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https://issues.apache.org/jira/browse/SOLR-11240?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Toke Eskildsen updated SOLR-11240:
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Attachment: SOLR-11240.patch
Patch for master. Running {{ant test}} reported failing unit-tests for Cdcr &
Cloud, but those areas are pretty far from the patch and the tests also fails
when running without the patch.
Note the addition of the slow {{testTriggerUnInvertLimit}} in
{{TestDocTermOrds}}. It takes about 10-15 seconds to run on a modern machine
with SSD. I find that to be problematic, but I don't know any way to very
quickly build an index with high enough term-cardinality to reach the old limit.
Barring errors, the fix should be complete and potential back-porting to 7x (or
6) seems trivial. I invite anyone to review the patch.
> Raise UnInvertedField internal limit
> ------------------------------------
>
> Key: SOLR-11240
> URL: https://issues.apache.org/jira/browse/SOLR-11240
> Project: Solr
> Issue Type: Improvement
> Security Level: Public(Default Security Level. Issues are Public)
> Components: faceting
> Affects Versions: 5.5.4, 6.6
> Reporter: Toke Eskildsen
> Assignee: Toke Eskildsen
> Priority: Minor
> Labels: easyfix
> Fix For: master (8.0)
>
> Attachments: SOLR-11240.patch
>
>
> {{UnInvertedField}} has via {{DocTermOrds}} an internal limitation of 2^24
> bytes for byte-arrays holding term ordinals. For String faceting on
> high-cardinality Text fields, this can trigger the exception with "Too many
> values for UnInvertedField". A search for that phrase shows that the
> exception is encountered in the wild.
> The limitation is due to the packing being a combination of values and
> pointers: If the values (term ordinals) for a given document-ID can fit in an
> integer, they are stored directly. If the value of the first 8 bits in the
> integer is 1, it signals that the following 3 bytes (24 bits) is a pointer
> into a byte-array, limiting the array-size to 16M (2^24).
> Solution: Due to the values being packed at vInts, bit 31 (the last bit) of
> the integer will never be 1 if the integer contains values. This means that
> this bit it can be used for signalling whether or not the preceding bits
> should be parsed as values or a pointer. The effective pointer size is thus
> 2^31, which matches the array-length limit in Java. Changing the signalling
> mechanism does not affect space requirements and should not affect
> performance.
> Note that this is only a 100-fold increase ever the 2^24 limit, not an
> elimination: Performing uninverted Text field faceting on 100M documents with
> 5K terms each will still raise an exception.
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