<div>Hi Ken.</div>
<div> </div>
<div>Document size in this application will range from 50 to 200KB. It's the total size of the collection of documents that will be in the tera byte range.</div>
<div> </div>
<div>/Johan<br><br></div>
<div class="gmail_quote">On Dec 18, 2007 10:19 PM, Ken North <<a href="mailto:kennorth@sbcglobal.net">kennorth@sbcglobal.net</a>> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div class="Ih2E3d">Michael Kay wrote:<br><br>>> The database literature is full of alternative techniques.<br></div>>>... three techniques were recognized: record-level locking (which I guess<br>
<div class="Ih2E3d">>>equates to node-level in an XML database), page-level locking, and predicate<br>>>locks. Fine-granularity locking looks good on paper but the benefits can<br>>>often be lost because you spend too much time doing lock acquisition/release
<br></div>>>and deadlock detection ...<br><br>Which is why yet another alternative was developed. Multi-versioning was<br>InterBase's claim to fame and a key reason Borland acquired it for the<br>client-server database wars of the '90s. (InterBase is now Firebird and
<br>Microsoft SQL Server now provides multi-versioning.)<br><br>Clearly we need something more granular than document-level locking,<br>particularly for very large documents.<br><br>The obvious question -- is the capacity to handle terabyte-sized documents
<br>essential for this application?<br>Is there no basis for partitioning the data to permit better concurrency and<br>parallel execution of queries? Oracle XML DB, for example, supports parallel<br>query and a separate, transportable tablespace for XML repositories. Likewise
<br>DB2 and SQL Server have mature technology for parallel execution.<br>
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