Hi, We've looked over the RelsStorage ZODB Blob storage implementation and came to the conclusion that the current use of blob chunks is unnecessary in Oracle when using the cx_Oracle database connector. Not splitting ZODB Blobs into chunks may have performance benefits on the Oracle side (especially on 11g) as Oracle can then use read-ahead more efficiently for the larger BLOBs while streaming these back to the client.
I'll be refactoring the blob support currently found in RelStorage 1.5b2 to just store one blob in one row, using the cx_Oracle LOB.read() and .write() methods, which let you read and write to blobs in chunks to avoid memory overload, and I'll reuse the blob chunk size to determine how much we read / write per iteration. I am currently leaning towards dropping the chunk column in the Oracle schema altogether; it certainly won't hold any other value than integer "0" after my refactor. Any reason to keep it, other than that others whom already are using 1.5b2 on an Oracle database will now have to drop that column again (or set it to a default value of "0" on insert)? Should the code support reading blob chunks still? -- Martijn Pieters _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
