style: trim verbose comments per review

Per @penghuo: drop the verbose multi-line explanatory comments and tighten
the class/method javadoc on the new dashboard IT.

Signed-off-by: Kai Huang <ahkcs@amazon.com>

Author: ahkcs

api/src/main/java/org/opensearch/sql/api/UnifiedQueryContext.java

@@ -157,12 +157,6 @@ public static class Builder {
                     PPL_JOIN_SUBSEARCH_MAXOUT, SysLimit.UNLIMITED_SUBSEARCH.joinSubsearchLimit()),
                 Map.entry(CALCITE_ENGINE_ENABLED, true),
                 Map.entry(PPL_REX_MAX_MATCH_LIMIT, 10),
-                // PPL `patterns` command defaults — mirror the cluster-side defaults registered in
-                // OpenSearchSettings (DEFAULT_PATTERN_METHOD_SETTING etc.). Without these the
-                // analytics-engine path's AstBuilder.visitPatternsCommand reads null from
-                // `settings.getSettingValue(Key.PATTERN_METHOD)`, fails with
-                // `PatternMethod.valueOf("NULL")` IllegalArgumentException, and every query that
-                // omits an explicit `method=` / `mode=` argument is rejected.
                 Map.entry(PATTERN_METHOD, "SIMPLE_PATTERN"),
                 Map.entry(PATTERN_MODE, "LABEL"),
                 Map.entry(PATTERN_MAX_SAMPLE_COUNT, 10),

core/src/main/java/org/opensearch/sql/calcite/CalciteRelNodeVisitor.java

@@ -4303,12 +4303,8 @@ private void buildParseRelNode(Parse node, CalcitePlanContext context) {
     for (String groupCandidate : groupCandidates) {
       RexNode innerRex;
       if (ParseMethod.PATTERNS.equals(parseMethod)) {
-        // Emit `regexp_replace(field, pattern, replacement, "g")` directly so the replacement
-        // is global (every match replaced). DataFusion's `regexp_replace` defaults to FIRST
-        // match only without the "g" flag — using the 3-arg form via the REPLACE handler
-        // produces `<*>@pyrami.com` instead of `<*>@<*>.<*>` on the analytics-engine route.
-        // Calcite's REGEXP_REPLACE_PG_4 with "g" matches what `replaceAll` does, so V2 /
-        // Calcite-path semantics are preserved.
+        // Emit 4-arg REGEXP_REPLACE_PG_4 with "g" so DataFusion's regexp_replace
+        // (first-match-only by default) replaces every match.
         RexNode globalFlag =
             context.rexBuilder.makeLiteral(
                 "g", context.rexBuilder.getTypeFactory().createSqlType(SqlTypeName.VARCHAR), true);

integ-test/src/test/java/org/opensearch/sql/calcite/remote/CalcitePPLDashboardPatternsIT.java

@@ -14,29 +14,7 @@
 import org.junit.Test;
 import org.opensearch.sql.ppl.PPLIntegTestCase;
 
-/**
- * Pins the exact PPL query shape OpenSearch Dashboards uses to render BRAIN-pattern panels: {@code
- * patterns ... method=BRAIN mode=label} followed by {@code stats count(), take(message, 1) by
- * patterns_field | sort -pattern_count | fields patterns_field, pattern_count, sample_logs}.
- *
- * <p>The combination exercises three pieces that all have to be wired through the analytics-engine
- * route together:
- *
- * <ul>
- *   <li>{@code INTERNAL_PATTERN} as a window function (label mode emits one matched wildcard
- *       pattern per row, broadcast across the partition).
- *   <li>{@code take(field, n)} aggregate to capture a representative sample log per discovered
- *       pattern group.
- *   <li>{@code count()} aggregate + {@code sort} on the result.
- * </ul>
- *
- * <p>Schema-only assertions: BRAIN's clustering depends on a corpus large enough that the default
- * heuristics fire, so per-row pattern strings are sensitive to dataset version. The schema check
- * guarantees the query plans, executes, and returns the dashboard's three expected columns in the
- * right order.
- *
- * @opensearch.internal
- */
+/** Pins the BRAIN-label pattern panel query shape used by OpenSearch Dashboards. */
 public class CalcitePPLDashboardPatternsIT extends PPLIntegTestCase {
   @Override
   public void init() throws Exception {
@@ -45,11 +23,6 @@ public void init() throws Exception {
     loadIndex(Index.HDFS_LOGS);
   }
 
-  /**
-   * Mirrors the canonical Dashboards BRAIN-label pattern panel query. Unfiltered variant — pins the
-   * end-to-end plan compiles and returns the dashboard's three-column shape (matched wildcard
-   * pattern + occurrence count + sample log).
-   */
   @Test
   public void testDashboardBrainLabelStatsByPatternsField() throws IOException {
     JSONObject result =

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/serde/RexStandardizer.java

@@ -74,16 +74,10 @@ public RexNode visitCall(final RexCall call, ScriptParameterHelper helper) {
         // We can downgrade to still use `Sarg` literal instead of replacing it with parameter.
       }
     }
-    // PPL's `patterns` lowering emits 4-arg `REGEXP_REPLACE_PG_4(field, pattern, replacement,
-    // 'g')` so the analytics-engine/DataFusion path gets global replacement (DataFusion's
-    // `regexp_replace` defaults to first-match-only without an explicit flag). Calcite's
-    // 3-arg `REGEXP_REPLACE_3` is already replace-all in its enumerable runtime, but the PG_4
-    // form has no matching `SqlFunctions.regexpReplace(String, String, String, String)` impl
-    // — Calcite's runtime only ships the `(String, String, String, int[, ...])` shapes (the
-    // 4-arg variant treats the 4th arg as start-position, not a flags string). The script
-    // pushdown path codegen would fail with `No applicable constructor/method found`. Collapse
-    // the 4-arg call to the 3-arg form whenever the flags literal is exactly `"g"`, which
-    // preserves replace-all semantics on the V2 / Calcite-pushdown side.
+    // Calcite's enumerable runtime has no regexpReplace(String, String, String, String) impl,
+    // so 4-arg REGEXP_REPLACE_PG_4 fails Janino codegen on the script-pushdown path. Collapse
+    // to 3-arg REGEXP_REPLACE_3 when the flags literal is "g" — the 3-arg form is already
+    // replace-all, so semantics are preserved.
     if (call.op == SqlLibraryOperators.REGEXP_REPLACE_PG_4
         && call.operands.size() == 4
         && call.operands.get(3) instanceof RexLiteral flagsLit