Add comments to SqlSession

Original commit: elastic/x-pack-elasticsearch@82291d41c8

qa/sql/src/main/java/org/elasticsearch/xpack/qa/sql/jdbc/CsvSpecTestCase.java

@@ -34,7 +34,7 @@ import static org.hamcrest.Matchers.arrayWithSize;
  * Tests comparing sql queries executed against our jdbc client
  * with hard coded result sets.
  */
-public class CsvSpecTestCase extends SpecBaseIntegrationTestCase {
+public abstract class CsvSpecTestCase extends SpecBaseIntegrationTestCase {
     private final CsvTestCase testCase;
 
     @ParametersFactory(argumentFormatting = PARAM_FORMATTING)

qa/sql/src/main/java/org/elasticsearch/xpack/qa/sql/jdbc/SqlSpecTestCase.java

@@ -19,7 +19,7 @@ import java.util.List;
  * Tests comparing sql queries executed against our jdbc client
  * with those executed against H2's jdbc client.
  */
-public class SqlSpecTestCase extends SpecBaseIntegrationTestCase {
+public abstract class SqlSpecTestCase extends SpecBaseIntegrationTestCase {
     private String query;
 
     @ClassRule

sql/server/src/main/java/org/elasticsearch/xpack/sql/analysis/analyzer/Analyzer.java

@@ -266,7 +266,6 @@ public class Analyzer extends RuleExecutor<LogicalPlan> {
             }
             if (found == null) {
                 return plan;
-                //throw new UnknownIndexException(table.index(), plan);
             }
 
             LogicalPlan catalogTable = new EsRelation(plan.location(), found);

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/function/UnresolvedFunction.java

@@ -25,6 +25,15 @@ public class UnresolvedFunction extends Function implements Unresolvable {
         this(location, name, distinct, children, null);
     }
 
+    /**
+     * Constructor used for specifying a more descriptive message (typically 'did you mean') instead of the default one.
+     * 
+     * @param location
+     * @param name
+     * @param distinct
+     * @param children
+     * @param unresolvedMessage
+     */
     public UnresolvedFunction(Location location, String name, boolean distinct, List<Expression> children, String unresolvedMessage) {
         super(location, children);
         this.name = name;