An Injection with Tree Awareness Adding Staircase Join to PostgreSQL
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چکیده
The XPath accelerator (“pre/post numbering”) has proven to be an efficient encoding to losslessly store XML data in relational databases. Conventional RDBMSs, however, remain ignorant of interesting properties of the encoded tree data, and make thus no or poor use of these properties. At VLDB 2003 we devised a new join algorithm, staircase join, that encapsulates tree-specific knowledge and can turn SQL systems into highly efficient XPath processors. This demonstration delivers the promise we have made at VLDB 2003: a notion of tree-awareness can be injected into a conventional disk-based RDBMS kernel in terms of staircase join. We feature a sideby-side comparison of both, an original and a staircase join-enhanced instance of PostgreSQL. The required changes to PostgreSQL were local. The achieved effect, however, is significant: the demonstration proves that this injection of tree awareness makes PostgreSQL a high-performance XPath processor that closely adheres to the XPath semantics. Accelerating XPath Location Steps ➜ a b c d e f g h i j 0 1 2 3 4 5 6 7 8 9 9 3 2 0 1 8 4 7 5 6 ➜ •
منابع مشابه
An Injection of Tree Awareness: Adding Staircase Join to PostgreSQL
The syntactic wellformedness constraints of XML (opening and closing tags nest properly) imply that XML processors face the challenge to efficiently handle data that takes the shape of ordered, unranked trees. Although RDBMSs have originally been designed to manage table-shaped data, we propose their use as XML and XPath processors. In our setup, the database system employs a relational XML doc...
متن کاملEnhancing the Tree Awareness of a Relational DBMS: Adding Staircase Join to PostgreSQL
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متن کاملStaircase Join: Teach a relational DBMS to Watch its (Axis) Steps. 2003
Relational query processors derive much of their effectiveness from the awareness of specific table properties like sort order, size, or absence of duplicate tuples. This text applies (and adapts) this successful principle to database-supported XML and XPath processing: the relational system is made tree aware, i.e., tree properties like subtree size, intersection of paths, inclusion or disjoin...
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تاریخ انتشار 2004