{"id":41105,"date":"2026-08-27T10:14:05","date_gmt":"2026-08-27T07:14:05","guid":{"rendered":"https:\/\/profelis.com.tr\/?p=41105"},"modified":"2026-08-27T10:24:20","modified_gmt":"2026-08-27T07:24:20","slug":"felaket-kurtarma-tatbikati-nasil-soruna-donusebilir-postgresql-restore-surecinde-sessiz-kilitlenme-bug-19490","status":"publish","type":"post","link":"https:\/\/profelis.com.tr\/en\/2026\/08\/27\/felaket-kurtarma-tatbikati-nasil-soruna-donusebilir-postgresql-restore-surecinde-sessiz-kilitlenme-bug-19490\/","title":{"rendered":"Felaket Kurtarma Tatbikat\u0131 Nas\u0131l Soruna D\u00f6n\u00fc\u015febilir? PostgreSQL Restore S\u00fcrecinde Sessiz Kilitlenme (Bug #19490)"},"content":{"rendered":"
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Sessizce Bekleyen Tehlike: Her \u015eey Yolunda G\u00f6r\u00fcn\u00fcrken...<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Sistem y\u00f6neticileri i\u00e7in felaket kurtarma (Disaster Recovery – DR) testleri genellikle rutin ve tahmin edilebilir s\u00fcre\u00e7lerdir. En az\u0131ndan \u00f6yle san\u0131yor olabilirsiniz. \u00dcretim (production) ortam\u0131n\u0131z\u0131n yede\u011fini ald\u0131n\u0131z, test sunucunuza aktard\u0131n\u0131z. Base backup sorunsuz \u015fekilde a\u00e7\u0131ld\u0131, her \u015fey yolunda g\u00f6z\u00fck\u00fcyor. S\u0131ra, yedek al\u0131nd\u0131ktan sonraki i\u015flemleri veritaban\u0131na i\u015fleyecek olan WAL (Write-Ahead Log) dosyalar\u0131n\u0131n uygulanmas\u0131na (replay) geldi.<\/span><\/p>

Loglar\u0131 izliyorsunuz; WAL dosyalar\u0131 birer birer ar\u015fivden \u00e7ekiliyor, i\u015fleniyor… Derken aniden her \u015fey duruyor.<\/span><\/p>

Ba\u015fta bunun b\u00fcy\u00fck transaction (i\u015flem) blo\u011fu oldu\u011funu ve sistemin onu diske yazmakla me\u015fgul oldu\u011funu d\u00fc\u015f\u00fcnebilirsiniz. Be\u015f dakika ge\u00e7er, on dakika ge\u00e7er, yar\u0131m saat olur… Sunucunun kaynak kullan\u0131m\u0131na bakars\u0131n\u0131z; i\u015flemci (CPU) rahat, disk I\/O neredeyse s\u0131f\u0131r. Ancak kurtarma (restore) s\u00fcreci bitmez, veritaban\u0131 bir t\u00fcrl\u00fc aya\u011fa kalk\u0131p “sistemi kullan\u0131ma a\u00e7t\u0131m” mesaj\u0131n\u0131 (database system is ready to accept connections) vermez. \u0130\u015flenmeyi bekleyen gigabaytlarca WAL dosyas\u0131 kap\u0131da bekler, ama i\u00e7eride kimse onlara dokunmuyordur. \u0130\u015fin en sinir bozucu taraf\u0131 ise hata loglar\u0131n\u0131n (error log) tertemiz olmas\u0131d\u0131r. Hi\u00e7bir \u00e7\u00f6kme, hi\u00e7bir hata mesaj\u0131 yoktur; sadece sessizlik ve donup kalm\u0131\u015f startup (ba\u015flatma) s\u00fcreci vard\u0131r.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"\"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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As\u0131l Sorun Kendisi: MultiXactOffsetSLRU<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Madem loglar size bir \u015fey s\u00f6ylemiyor, o halde i\u015fletim sistemi seviyesine inelim. Ask\u0131da kalan PostgreSQL startup s\u00fcrecinin (PID) neyi bekledi\u011fini inceledi\u011finizde \u015fu manzarayla kar\u015f\u0131la\u015fabilirsiniz: S\u00fcre\u00e7 bir <\/span>futex_wait<\/span> (i\u015fletim sistemi seviyesinde kilit bekleme) durumuna d\u00fc\u015fm\u00fc\u015ft\u00fcr. PostgreSQL’in kendi i\u00e7 izleme ara\u00e7lar\u0131yla (veya hot standby a\u00e7\u0131ksa pg_stat_activity<\/span> \u00fczerinden) bakt\u0131\u011f\u0131n\u0131zda, tak\u0131l\u0131 kald\u0131\u011f\u0131 bekleme olay\u0131n\u0131 (wait event) g\u00f6r\u00fcrs\u00fcn\u00fcz:<\/span><\/p>

