄤ綆鏁堢殑malloc/free銆傚叾浠栫殑寤鸿鍖呮嫭鏁版嵁搴撱€丮ogileFS绛夈€?/p>
銆€銆€鎴戝彲浠ュ湪涓嶅悓鐨刴emcached鑺傜偣涓婁娇鐢ㄥぇ灏忎笉绛夌殑缂撳瓨绌洪棿鍚楋紵杩欎箞鍋氫箣鍚庯紝memcached鑳藉鏇存湁鏁堝湴浣跨敤鍐呭瓨鍚楋紵 銆€銆€浠€涔堟槸浜岃繘鍒跺崗璁紝鎴戣鍏虫敞鍚楋紵 銆€銆€鍏充簬浜岃繘鍒舵渶濂界殑淇℃伅褰撶劧鏄簩杩涘埗鍗忚瑙勮寖锛?a href="http://code.google.com/p/memcached/wiki/MemcacheBinaryProtocol">http://code.google.com/p/memcached/wiki/MemcacheBinaryProtocol 銆?/p>
銆€銆€浜岃繘鍒跺崗璁皾璇曚负绔彁渚涗竴涓洿鏈夋晥鐨勩€佸彲闈犵殑鍗忚锛屽噺灏戝鎴风/鏈嶅姟鍣ㄧ鍥犲鐞嗗崗璁€屼骇鐢熺殑CPU鏃堕棿銆?br>鏍规嵁Facebook鐨勬祴璇曪紝瑙ｆ瀽ASCII鍗忚鏄痬emcached涓秷鑰桟PU鏃堕棿鏈€澶氱殑鐜妭銆傛墍浠ワ紝鎴戜滑涓轰粈涔堜笉鏀硅繘ASCII鍗忚鍛紵 銆€銆€鍦ㄨ繖涓偖浠跺垪琛ㄧ殑thread涓彲浠ユ壘鍒颁竴浜涙棫鐨勪俊鎭細http://lists.danga.com/pipermail/memcached/2007-July/004636.html 銆?/p>
銆€銆€memcached鐨勫唴瀛樺垎閰嶅櫒鏄浣曞伐浣滅殑锛熶负浠€涔堜笉閫傜敤malloc/free锛侊紵涓轰綍瑕佷娇鐢╯labs锛?/span> 銆€銆€slab鍒嗛厤鍣ㄥ氨鏄负浜嗚В鍐宠繖涓棶棰樿€岀敓鐨勩€傚唴瀛樿鍒嗛厤骞跺垝鍒嗘垚chunks锛屼竴鐩磋閲嶅浣跨敤銆傚洜涓哄唴瀛樿鍒掑垎鎴愬ぇ灏忎笉绛夌殑slabs锛屽鏋?item鐨勫ぇ灏忎笌琚€夋嫨瀛樻斁瀹冪殑slab涓嶆槸寰堝悎閫傜殑璇濓紝灏变細娴垂涓€浜涘唴瀛樸€係teven Grimm姝ｅ湪杩欐柟闈㈠凡缁忓仛鍑轰簡鏈夋晥鐨勬敼杩涖€?/p>
銆€銆€閭欢鍒楄〃涓湁涓€浜涘叧浜巗lab鐨勬敼杩涳紙power of n 杩樻槸 power of 2锛夊拰鏉冭 鏂规锛?a href="http://lists.danga.com/pipermail/memcached/2006-May/002163.html">http://lists.danga.com/pipermail/memcached/2006-May/002163.html http://lists.danga.com/pipermail/memcached/2007-March/003753.html 銆?/p>
