{"id":36650,"date":"2019-10-31T22:12:54","date_gmt":"2019-10-31T19:12:54","guid":{"rendered":"https:\/\/prohoster.info\/blog\/tranzaktsii-v-globalah-intersystems-iris\/"},"modified":"2019-10-31T22:12:54","modified_gmt":"2019-10-31T19:12:54","slug":"tranzaktsii-v-globalah-intersystems-iris","status":"publish","type":"post","link":"https:\/\/prohoster.info\/lv\/blog\/administrirovanie\/tranzaktsii-v-globalah-intersystems-iris","title":{"rendered":"Transakcijas glob\u0101los InterSystems IRIS","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\"TransakcijasInterSystems IRIS DB atbalsta interesantus datu glab\u0101\u0161anas risin\u0101jumus \u2014 glob\u0101los. Paties\u012bb\u0101 tas ir daudzl\u012bme\u0146u atsl\u0113gu kopums ar da\u017e\u0101d\u0101m papildu iesp\u0113j\u0101m, piem\u0113ram, dar\u012bjumiem, \u0101tr\u0101m funkcij\u0101m datu koku apgait\u0113, blo\u0137\u0113\u0161anu un savu ObjectScript valodu.<\/p>\n

Pla\u0161\u0101k par glob\u0101liem rakstu cikl\u0101 \"Glob\u0101li \u2014 datu glab\u0101\u0161anas zobeni-k\u013cadences\":<\/p>\n

Koki. 1. da\u013ca<\/a><\/noindex>
\nKoki. 2. da\u013ca<\/a><\/noindex>
\nRetin\u0101ti mas\u012bvi. 3. da\u013ca<\/a><\/noindex><\/p>\n

Mani interes\u0113ja, k\u0101 tiek \u012bstenoti dar\u012bjumi glob\u0101los, k\u0101das ir to \u012bpatn\u012bbas. Jo t\u0101 ir piln\u012bgi cita datu glab\u0101\u0161anas strukt\u016bra nek\u0101 visiem ierast\u0101s tabulas. Kaut kas daudz zem\u0101ka l\u012bme\u0146a.
\n<\/a><\/noindex>
\nK\u0101 zin\u0101ms, no rel\u0101ciju datu b\u0101zu teorijas laba dar\u012bjumu \u012bsteno\u0161ana j\u0101atbilst pras\u012bb\u0101m ACID<\/a><\/noindex>:<\/p>\n

A \u2014 Atomiskums.<\/b> Visas izmai\u0146as, kas veiktas dar\u012bjuma laik\u0101, tiek ierakst\u012btas vai nekas netiek ierakst\u012bts.<\/p>\n

S \u2014 Saska\u0146ot\u012bba.<\/b> P\u0113c dar\u012bjuma pabeig\u0161anas datu b\u0101zes lo\u0123iskajam st\u0101voklim j\u0101b\u016bt iek\u0161\u0113ji konsekventam. Da\u013c\u0113ji \u0161\u012b pras\u012bba attiecas uz programm\u0113t\u0101ju, bet SQL datu b\u0101z\u0113m t\u0101 attiecas ar\u012b uz \u0101r\u0113j\u0101m atsl\u0113g\u0101m.<\/p>\n

I \u2014 Izol\u0101cija.<\/b> Vienlaikus notieko\u0161iem dar\u012bjumiem nedr\u012bkst ietekm\u0113t cits citu.<\/p>\n

D \u2014 Ilgtsp\u0113ja.<\/b> P\u0113c veiksm\u012bgas dar\u012bjuma pabeig\u0161anas probl\u0113m\u0101m apak\u0161\u0113j\u0101s l\u012bme\u0146os (piem\u0113ram, baro\u0161anas trauc\u0113jumi) nedr\u012bkst ietekm\u0113t ar dar\u012bjumu main\u012btajiem datiem.<\/p>\n

Glob\u0101li ir norel\u0101ciju datu strukt\u016bras. T\u0101s tika izstr\u0101d\u0101tas super \u0101trai darb\u012bbai uz \u013coti ierobe\u017eota dzel\u017eiem. Apskat\u012bsim dar\u012bjumu \u012bsteno\u0161anu glob\u0101los ar ofici\u0101lo IRIS docker att\u0113lu<\/a><\/noindex>.<\/p>\n

