[jira] [Created] (SOLR-10159) DBQ, where query is based on updated value, reordered with the update doesn't work

["Ishan Chattopadhyaya (JIRA)" <ji...@apache.org>]

Ishan Chattopadhyaya created SOLR-10159:
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             Summary: DBQ, where query is based on updated value, reordered with the update doesn't work
                 Key: SOLR-10159
                 URL: https://issues.apache.org/jira/browse/SOLR-10159
             Project: Solr
          Issue Type: Bug
      Security Level: Public (Default Security Level. Issues are Public)
            Reporter: Ishan Chattopadhyaya


h2. Background/History
If a recently updated (in-place) value is used for DBQ, the DBQ doesn't work at Lucene level, unless there's an explicit commit between the update and the DBQ, due to LUCENE-7344. To work around this, Yonik suggested that we use ulog.openRealtimeSearcher() just before the DBQ is performed. This worked fine.

Example:
{code}
ADD: [id=0, dv=200, title="mytitle", \_version\_=100]
UPD: [id=0, dv=300, \_version\_=200]
DBQ: q="dv:300"}}, \_version\_=300
{code}

h2. Problem discovered now
Suppose, in the above example, the last two commands are reordered at the replica. What would happen is: \(i\) the full document (\_version\_ 100) is received and indexed, (ii) the DBQ is received (out of ordered) and applied, and no document is deleted \[so far so good\] and this DBQ is buffered in ulog.deleteByQueries map, (iii) the in-place update arrives (_version 200), it is applied to the document that was added in step i. After that, the buffered DBQ is applied (at DUH2.addAndDelete()). This buffered DBQ, based on a value updated immediately before (step ii), fails to delete the document.

h2. What happens exactly?
The initial DBQ query is {{"dv:300"}}, but when it is applied, it is expanded to {{"\+dv:\[300 TO 300\] -ConstantScore(frange(long(\_version\_)):\[300 TO *\])"}}. In spite of doing a ulog.openRealtimeSearcher() just before the DBQ, it doesn't work. 

A different version of the query, i.e. {{"\+dv:\[300 TO 300\] \+\_version\_:\[200 TO 200\]"}} also doesn't work. As I found out, this happened due to the presence of two clauses! {{"\+dv:\[300 TO 300\]"}} works, and so does {{"\+\_version\_:\[200 TO 200\]"}}, but both clauses don't work together. Also, surprisingly, even {{"\+dv:\[300 TO 300\] \+dv:\[300 TO 300\]"}} doesn't work (same clause repeated).

h2. Investigation at Lucene level
Upon some tedious investigation into the internals of Lucene, I discovered that if I change the internal search (at BufferedUpdates) to use Sort.RELEVANCE instead of Sort.INDEXSORTING (which, I think is the default when using weight/scorer), the DBQ is applied correctly.



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