[8.19] Use standard tokenizer in ES|QL categorize (#129642)

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/job/config/CategorizationAnalyzerConfig.java

@@ -210,6 +210,22 @@ public static CategorizationAnalyzerConfig buildStandardCategorizationAnalyzer(L
             .build();
     }
 
+    /**
+     * Create a <code>categorization_analyzer</code> that will be used by the ES|QL categorize function.
+     * The only difference from the DSL analyzer is the tokenizer (standard instead of ml_standard).
+     * This means the results are slightly different from the categorize text aggregation and the ML job,
+     * however you can use these tokens for looking up messages in indices generated with the standard
+     * tokenizer. The latter is considered more important.
+     */
+    public static CategorizationAnalyzerConfig buildStandardEsqlCategorizationAnalyzer() {
+
+        return new CategorizationAnalyzerConfig.Builder().addCharFilter("first_line_with_letters")
+            .setTokenizer("standard")
+            .addDateWordsTokenFilter()
+            .addLimitFilter()
+            .build();
+    }
+
     private final String analyzer;
     private final List<NameOrDefinition> charFilters;
     private final NameOrDefinition tokenizer;

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/aggregation/blockhash/CategorizeBlockHash.java

@@ -39,7 +39,6 @@
 
 import java.io.IOException;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
@@ -48,9 +47,8 @@
  */
 public class CategorizeBlockHash extends BlockHash {
 
-    private static final CategorizationAnalyzerConfig ANALYZER_CONFIG = CategorizationAnalyzerConfig.buildStandardCategorizationAnalyzer(
-        List.of()
-    );
+    private static final CategorizationAnalyzerConfig ANALYZER_CONFIG = CategorizationAnalyzerConfig
+        .buildStandardEsqlCategorizationAnalyzer();
     private static final int NULL_ORD = 0;
 
     private final int channel;