Lai atbalst\u012btu dar\u012bjumus IRIS, tiek izmantotas komandas: TSTART<\/a><\/noindex>, TCOMMIT<\/a><\/noindex>, TROLLBACK<\/a><\/noindex>.<\/p>\n

1. Atomiskums<\/h2>\n

\nVisviegl\u0101k ir p\u0101rbaud\u012bt atomiskumu. P\u0101rbaud\u0101m datu b\u0101zes konsol\u0113.<\/p>\n

Kill ^a\nTSTART\nSet ^a(1) = 1\nSet ^a(2) = 2\nSet ^a(3) = 3\nTCOMMIT<\/code><\/pre>\n
\nP\u0113c tam izdar\u0101m secin\u0101jumu:<\/p>\n
Write ^a(1), \u201c \u201d, ^a(2), \u201c \u201d, ^a(3)<\/code><\/pre>\n
\nIeg\u016bsim:<\/p>\n
1 2 3<\/code><\/pre>\n
\nViss ir k\u0101rt\u012bb\u0101. Atomiskums ir saglab\u0101ts: visas izmai\u0146as ir ierakst\u012btas.<\/p>\n
Apgr\u016btin\u0101sim uzdevumu, ievie\u0161ot k\u013c\u016bdu un skat\u012bsim, k\u0101 saglab\u0101sies dar\u012bjums, da\u013c\u0113ji vai pavisam n\u0113.<\/p>\n
V\u0113lreiz p\u0101rbaud\u012bsim atomiskumu:<\/p>\n
Kill ^A\nTSTART\nSet ^a(1) = 1\nSet ^a(2) = 2\nSet ^a(3) = 3<\/code><\/pre>\n
\nP\u0113c tam piespied\u012bsim apst\u0101ties konteineram, palaid\u012bsim un paskat\u012bsimies. <\/p>\n
docker kill my-iris<\/code><\/pre>\n
\n\u0160\u012b komanda ir praktiski ekvivalenta piespiedu izsl\u0113g\u0161anai, jo t\u0101 nos\u016bta t\u016bl\u012bt\u0113ju procesa SIGKILL aptur\u0113\u0161anas sign\u0101lu.<\/p>\n
Vai dar\u012bjums varb\u016bt ir saglab\u0101jies da\u013c\u0113ji?<\/p>\n
WRITE ^a(1), ^a(2), ^a(3)\n^\n ^a(1)<\/code><\/pre>\n
\n \u2014 N\u0113, tas nav saglab\u0101jies.<\/p>\n
Izm\u0113\u0123in\u0101sim atjauno\u0161anas komandu:<\/p>\n
Kill ^A\nTSTART\nSet ^a(1) = 1\nSet ^a(2) = 2\nSet ^a(3) = 3\nTROLLBACK\n\nWRITE ^a(1), ^a(2), ^a(3)\n^\n ^a(1)<\/code><\/pre>\n
\nAr\u012b nekas nav saglab\u0101jies.<\/p>\n
2. Saska\u0146ot\u012bba<\/h2>\n
\nT\u0101 k\u0101 globaliz\u0101cijas datub\u0101z\u0113s atsl\u0113gas tiek veidotas ar\u012b uz globaliz\u0101cij\u0101m (atg\u0101dinu, ka globaliz\u0101cija ir zem\u0101ka l\u012bme\u0146a datu glab\u0101\u0161anas strukt\u016bra nek\u0101 rel\u0101ciju tabula), lai izpild\u012btu saska\u0146ot\u012bbas pras\u012bbas, atsl\u0113gas izmai\u0146ai ir j\u0101b\u016bt iek\u013cautai taj\u0101 pa\u0161\u0101 dar\u012bjum\u0101 k\u0101 globaliz\u0101cijas izmai\u0146\u0101m.<\/p>\n
Piem\u0113ram, mums ir globaliz\u0101cija ^person, kur\u0101 m\u0113s glab\u0101jam personas un k\u0101 atsl\u0113gu izmantojam INN.<\/p>\n
^person(1234567, \u2018firstname\u2019) = \u2018Sergejs\u2019\n^person(1234567, \u2018lastname\u2019) = \u2018Kamenevs\u2019\n^person(1234567, \u2018phone\u2019) = \u2018+74995555555\n...<\/code><\/pre>\n
\nLai veiktu \u0101tru mekl\u0113\u0161anu p\u0113c uzv\u0101rda un v\u0101rda, m\u0113s izveidoj\u0101m atsl\u0113gu ^index.<\/p>\n
^index(\u2018Kamenevs\u2019, \u2018Sergejs\u2019, 1234567) = 1<\/code><\/pre>\n
