SQL search_type does not support slicing. slice_max will be…

Error message

SQL search_type does not support slicing. slice_max will be ignored.

What it means

Elasticsearch SQL search_type does not support the slice-based parallelism used by scroll/PIT. If search_type=sql and slice_max > 1, the connector logs this warning and resets sliceMax to 1, so the reader will not be parallelized by slicing.

Solutions

Remove slice_max or set it to 1 when using search_type=sql
Switch search_type to scroll/pit if parallel slicing is needed and the query allows
Accept single-threaded SQL reading

Example fix

// before
search_type = "sql"
slice_max = 5
// after
search_type = "sql"
# slice_max removed
// or for parallelism:
search_type = "pit"
slice_max = 5

Defensive patterns

Strategy: validation

Validate before calling

// fail fast on incompatible combination
if ("sql".equals(config.getString("search_type")) && config.getInt("slice_max", 1) > 1) {
    throw new IllegalArgumentException("slice_max is not supported with search_type=sql");
}

Prevention

Only set slice_max for scroll/pit search types
Don't reuse slice_max across search_type variants in templates
Verify expected reader parallelism after switching search_type

When it happens

Trigger: Setting search_type = "sql" together with slice_max > 1 in the Elasticsearch source config.

Common situations: Users expecting SQL queries to be parallel like scroll/PIT reads; leftover slice_max from a config template.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/47e23d2f6c393657. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-connectors-v2/connector-elasticsearch/src/main/java/org/apache/seatunnel/connectors/seatunnel/elasticsearch/source/ElasticsearchSource.java:176

                                sourceType,
                                null));
            }
            catalogTable =
                    CatalogTable.of(
                            TableIdentifier.of("elasticsearch", null, index),
                            builder.build(),
                            Collections.emptyMap(),
                            Collections.emptyList(),
                            "");
        }
        SearchTypeEnum searchType = readonlyConfig.get(SEARCH_TYPE);
        SearchApiTypeEnum searchApiType = readonlyConfig.get(SEARCH_API_TYPE);
        String sqlQuery = readonlyConfig.get(ElasticsearchSourceOptions.SQL_QUERY);
        String scrollTime = readonlyConfig.get(ElasticsearchSourceOptions.SCROLL_TIME);
        int scrollSize = readonlyConfig.get(ElasticsearchSourceOptions.SCROLL_SIZE);
        int sliceMax = readonlyConfig.get(ElasticsearchSourceOptions.SLICE_MAX);
        if (SearchTypeEnum.SQL.equals(searchType) && sliceMax > 1) {
            log.warn("SQL search_type does not support slicing. slice_max will be ignored.");
            sliceMax = 1;
        }

        long pitKeepAlive = readonlyConfig.get(ElasticsearchSourceOptions.PIT_KEEP_ALIVE);
        int pitBatchSize = readonlyConfig.get(ElasticsearchSourceOptions.PIT_BATCH_SIZE);

        // Parse runtime fields configuration
        Map<String, Object> runtimeFields = null;
        if (readonlyConfig.getOptional(ElasticsearchSourceOptions.RUNTIME_FIELDS).isPresent()) {
            runtimeFields =
                    parseRuntimeFields(
                            readonlyConfig.get(ElasticsearchSourceOptions.RUNTIME_FIELDS));
        }

        ElasticsearchConfig elasticsearchConfig = new ElasticsearchConfig();
        elasticsearchConfig.setSource(source);
        elasticsearchConfig.setCatalogTable(catalogTable);
        elasticsearchConfig.setQuery(query);

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