[SOLR-7128] Two phase distributed search is fetching extra fields in GET_TOP_IDS phase

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 4.10.2, 4.10.3
• Fix Version/s: 4.10.4, 5.1, 6.0
• Component/s: search
• Assignee: Shalin Shekhar Mangar
• Reporter: Shalin Shekhar Mangar
• Created: 19/Feb/15 19:21
• Updated: 02/Oct/19 17:23
• Resolved: 27/Feb/15 19:45

Description

pqueixalos reported this to me privately so I am creating this issue on his behalf.

We found an issue in versions 4.10.+ (4.10.2 and 4.10.3 for sure).

When processing a two phase distributed query with an explicit fl parameter, the two phases are well processed, but the GET_TOP_IDS retrieves the matching documents fields, even if a GET_FIELDS shard request is getting executed just after.

/solr/someCollectionCore?collection=someOtherCollection&q=:&debug=true&fl=id,title
=> id is retrieved during GET_TOP_IDS phase that's ok:: it's our uniqueKeyField
=> title is also retrieved during GET_TOP_IDS phase, that's not ok.

I'm able to reproduce this. This is pretty bad performance bug that was introduced in SOLR-5768 or it's subsequent related issues. I plan to fix this bug and add substantial tests to assert such things.

Issue Links

• relates to: SOLR-7147 Introduce new TrackingShardHandlerFactory for monitoring what requests are sent to shards during tests