LWLock: MultiXactOffsetSLRU<\/b><\/span><\/p>

Sistem, MultiXact i\u015flemi i\u00e7in kilit talep etmi\u015f ama bu kilit sonsuz d\u00f6ng\u00fcde kilitlenip kalm\u0131\u015ft\u0131r (Deadlock). Veri okunam\u0131yor, yaz\u0131lam\u0131yor ve do\u011fal olarak kalan WAL dosyalar\u0131 i\u015flenemiyordur.<\/span><\/p>

Olay\u0131n k\u00f6k nedenini ara\u015ft\u0131r\u0131rken, PostgreSQL toplulu\u011funun hata kay\u0131tlar\u0131nda (pgsql-bugs) gezinirseniz tam da bu senaryoyu anlatan <\/span>Bug #19490<\/b><\/span> ile y\u00fczle\u015febilirsiniz.<\/span><\/p>

Peki bu kilitlenme neden durup dururken ba\u015f\u0131n\u0131za geldi? Cevap, masumane g\u00f6r\u00fcnen “versiyon” farkl\u0131l\u0131\u011f\u0131nda gizlidir. \u00d6rne\u011fin \u00fcretim sunucunuz <\/span>16.8<\/b><\/span> s\u00fcr\u00fcm\u00fcnde \u00e7al\u0131\u015f\u0131rken, \u00fczerine restore testini yapt\u0131\u011f\u0131n\u0131z yedek sunucunuz yeni kuruldu\u011fu i\u00e7in <\/span>16.14<\/b><\/span> s\u00fcr\u00fcm\u00fcne sahip olabilir. “Nas\u0131l olsa minor (alt) s\u00fcr\u00fcm fark\u0131, geriye d\u00f6n\u00fck uyumludur” diye d\u00fc\u015f\u00fcnebilirsiniz. Ancak PostgreSQL 16.12’de <\/strong><\/span>SimpleLruWriteAll() fonksiyonuna eklenen kod de\u011fi\u015fikli\u011fi, alt s\u00fcr\u00fcmler aras\u0131 WAL replay i\u015flemlerinde bu gizli deadlock hatas\u0131n\u0131 tetiklemektedir.<\/strong><\/p>

