[SOLR-7938] MergeStream to support N streams

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Affects Version/s: 6.0
• Fix Version/s: 6.0
• Component/s: SolrJ
• Labels: streaming
• Assignee: Dennis Gove
• Reporter: Dennis Gove
• Created: 17/Aug/15 14:20
• Updated: 09/May/16 18:57
• Resolved: 07/Nov/15 22:56

Description

Enhances MergeStream to support merging N streams. This was previously limited to merging just two streams but with this enhancement it can now accept any number of streams to merge.

Based on the comparator, if more than one stream could provide the next value then the selected value will follow the order of the streams as they appear in the expression or were added to the MergeStream object.

merge(
  search(collection1, q="id:(0 4)", fl="id,a_s,a_i,a_f", sort="a_f asc, a_s asc"),
  search(collection1, q="id:(1)", fl="id,a_s,a_i,a_f", sort="a_f asc, a_s asc"),
  search(collection1, q="id:(2)", fl="id,a_s,a_i,a_f", sort="a_f asc, a_s asc"),
  on="a_f asc"
)

Issue Links

• is related to: SOLR-8125 Umbrella ticket for Streaming and SQL issues