銆€銆€濡傛灉鎮ㄦ兂浣跨敤malloc/free锛岀湅鐪嬪畠浠伐浣滃湴鎬庝箞鏍凤紝鎮ㄥ彲浠ュ湪鏋勫缓杩囩▼涓畾涔塙SE_SYSTEM_MALLOC銆傝繖涓壒鎬ф病鏈夌粡杩囧緢濂界殑娴嬭瘯锛屾墍浠ュお涓嶅彲鑳藉緱鍒板紑鍙戣€呯殑鏀寔銆?/p>
銆€銆€鏇村淇℃伅锛?a href="http://code.sixapart.com/svn/memcached/trunk/server/doc/memory_management.txt">http://code.sixapart.com/svn/memcached/trunk/server/doc/memory_management.txt 銆?/p>
銆€銆€memcached鏄師瀛愮殑鍚楋紵 銆€銆€memcached 1.2.5浠ュ強鏇撮珮鐗堟湰锛屾彁渚涗簡gets鍜宑as鍛戒护锛屽畠浠彲浠ヨВ鍐充笂闈㈢殑闂銆傚鏋滄偍浣跨敤gets鍛戒护鏌ヨ鏌愪釜key鐨刬tem锛宮emcached浼?缁欐偍杩斿洖璇tem褰撳墠鍊肩殑鍞竴鏍囪瘑銆傚鏋滄偍瑕嗗啓浜嗚繖涓猧tem骞舵兂鎶婂畠鍐欏洖鍒癿emcached涓紝鎮ㄥ彲浠ラ€氳繃cas鍛戒护鎶婇偅涓敮涓€鏍囪瘑涓€璧峰彂閫佺粰 memcached銆傚鏋滆item瀛樻斁鍦╩emcached涓殑鍞竴鏍囪瘑涓庢偍鎻愪緵鐨勪竴鑷达紝鎮ㄧ殑鍐欐搷浣滃皢浼氭垚鍔熴€傚鏋滃彟涓€涓繘绋嬪湪杩欐湡闂翠篃淇敼浜嗚繖涓?item锛岄偅涔堣item瀛樻斁鍦╩emcached涓殑鍞竴鏍囪瘑灏嗕細鏀瑰彉锛屾偍鐨勫啓鎿嶄綔灏变細澶辫触銆?/p>
銆€銆€閫氬父锛屽熀浜巑emcached涓璱tem鐨勫€兼潵淇敼item锛屾槸涓€浠舵鎵嬬殑浜嬫儏銆傞櫎闈炴偍寰堟竻妤氳嚜宸卞湪鍋氫粈涔堬紝鍚﹀垯璇蜂笉瑕佸仛杩欐牱鐨勪簨鎯呫€?/p>
聽 杞嚜锛歨ttp://kb.cnblogs.com/page/69074/