E\u011fer siz de restore operasyonunun ortas\u0131nda WAL dosyalar\u0131n\u0131n aniden i\u015flemeyi kesti\u011fi, sistemin sessizce dondu\u011fu sorunu ya\u015farsan\u0131z, yaln\u0131z de\u011filsiniz.<\/strong> Gelin bu a\u00e7mazdan nas\u0131l kurtulabilece\u011finize ve veritaban\u0131n\u0131 nas\u0131l aya\u011fa kald\u0131rabilece\u011finize bakal\u0131m.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Ge\u00e7ici \u00c7\u00f6z\u00fcm Aray\u0131\u015f\u0131: Versiyon D\u00fc\u015f\u00fcrmek (Downgrade)<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Sorunu tespit ettikten sonra ilk akla gelen, test sunucusundaki PostgreSQL versiyonunu production ile ayn\u0131 seviyeye, yani 16.8’e (veya hatan\u0131n hen\u00fcz olmad\u0131\u011f\u0131 16.11’e) \u00e7ekmek olabilir. Veri dizinine (data directory) dokunmadan sadece binary dosyalar\u0131n\u0131 d\u00fc\u015f\u00fcrmek teorik olarak m\u00fcmk\u00fcnd\u00fcr. Ancak paket d\u00fc\u015f\u00fcrmekle u\u011fra\u015fmak, i\u015fletim sistemi ba\u011f\u0131ml\u0131l\u0131klar\u0131n\u0131 \u00e7\u00f6zmeye \u00e7al\u0131\u015fmak isteyece\u011finiz en son \u015feydir. Size \u00e7ok daha temiz ve kal\u0131c\u0131 \u00e7\u00f6z\u00fcm laz\u0131md\u0131r.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Kurtar\u0131c\u0131 S\u00fcre\u00e7: PostgreSQL 16.15<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Neyse ki PostgreSQL toplulu\u011fu bu hatan\u0131n (Bug #19490) fark\u0131na varm\u0131\u015f ve m\u00fcdahale etmi\u015ftir. <\/span>13 A\u011fustos 2026<\/b><\/span> tarihinde yay\u0131nlanan <\/span>PostgreSQL 16.15<\/b><\/span> s\u00fcr\u00fcm\u00fc, tam da bu dertten muzdarip olanlar i\u00e7in \u00e7\u00f6z\u00fcm olmu\u015ftur. S\u00fcr\u00fcm notlar\u0131 incelendi\u011finde, WAL replay (uygulama) s\u0131ras\u0131nda SLRU kilitlerinde ya\u015fanan o k\u00f6rd\u00fc\u011f\u00fcm\u00fcn \u00e7\u00f6z\u00fcld\u00fc\u011f\u00fc g\u00f6r\u00fclmektedir.<\/strong><\/span><\/p>

Yapman\u0131z gereken tek \u015fey sunucuyu ileriye ta\u015f\u0131makt\u0131r. Bu “minor” (alt) s\u00fcr\u00fcm g\u00fcncellemesi oldu\u011fu i\u00e7in veritaban\u0131 dosyalar\u0131yla veya karma\u015f\u0131k g\u00f6\u00e7 senaryolar\u0131yla u\u011fra\u015fman\u0131za gerek yoktur:<\/span><\/p>

  1. Test sunucusundaki kilitlenmi\u015f PostgreSQL servisini durdurun.<\/span><\/li>
  2. \u0130\u015fletim sisteminizin paket y\u00f6neticisi (apt\/yum vb.) \u00fczerinden <\/span>postgresql-16<\/span> paketini g\u00fcncelleyerek <\/span>16.15<\/b><\/span> s\u00fcr\u00fcm\u00fcne \u00e7ekin.<\/span><\/li>
  3. Servisi yeniden ba\u015flat\u0131n.<\/span><\/li><\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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    Suskunlu\u011fun Bozulmas\u0131 ve Mutlu Son<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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    PostgreSQL servisini ba\u015flatt\u0131ktan sonra log dosyas\u0131n\u0131 g\u00f6zlemleyin. Ve o \u00e7\u00f6z\u00fcm an\u0131 gelecektir… Saatlerdir dokunulmadan bekleyen gigabaytlarca WAL dosyas\u0131, saniyeler i\u00e7inde i\u015flenmeye ba\u015flanacakt\u0131r. <\/span>pg_stat_slru<\/span> s\u0131f\u0131rlanacak ve bekleme olaylar\u0131 (wait events) tamamen normale d\u00f6necektir. Kilitlenme olmayacak, tak\u0131lma ya\u015fanmayacakt\u0131r. Sadece birka\u00e7 dakika i\u00e7inde log dosyas\u0131nda beklenen sat\u0131r\u0131 g\u00f6receksiniz:<\/span><\/p>

