elastic/elasticsearch · error · IllegalStateException

Cannot merge SEARCH_TIME and INDEX_TIME analysis mode.

Error message

Cannot merge SEARCH_TIME and INDEX_TIME analysis mode.

What it means

Thrown by AnalysisMode.INDEX_TIME.merge(other) when other == SEARCH_TIME. AnalysisMode models whether a token filter/analyzer component is allowed at index time, search time, both (ALL), or neither (NONE). Merging INDEX_TIME with SEARCH_TIME is impossible because a single component cannot be both exclusively-index and exclusively-search; the merge throws IllegalStateException to flag an inconsistent analyzer configuration.

Source

Thrown at libs/plugin-analysis-api/src/main/java/org/elasticsearch/plugin/analysis/AnalysisMode.java:26

 */

package org.elasticsearch.plugin.analysis;

/**
 * Enum representing the mode in which token filters and analyzers are allowed to operate.
 * While most token filters are allowed both in index and search time analyzers, some are
 * restricted to be used only at index time, others at search time.
 */
public enum AnalysisMode {

    /**
     * AnalysisMode representing analysis components that can be used only at index time.
     */
    INDEX_TIME("index time") {
        @Override
        public AnalysisMode merge(AnalysisMode other) {
            if (other == AnalysisMode.SEARCH_TIME) {
                throw new IllegalStateException("Cannot merge SEARCH_TIME and INDEX_TIME analysis mode.");
            }
            return AnalysisMode.INDEX_TIME;
        }
    },
    /**
     * AnalysisMode representing analysis components that can be used only at search time.
     */
    SEARCH_TIME("search time") {
        @Override
        public AnalysisMode merge(AnalysisMode other) {
            if (other == AnalysisMode.INDEX_TIME) {
                throw new IllegalStateException("Cannot merge SEARCH_TIME and INDEX_TIME analysis mode.");
            }
            return AnalysisMode.SEARCH_TIME;
        }
    },
    /**
     * AnalysisMode representing analysis components that can be used both at index and search time.

View on GitHub (pinned to db6a809a66)

Solutions

1. Split the analyzer into separate index-time and search-time configurations so no single chain mixes INDEX_TIME and SEARCH_TIME components.
2. Re-check each component's declared AnalysisMode and switch the offending one to ALL if it is genuinely usable at both phases.
3. If you author the component, set AnalysisMode to match its real capabilities rather than over-restricting it.
4. Validate the analyzer definition at config-load time and report which two filters conflict by name.

Example fix

// before: one analyzer mixes modes
"analysis": {
  "analyzer": { "my": { "filter": ["index_only_syn", "search_only_norm"] } }
}

// after: separate analyzers per phase
"analysis": {
  "analyzer": {
    "my_index": { "filter": ["index_only_syn"] },
    "my_search": { "filter": ["search_only_norm"] }
  }
}

// Walk the analyzer's filter chain and reject conflicting AnalysisMode merges up front.
AnalysisMode acc = AnalysisMode.ALL;
for (AnalysisComponent c : filters) {
    AnalysisMode m = c.analysisMode();
    if ((acc == AnalysisMode.INDEX_TIME && m == AnalysisMode.SEARCH_TIME)
     || (acc == AnalysisMode.SEARCH_TIME && m == AnalysisMode.INDEX_TIME)) {
        throw new IllegalArgumentException("Analyzer mixes INDEX_TIME and SEARCH_TIME filters: " + c.name());
    }
    acc = acc.merge(m);
}

try {
    AnalysisMode merged = a.merge(b);
} catch (IllegalStateException e) {
    throw new IllegalArgumentException("Cannot build analyzer: index-only and search-only filters are incompatible", e);
}

When it happens

Trigger: A multi-component analyzer/filter chain where one component declares AnalysisMode.INDEX_TIME and another declares AnalysisMode.SEARCH_TIME, and the framework merges their modes to decide where the analyzer can run. E.g. a custom analyzer combining an index-only synonym filter with a search-only normalization filter.

Common situations: Adding a search-only filter (e.g. some stemmer variants) to an analyzer also used at index time, or vice-versa; plugin authors setting the wrong AnalysisMode on a token filter; upgrading a filter whose mode changed between versions.

Related errors

• synonym requires either `synonyms`, `synonyms_set` or `synon
• update_offsets is not supported anymore. Please fix your ana
• length parameter must be provided
• Token filter [{name()}] cannot be used to parse synonyms
• Token filter [{name()}] cannot be used to parse synonyms

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/53f9ba23282fc3f9. Report an issue: GitHub.