銆€ 銆€涓嶅疄鐜帮紒鎴戜滑瀵硅繖涓棶棰樻劅鍒板緢鎯婅銆侻emcached搴旇鏄簲鐢ㄧ殑缂撳瓨灞傘€傚畠鐨勮璁℃湰韬氨涓嶅甫鏈変换浣曞啑浣欐満鍒躲€傚鏋滀竴涓猰emcached鑺傜偣澶卞幓浜?鎵€鏈夋暟鎹紝鎮ㄥ簲璇ュ彲浠ヤ粠鏁版嵁婧愶紙姣斿鏁版嵁搴擄級鍐嶆鑾峰彇鍒版暟鎹€傛偍搴旇鐗瑰埆娉ㄦ剰锛屾偍鐨勫簲鐢ㄥ簲璇ュ彲浠ュ蹇嶈妭鐐圭殑澶辨晥銆備笉瑕佸啓涓€浜涚碂绯曠殑鏌ヨ浠ｇ爜锛屽瘎甯屾湜浜?memcached鏉ヤ繚璇佷竴鍒囷紒濡傛灉鎮ㄦ媴蹇冭妭鐐瑰け鏁堜細澶уぇ鍔犻噸鏁版嵁搴撶殑璐熸媴锛岄偅涔堟偍鍙互閲囧彇涓€浜涘姙娉曘€傛瘮濡傛偍鍙互澧炲姞鏇村鐨勮妭鐐癸紙鏉ュ噺灏戜涪澶变竴涓妭鐐圭殑褰?鍝嶏級锛岀儹澶囪妭鐐癸紙鍦ㄥ叾浠栬妭鐐筪own浜嗙殑鏃跺€欐帴绠P锛夛紝绛夌瓑銆?/p>
銆€銆€涓嶅鐞嗭紒:) 鍦╩emcached鑺傜偣澶辨晥鐨勬儏鍐典笅锛岄泦缇ゆ病鏈夊繀瑕佸仛浠讳綍瀹归敊澶勭悊銆傚鏋滃彂鐢熶簡鑺傜偣澶辨晥锛屽簲瀵圭殑鎺柦瀹屽叏鍙栧喅浜庣敤鎴枫€傝妭鐐瑰け鏁堟椂锛屼笅闈㈠垪鍑哄嚑绉嶆柟妗堜緵鎮ㄩ€夋嫨锛?/p>
銆€ 銆€娌℃湁韬唤璁よ瘉鏈哄埗锛乵emcached鏄繍琛屽湪搴旂敤涓嬪眰鐨勮蒋浠讹紙韬唤楠岃瘉搴旇鏄簲鐢ㄤ笂灞傜殑鑱岃矗锛夈€俶emcached鐨勫鎴风鍜屾湇鍔″櫒绔箣鎵€浠ユ槸杞婚噺绾?鐨勶紝閮ㄥ垎鍘熷洜灏辨槸瀹屽叏娌℃湁瀹炵幇韬唤楠岃瘉鏈哄埗銆傝繖鏍凤紝memcached鍙互寰堝揩鍦板垱寤烘柊杩炴帴锛屾湇鍔″櫒绔篃鏃犻渶浠讳綍閰嶇疆銆?/p>
銆€ 銆€绾跨▼灏辨槸瀹氬緥锛坱hreads rule锛夛紒鍦⊿teven Grimm鍜孎acebook鐨勫姫鍔涗笅锛宮emcached 1.2鍙婃洿楂樼増鏈嫢鏈変簡澶氱嚎绋嬫ā寮忋€傚绾跨▼妯″紡鍏佽memcached鑳藉鍏呭垎鍒╃敤澶氫釜CPU锛屽苟鍦–PU涔嬮棿鍏变韩鎵€鏈夌殑缂撳瓨鏁版嵁銆俶emcached浣?鐢ㄤ竴绉嶇畝鍗曠殑閿佹満鍒舵潵淇濊瘉鏁版嵁鏇存柊鎿嶄綔鐨勪簰鏂ャ€傜浉姣斿湪鍚屼竴涓墿鐞嗘満鍣ㄤ笂杩愯澶氫釜memcached瀹炰緥锛岃繖绉嶆柟寮忚兘澶熸洿鏈夋晥鍦板鐞唌ulti gets銆?/p>
銆€ 銆€key鐨勬渶澶ч暱搴︽槸250涓瓧绗︺€傞渶瑕佹敞鎰忕殑鏄紝250鏄痬emcached鏈嶅姟鍣ㄧ鍐呴儴鐨勯檺鍒讹紝濡傛灉鎮ㄤ娇鐢ㄧ殑瀹㈡埛绔敮鎸?key鐨勫墠缂€"鎴栫被浼肩壒鎬э紝 閭ｄ箞key锛堝墠缂€+鍘熷key锛夌殑鏈€澶ч暱搴︽槸鍙互瓒呰繃250涓瓧绗︾殑銆傛垜浠帹鑽愪娇鐢ㄤ娇鐢ㄨ緝鐭殑key锛屽洜涓哄彲浠ヨ妭鐪佸唴瀛樺拰甯﹀銆?/p>