\nLai datub\u0101ze b\u016btu saska\u0146ota, mums j\u0101ievieto persona \u0161\u0101di:<\/p>\n
TSTART\n^person(1234567, \u2018firstname\u2019) = \u2018Sergejs\u2019\n^person(1234567, \u2018lastname\u2019) = \u2018Kamenevs\u2019\n^person(1234567, \u2018phone\u2019) = \u2018+74995555555\n^index(\u2018Kamenevs\u2019, \u2018Sergejs\u2019, 1234567) = 1\nTCOMMIT<\/code><\/pre>\n
\nAtbilsto\u0161i, izdz\u0113\u0161ot, mums ar\u012b ir j\u0101izmanto dar\u012bjums:<\/p>\n
TSTART\nKill ^person(1234567)\nZKill ^index(\u2018Kamenevs\u2019, \u2018Sergejs\u2019, 1234567)\nTCOMMIT<\/code><\/pre>\n
\nCit\u0101di sakot, saska\u0146ot\u012bbas pras\u012bbu izpilde gultas piln\u012bb\u0101 uz programmat\u016bras izstr\u0101d\u0101t\u0101ja pleciem. Bet run\u0101jot par globaliz\u0101cij\u0101m, tas ir dabiski, \u0146emot v\u0113r\u0101 to zemo l\u012bme\u0146a dabu.<\/p>\n
3. Izol\u0113t\u012bba<\/h2>\n
\n\u0160eit s\u0101kas sare\u017e\u0123\u012bjumi. Daudzi lietot\u0101ji vienlaikus str\u0101d\u0101 ar to pa\u0161u datub\u0101zi, maina tos pa\u0161us datus.<\/p>\n
Situ\u0101cija ir sal\u012bdzin\u0101ma ar to, ka daudzi lietot\u0101ji vienlaikus str\u0101d\u0101 pie viena un t\u0101 pa\u0161a koda repozit\u0101ra un m\u0113\u0123ina vienlaikus taj\u0101 veikt izmai\u0146as daudzos failos.<\/p>\n
Datub\u0101zei ir j\u0101risina viss \u0161is re\u0101laj\u0101 laik\u0101. \u0145emot v\u0113r\u0101, ka nopietn\u0101s komp\u0101nij\u0101s ir pat speci\u0101la persona, kas atbild par versiju kontroles (par zaru apvieno\u0161anu, konfliktu risin\u0101\u0161anu utt.), un datub\u0101zei tas viss j\u0101risina re\u0101laj\u0101 laik\u0101, k\u013c\u016bst ac\u012bmredzama uzdevuma sare\u017e\u0123\u012bt\u012bba un pareiz\u0101 datub\u0101zes un t\u0101s apkopes koda projekt\u0113\u0161ana.<\/p>\n
Datu b\u0101ze nevar saprast, k\u0101 lietot\u0101ji r\u012bkojas, lai nov\u0113rstu konfliktus, ja vi\u0146i str\u0101d\u0101 ar tiem pa\u0161iem datiem. T\u0101 var tikai atcelt vienu dar\u012bjumu, kas ir pretrun\u0101 ar citu, vai veikt tos sec\u012bgi.<\/p>\n
V\u0113l viena probl\u0113ma ir t\u0101, ka dar\u012bjuma izpildes laik\u0101 (pirms apstiprin\u0101\u0161anas) datu b\u0101zes st\u0101voklis var b\u016bt nesaska\u0146ots, t\u0101p\u0113c ir v\u0113lams, lai citiem dar\u012bjumiem neb\u016btu piek\u013cuves nesaska\u0146otajam datu b\u0101zes st\u0101voklim, ko rel\u0101ciju datu b\u0101z\u0113s var sasniegt daudziem veidiem: snapshotu izveide, vair\u0101ku versiju rindi\u0146as utt.<\/p>\n
Veicot dar\u012bjumus paral\u0113li, ir svar\u012bgi, lai tie netrauc\u0113tu viens otram. Tas ir izol\u0101cijas \u012bpa\u0161ums.<\/p>\n
SQL nosaka 4 izol\u0101cijas l\u012bme\u0146us:<\/p>\n