    LOG: database system is ready to accept connections<\/span><\/p>

    Veritaban\u0131n\u0131z sa\u011fl\u0131kl\u0131 \u015fekilde aya\u011fa kalkacak, tam veri tutarl\u0131l\u0131\u011f\u0131 (consistency) sa\u011flanacak ve stresli ba\u015flayan restore testiniz ba\u015far\u0131yla sonu\u00e7lanacakt\u0131r.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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    \u00c7\u0131kar\u0131lmas\u0131 Gereken Dersler (Best Practices)<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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    Bu tarz restore testleri, veritaban\u0131 y\u00f6netimi hakk\u0131nda alt\u0131n de\u011ferinde birka\u00e7 kural\u0131 hat\u0131rlat\u0131r:<\/span><\/p>

    1. Minor S\u00fcr\u00fcmleri Hafife Almay\u0131n:<\/b> “16.x ile 16.y nas\u0131l olsa ayn\u0131d\u0131r”<\/span><\/i> demeyin. Veritaban\u0131 d\u00fcnyas\u0131nda k\u00fc\u00e7\u00fck kod de\u011fi\u015fiklikleri, \u00f6zellikle WAL replay ve SLRU gibi alt seviye \u00e7ekirdek mekanizmalarda \u00f6ng\u00f6r\u00fclemeyen b\u00fcy\u00fck etkilere yol a\u00e7abilir.<\/span><\/li>
    2. Versiyon Senkronizasyonu \u015eart:<\/b> Restore testleri yapt\u0131\u011f\u0131n\u0131z veya Felaket Kurtarma (DR) olarak bekletti\u011finiz sunucular\u0131n versiyonlar\u0131n\u0131, \u00fcretim (production) sunucular\u0131n\u0131zla <\/span>birebir ayn\u0131 minor versiyonda<\/b> tutmaya \u00f6zen g\u00f6sterin.<\/span><\/li>
    3. G\u00fcncel Kal\u0131n:<\/b> E\u011fer versiyon fark\u0131 ka\u00e7\u0131n\u0131lmazsa veya yepyeni sunucu kuruyorsan\u0131z, her zaman PostgreSQL toplulu\u011funun duyurdu\u011fu bilinen en son kararl\u0131 s\u00fcr\u00fcme (bizim durumumuzda 16.15) ge\u00e7in.<\/span><\/li><\/ol>

      E\u011fer sizin de restore i\u015fleminiz sebepsiz yere donuyor ve loglar size hi\u00e7bir \u015fey s\u00f6ylemiyorsa, belki de arka planda sessiz sedas\u0131z bekleyen <\/span><\/span>MultiXactOffsetSLRU<\/span> kilidi<\/span> vard\u0131r. \u00c7\u00f6z\u00fcm \u00e7ok uzakta de\u011fil; sunucunuzu <\/span>16.15’e g\u00fcncelleyin<\/b><\/span> ve arkan\u0131za yaslan\u0131p loglar\u0131n ak\u0131\u015f\u0131n\u0131 izleyin.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

      PostgreSQL restore s\u00fcrecindeki sessiz kilitlenmenin nedenini, Bug #19490\u2019\u0131 ve PostgreSQL 16.15 ile gelen \u00e7\u00f6z\u00fcm\u00fc teknik ayr\u0131nt\u0131lar\u0131yla inceleyin.<\/p>","protected":false},"author":16,"featured_media":41111,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[45,75,129],"tags":[60,50],"class_list":["post-41105","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-yazi","category-postgresql","category-veritabani","tag-postgresql","tag-veritabani"],"_links":{"self":[{"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/posts\/41105","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/comments?post=41105"}],"version-history":[{"count":15,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/posts\/41105\/revisions"}],"predecessor-version":[{"id":41127,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/posts\/41105\/revisions\/41127"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/media\/41111"}],"wp:attachment":[{"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/media?parent=41105"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/categories?post=41105"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/profelis.com.tr\/en\/wp-json\/wp\/v2\/tags?post=41105"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}