銆€銆€杩囨湡鏃堕棿鏈€澶у彲浠ヨ揪鍒?0澶┿€俶emcached鎶婁紶鍏ョ殑杩囨湡鏃堕棿锛堟椂闂存锛夎В閲婃垚鏃堕棿鐐瑰悗锛屼竴鏃﹀埌浜嗚繖涓椂闂寸偣锛宮emcached灏辨妸item缃负澶辨晥鐘舵€併€傝繖鏄竴涓畝鍗曚絾obscure鐨勬満鍒躲€?/p>
銆€銆€1MB銆傚鏋滀綘鐨勬暟鎹ぇ浜?MB锛屽彲浠ヨ€冭檻鍦ㄥ鎴风鍘嬬缉鎴栨媶鍒嗗埌澶氫釜key涓€?/p>
銆€銆€鍟?..杩欐槸涓€涓ぇ瀹剁粡甯搁棶鐨勯棶棰橈紒
銆€ 銆€Memcache瀹㈡埛绔粎鏍规嵁鍝堝笇绠楁硶鏉ュ喅瀹氬皢鏌愪釜key瀛樺偍鍦ㄥ摢涓妭鐐逛笂锛岃€屼笉鑰冭檻鑺傜偣鐨勫唴瀛樺ぇ灏忋€傚洜姝わ紝鎮ㄥ彲浠ュ湪涓嶅悓鐨勮妭鐐逛笂浣跨敤澶у皬涓嶇瓑鐨勭紦瀛樸€?浣嗘槸涓€鑸兘鏄繖鏍峰仛鐨勶細鎷ユ湁杈冨鍐呭瓨鐨勮妭鐐逛笂鍙互杩愯澶氫釜memcached瀹炰緥锛屾瘡涓疄渚嬩娇鐢ㄧ殑鍐呭瓨璺熷叾浠栬妭鐐逛笂鐨勫疄渚嬬浉鍚屻€?/p>
銆€ 銆€瀹為檯涓婏紝杩欐槸涓€涓紪璇戞椂閫夐」銆傞粯璁や細浣跨敤鍐呴儴鐨剆lab鍒嗛厤鍣ㄣ€傛偍纭疄纭疄搴旇浣跨敤鍐呭缓鐨剆lab鍒嗛厤鍣ㄣ€傛渶鏃╃殑鏃跺€欙紝memcached鍙娇鐢?malloc/free鏉ョ鐞嗗唴瀛樸€傜劧鑰岋紝杩欑鏂瑰紡涓嶈兘涓嶰S鐨勫唴瀛樼鐞嗕互鍓嶅緢濂藉湴宸ヤ綔銆傚弽澶嶅湴malloc/free閫犳垚浜嗗唴瀛樼鐗囷紝OS鏈€缁堣姳璐瑰ぇ閲?鐨勬椂闂村幓鏌ユ壘杩炵画鐨勫唴瀛樺潡鏉ユ弧瓒砿alloc鐨勮姹傦紝鑰屼笉鏄繍琛宮emcached杩涚▼銆傚鏋滄偍涓嶅悓鎰忥紝褰撶劧鍙互浣跨敤malloc锛佸彧鏄笉瑕佸湪閭欢鍒楄〃涓?鎶辨€ㄥ晩:)
銆€銆€褰撶劧锛佸ソ鍚э紝璁╂垜浠潵鏄庣‘涓€涓嬶細
銆€銆€鎵€鏈夌殑琚彂閫佸埌memcached鐨勫崟涓懡浠ゆ槸瀹屽叏鍘熷瓙鐨勩€傚鏋滄偍閽堝鍚屼竴浠芥暟鎹悓鏃跺彂閫佷簡涓€涓猻et鍛戒护鍜屼竴涓猤et鍛戒护锛屽畠浠笉浼氬奖鍝嶅鏂广€傚畠浠皢琚覆琛屽寲銆佸厛鍚庢墽琛屻€傚嵆浣垮湪澶氱嚎绋嬫ā寮忥紝鎵€鏈夌殑鍛戒护閮芥槸鍘熷瓙鐨勶紝闄ら潪绋嬪簭鏈塨ug:)
銆€ 銆€鍛戒护搴忓垪涓嶆槸鍘熷瓙鐨勩€傚鏋滄偍閫氳繃get鍛戒护鑾峰彇浜嗕竴涓猧tem锛屼慨鏀逛簡瀹冿紝鐒跺悗鎯虫妸瀹僺et鍥瀖emcached锛屾垜浠笉淇濊瘉杩欎釜item娌℃湁琚叾浠栬繘 绋嬶紙process锛屾湭蹇呮槸鎿嶄綔绯荤粺涓殑杩涚▼锛夋搷浣滆繃銆傚湪骞跺彂鐨勬儏鍐典笅锛屾偍涔熷彲鑳借鍐欎簡涓€涓鍏朵粬杩涚▼set鐨刬tem銆?/p>