🚀 UPDATE – July 9, 2024

Heads up, Solr wranglers! We’ve moved the maxBooleanClauses setting into your solr.xml (in your Solr home directory alongside your cores/collections).

<solr>
  <int name="maxBooleanClauses">90589</int>  <!-- 🛠️ Bump your limit here -->
  <shardHandlerFactory name="shardHandlerFactory"
                       class="HttpShardHandlerFactory">
    <int name="socketTimeout">${socketTimeout:600000}</int>
    <int name="connTimeout">${connTimeout:60000}</int>
  </shardHandlerFactory>
</solr>

😱 Symptom

org.apache.solr.common.SolrException: Too many boolean clauses (1025).

• Default limit: 1024 clauses.
• Triggers: large synonym files, wildcard expansions, or overly broad query filters.

🔍 Root Causes

• Synonym explosion: Each synonym generates extra clauses.
• Wildcard & prefix queries: * or leading wildcards (*term) expand to many terms.
• Massive stopword/protword lists: Improperly positioned filters multiply clauses.

🛠️ Solutions

1. Increase maxBooleanClauses
   Adjust in solr.xml (as shown above).

2. Trim your word lists

3. synonyms.txt
4. stopwords.txt

5. protwords.txt
   Remove rarely used terms to reduce clause count.

6. Optimize filter chain

7. Apply synonyms at query time using SynonymGraphFilterFactory, not at index time.

8. Place stop and prot word filters before wildcard or graph filters.

9. Avoid expansive wildcards

10. Prefer prefix queries (term*) over leading wildcards.
11. Use edge n-gram tokenizers for partial matching.

Keep calm and Solr on! 😎🖋️