[SOLR-15353] Querying multiple collection performance issue

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Duplicate
• Affects Version/s: 8.8.1
• Component/s: search

Environment

SolrCloud Setup: 3 zookeeper servers and 2 solr cloud nodes

each Solr node hosted in AWS m5.xlarge EC2 with 8G RAM dedicated to Solr JVM heap 
in this environment each collection is one shard and 2 replicas

for benchmarking i've used JMeter, setting the thread group=50, and loop count=500

 

• Assignee: Unassigned
• Reporter: Mazen Raafat
• Created: 19/Apr/21 01:27
• Updated: 23/Jun/21 13:49
• Resolved: 11/Jun/21 17:39

Description

performance degradation when querying multiple collections using aliases that points to multiple collection or calling the search handler directly with  collection query param as follow

http://localhost:8983/solr/collection1/select?collection=collection1,collection2,collection3

 

in the first test i have queried a collection with about 40k docs, the throughput was ~3k req/sec

in the second test  i have queried another collection with about 4k docs, the throughput was ~3.5k req/sec

in the third test i have queried an alias that points to both collections and viola! the throughput dropped to be ~200 req/sec!

i have tried not to use alias and use solrurl/solr/collection1/select?collections=collection2 and got the same result

 

notes:

1. both collections have the same schema
2. query and filter query are the same in all tests