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https://issues.apache.org/jira/browse/OAK-1941?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Reschke updated OAK-1941:
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Attachment: with-modified-index.diff
a change that creates an index on _modified; right now it's not clear whether
this actually improves performance
> RDB: decide on table layout
> ---------------------------
>
> Key: OAK-1941
> URL: https://issues.apache.org/jira/browse/OAK-1941
> Project: Jackrabbit Oak
> Issue Type: Sub-task
> Components: rdbmk
> Reporter: Julian Reschke
> Assignee: Julian Reschke
> Fix For: 1.2
>
> Attachments: OAK-1941-cmodcount.diff, utf8measure.diff,
> with-modified-index.diff, with-modified-index.diff
>
>
> The current approach is to serialize the Document using JSON, and then to
> store either (a) the full JSON in a VARCHAR column, or, if that column isn't
> wide enough, (b) to store it in a BLOB (optionally gzipped).
> For debugging purposes, the inline VARCHAR always gets populated with the
> start of the JSON serialization.
> However, with Oracle we are limited to 4000 bytes (which may be way less
> characters due to non-ASCII overhead), so many document instances will use
> what was initially thought to be the exception case.
> Questions:
> 1) Do we stick with JSON or do we attempt a different serialization? It might
> make sense both wrt to length and performance. There might be also some code
> to borrow from the off-heap serialization code.
> 2) Do we get rid of the "dual" strategy, and just always use the BLOB? The
> indirection might make things more expensive, but then the total column width
> would drop considerably. -- How can we do good benchmarks on this?
> (This all assumes that we stick with a model where all code is the same
> between database types, except for the DDL statements; of course it's also
> conceivable add more vendor-specific special cases into the Java code)
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