[jira] [Created] (SOLR-16587) Solr 9.1.0 last page retrieval error

["Andrei Minin (Jira)" <ji...@apache.org>]

Andrei Minin created SOLR-16587:
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             Summary: Solr 9.1.0 last page retrieval error
                 Key: SOLR-16587
                 URL: https://issues.apache.org/jira/browse/SOLR-16587
             Project: Solr
          Issue Type: Bug
      Security Level: Public (Default Security Level. Issues are Public)
          Components: search
         Environment: Solr 9.1.0

Search with wildcard query **:* (all match) and reading pages without cursor until last page*
            Reporter: Andrei Minin


When searching with offset, last page fails by internal assert.

For example there are 210 documents in index matching criteria and I am reading documents using page size =100; 3rd page with range 200 to 300 fails. Same unit test runs OK on Solr 8.11 and 9.0.0

Debugging details:

class  org.apache.solr.search.SolrIndexSearcher method 

{color:#cc7832}private void {color}{color:#ffc66d}getDocListC{color}(QueryResult qr{color:#cc7832}, {color}QueryCommand cmd)

receives command

cmd = \{QueryCommand@12109} 
 query = \{MatchAllDocsQuery@12121} "*:*"
 queryID = null
 isQueryCancellable = false
 filterList = null
 filter = null
 sort = null
 offset = 200
 len = 200
 supersetMaxDoc = 220
 flags = 0
 timeAllowed = -1
 minExactCount = 2147483647
 cursorMark = null

On line 1650:

out.docList = constantScoreDocList(cmd.getOffset(), cmd.getLen(), out.docSet);

docList created with 10 documents (correct):

out.docList = \{DocSlice@12126} 
 offset = 0
 len = 10
 docs = \{int[10]@12129} [200, 201, 202, 203, 204, 205, 206, 207, 208, 209]
 scores = null
 matches = 210
 matchesRelation = \{TotalHits$Relation@12078} "EQUAL_TO"
 maxScore = 0.0
 ramBytesUsed = 112

But on line 1687 it is converted to null because cmd offset (200) and lenght (200) applied to this 10 documents list (thru reassigning superset):
 / Kludge...
      // we can't use DocSlice.subset, even though it should be an identity op
      // because it gets confused by situations where there are lots of matches, but
      // less docs in the slice then were requested, (due to the cursor)
      // so we have to short circuit the call.
      // None of which is really a problem since we can't use caching with
      // cursors anyway, but it still looks weird to have to special case this
      // behavior based on this condition - hence the long explanation.
       superset = out.docList;
      out.docList = superset.subset(cmd.getOffset(), cmd.getLen());

As result, null docList returned from method (instead of 10 documents list)

and failed later in class  org.apache.solr.response.BasicResultContext on assert on line 39:

{color:#cc7832}assert {color}docList != {color:#cc7832}null;{color}

In my opition, there is an error on line 1688 in class SolrIndexSearcher:

out.docList = superset.subset(cmd.getOffset(), cmd.getLen());

this line shouldn't be called or called with different parameters.

Honestly I don't understand logic of this line, what is the reason for recursive subset call?

2 lines can be presented as:

out.docList = out.docList.subset(cmd.getOffset(), cmd.getLen());



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