[GitHub] [spark] huaxingao commented on a diff in pull request #39954: [SPARK-42289][SQL] DS V2 pushdown could let JDBC dialect decide to push down offset and limit

["huaxingao (via GitHub)" <gi...@apache.org>]

huaxingao commented on code in PR #39954:
URL: https://github.com/apache/spark/pull/39954#discussion_r1113730251


##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/JdbcDialects.scala:
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@@ -557,6 +557,20 @@ abstract class JdbcDialect extends Serializable with Logging {
   def getJdbcSQLQueryBuilder(options: JDBCOptions): JdbcSQLQueryBuilder =
     new JdbcSQLQueryBuilder(this, options)
 
+  /**
+   * Returns ture if dialect supports LIMIT clause.
+   *
+   * Note: Some build-in dialect supports LIMIT clause with some trick, please see:
+   * {@link OracleDialect.OracleSQLQueryBuilder} and
+   * {@link MsSqlServerDialect.MsSqlServerSQLQueryBuilder}.
+   */
+  def supportsLimit: Boolean = true
+
+  /**
+   * Returns ture if dialect supports OFFSET clause.
+   */
+  def supportsOffset: Boolean = true

Review Comment:
   Do all the dialects support offset? If not, do we need to set this to false in the dialect?
   
   BTW you still have this `TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset` in `OracleDialect` and `MsSqlServerDialect`



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