Extensible Storage Engine (ESE), also known as JET Blue, is an ISAM (indexed sequential access method) data storage technology from Microsoft. ESE is the core of Microsoft Exchange Server, Active Directory, Branch Cache, and Windows Search. It's also used by a number of Windows components including Windows Update client and Help and Support Center. Its purpose is to allow applications to store and retrieve data via indexed and sequential access.

ESE provides transacted data update and retrieval. A crash recovery mechanism is provided so that data consistency is maintained even in the event of a system crash. Transactions in ESE are highly concurrent making ESE suitable for server applications. ESE caches data intelligently to ensure high performance access to data. In addition, ESE is lightweight making it suitable for auxiliary applications.

The ESE Runtime (ESENT.DLL) has shipped in every Windows release since Windows 2000, with native x64 version of the ESE runtime shipping with x64 versions of Windows XP and Windows Server 2003. Microsoft Exchange, up to Exchange 2003 shipped with only the 32-bit edition, as it was the only supported platform. With Exchange 2007, it ships with the 64-bit edition.

JET 藍(lán)色最初是由 microsoft 開發(fā)的, 它是Microsoft Access中JET數(shù)據(jù)庫引擎的潛在升級, 但從未在此角色中使用過。相反, 它繼續(xù)被 Exchange 服務(wù)器、活動(dòng)目錄、文件復(fù)制服務(wù)(FRS)、安全配置編輯器、證書服務(wù)、 Windows Internet 名稱服務(wù)(WINS) 和許多其他 Microsoft 服務(wù)使用,應(yīng)用程序和 Windows 組件。 [7] 多年來, 它是 Microsoft 僅使用的專用 api, 但此后已成為任何人都可以使用的已發(fā)布 api。

1989年3月艾倫瑞特加入微軟時(shí), 數(shù)據(jù)訪問引擎 (DAE) 開始工作。在接下來的一年里, 四開發(fā)團(tuán)隊(duì)為艾倫工作, 基本上完成了 ISAM。微軟已經(jīng)有了 BC7 ISAM (JET 紅色), 但開始了數(shù)據(jù)訪問引擎 (DAE) 的努力, 以建立一個(gè)更健壯的數(shù)據(jù)庫引擎作為一個(gè)條目在隨后的新的客戶端-服務(wù)器體系結(jié)構(gòu)領(lǐng)域。1990年春季, BC7 ISAM 和 DAE 團(tuán)隊(duì)加入成為聯(lián)合發(fā)動(dòng)機(jī)技術(shù) (噴氣) 的努力;負(fù)責(zé)生產(chǎn)兩個(gè)引擎的 v1 (JET 紅色) 和 v2 (jet 藍(lán)色), 它將符合相同的 API 規(guī)范 (jet api)。大成噴氣藍(lán)色為以色列的旗子的顏色。BC7 ISAM 成為噴氣機(jī)紅色為旗子的顏色俄國。雖然噴氣藍(lán)和噴氣紅色被寫了到同一 API 規(guī)格, 他們不分享 ISAM 代碼任何。他們都支持一個(gè)共同的查詢處理器, QJET, 后來連同 BC7 ISAM 成為與噴氣紅的同義詞。

JET 藍(lán)色首先在1994年作為 ISAM 在 Windows NT 3.5 中作為 WINS、DHCP 和現(xiàn)在已失效的RPL服務(wù)發(fā)送。它再次作為 Microsoft Exchange 的存儲(chǔ)引擎在1996年再次發(fā)運(yùn)。其他 windows 服務(wù)選擇了 jet 藍(lán)色作為其存儲(chǔ)技術(shù), 到 2000年, windows 的每個(gè)版本都開始以 jet 藍(lán)色裝運(yùn)。JET 藍(lán)色由活動(dòng)目錄使用, 并成為一組特殊的 Windows 代碼 (稱為可信計(jì)算基) (TCB) 的一部分。使用 jet 藍(lán)色的 Microsoft 應(yīng)用程序的數(shù)量繼續(xù)增長, jet 藍(lán)色 API 于2005年發(fā)布, 以方便 Windows 內(nèi)外越來越多的應(yīng)用程序和服務(wù)的使用。

While they share a common lineage, there are vast differences between JET Red and ESE.

• JET Red is a file sharing technology, while ESE is designed to be embedded in a server application, and does not share files.
• JET Red makes best effort file recovery, while ESE has write ahead logging and snapshot isolation for guaranteed crash recovery.
• JET Red before version 4.0 supports only page level locking, while ESE and JET Red version 4.0 supports record level locking.
• JET Red supports a wide variety of query interfaces, including ODBC and OLE DB. ESE does not ship with a query engine but instead relies on applications to write their own queries as C ISAM code.
• JET Red has a maximum database file size of 2 GiB, while ESE has a maximum database file size of 8 TiB with 4 KiB pages, and 16 TiB with 8 KiB pages.