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https://issues.apache.org/jira/browse/SOLR-14413?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17182060#comment-17182060
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John Gallagher commented on SOLR-14413:
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Thanks [~mdrob] for reviewing!
I added new documentation for omitHeader, advising against omitting when using
parameters that can lead to partial results, because the header flag informs
the interpretation of the result values.
!image-2020-08-21-14-18-36-229.png|width=558,height=180!
I updated timeAllowed documentation as well.
I incorporated [~bvd]'s test idea of generating a result set, running it to
completion, and confirming all documents were found in the correct order, while
also asserting that at least one partialResults event occurred.
I have generated a new patch, SOLR-14413-jg-update2.patch, and updated my PR:
[https://github.com/apache/lucene-solr/pull/1436]
John
> allow timeAllowed and cursorMark parameters
> -------------------------------------------
>
> Key: SOLR-14413
> URL: https://issues.apache.org/jira/browse/SOLR-14413
> Project: Solr
> Issue Type: Improvement
> Components: search
> Reporter: John Gallagher
> Priority: Minor
> Attachments: SOLR-14413-bram.patch, SOLR-14413-jg-update1.patch,
> SOLR-14413.patch, image-2020-08-18-16-56-41-736.png,
> image-2020-08-18-16-56-59-178.png, image-2020-08-21-14-18-36-229.png,
> timeallowed_cursormarks_results.txt
>
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> Ever since cursorMarks were introduced in SOLR-5463 in 2014, cursorMark and
> timeAllowed parameters were not allowed in combination ("Can not search using
> both cursorMark and timeAllowed")
> , from [QueryComponent.java|#L359]]:
>
> {code:java}
>
> if (null != rb.getCursorMark() && 0 < timeAllowed) {
> // fundamentally incompatible
> throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, "Can not
> search using both " + CursorMarkParams.CURSOR_MARK_PARAM + " and " +
> CommonParams.TIME_ALLOWED);
> } {code}
> While theoretically impure to use them in combination, it is often desirable
> to support cursormarks-style deep paging and attempt to protect Solr nodes
> from runaway queries using timeAllowed, in the hopes that most of the time,
> the query completes in the allotted time, and there is no conflict.
>
> However if the query takes too long, it may be preferable to end the query
> and protect the Solr node and provide the user with a somewhat inaccurate
> sorted list. As noted in SOLR-6930, SOLR-5986 and others, timeAllowed is
> frequently used to prevent runaway load. In fact, cursorMark and
> shards.tolerant are allowed in combination, so any argument in favor of
> purity would be a bit muddied in my opinion.
>
> This was discussed once in the mailing list that I can find:
> [https://mail-archives.apache.org/mod_mbox/lucene-solr-user/201506.mbox/%3c5591740b.4080...@elyograg.org%3E]
> It did not look like there was strong support for preventing the combination.
>
> I have tested cursorMark and timeAllowed combination together, and even when
> partial results are returned because the timeAllowed is exceeded, the
> cursorMark response value is still valid and reasonable.
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