Error querying Atlas index

[Jason_Tran]

Hi @Wayne_Smallman,

@Wayne_Smallman

query has expanded into too many sub-queries internally: maxClauseCount is set to 1024

Thanks for providing the search details and the error message. I assume you’re getting this error against an M0, M2 or M5 tier cluster - please correct me if I am wrong here. This assumption is based off the Atlas Search M0 (Free Cluster), M2, and M5 Limitations documentation which states:

• Lucene’s default clause limit of 1024 applies to any BooleanQuery created for searches.

More details on the clause error and its possible cause(s) can be found in the Lucene documentation here.

There a few options you may wish to consider or test out:

1. Tweak the Atlas Search query to:
   • Reduce the number of search terms (e.g. From “Generic Error” to “Generic”)
   • Altering the minGram value from 4 to 5 (or higher, as an example)
   • Changing from nGram to edgeGram
   • Combination / mix-n-match of all of the above points
2. Creating a new M10 tier or higher cluster and importing the same data as your current environment where the error is being generated + re-creating the same atlas search index.
   • Note: I write creating a new cluster as you cannot downgrade an M10+ tier cluster back down to M0, M2 or M5. If your testing verifies that the M10+ tier resolves the error messages then perhaps you can then consider upgrading the original cluster.

Just to also dive a bit deeper into the issue, could you also advise what search terms you’re using that are generating this error?

Regards,
Jason