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Posted to reviews@spark.apache.org by "beliefer (via GitHub)" <gi...@apache.org> on 2023/03/10 05:55:31 UTC
[GitHub] [spark] beliefer opened a new pull request, #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
beliefer opened a new pull request, #40359:
URL: https://github.com/apache/spark/pull/40359
### What changes were proposed in this pull request?
Currently, the DS V2 pushdown framework pushed offset as `OFFSET n` in default and pushed it with limit as `LIMIT m OFFSET n`. But some built-in dialect doesn't support these syntax. So, when Spark pushdown offset into these databases, them throwing errors.
### Why are the changes needed?
Fix the bug that pushdown offset or paging is invalid for some built-in dialect.
### Does this PR introduce _any_ user-facing change?
'Yes'.
The bug will be fixed.
### How was this patch tested?
New test cases.
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132004161
##########
connector/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/v2/V2JDBCTest.scala:
##########
@@ -410,6 +410,15 @@ private[v2] trait V2JDBCTest extends SharedSparkSession with DockerIntegrationFu
assert(sorts.isEmpty)
}
+ private def checkOffsetPushed(df: DataFrame, offset: Option[Int]): Unit = {
Review Comment:
can we rename `limitPushed` to `checkLimitPushed` and follow the implementation here?
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132005986
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
Review Comment:
nvm, I see the implementation.
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132157169
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,22 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
+ val offsetClause = dialect.getOffsetClause(offset)
+ options.prepareQuery +
+ s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
+ s" $whereClause $groupByClause $orderByClause LIMIT 18446744073709551610 $offsetClause"
Review Comment:
MySQL doesn't support offset without limit.
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1133011143
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,26 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
Review Comment:
if limit = 0, Optimizer will convert it to empty relation. But it's OK to use `limit < 0`.
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1133011143
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,26 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
Review Comment:
if limit = 0, Optimizer will convert it to empty relation. But it's OK to use `limit < 0` too.
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[GitHub] [spark] beliefer commented on pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on PR #40359:
URL: https://github.com/apache/spark/pull/40359#issuecomment-1465460479
> thanks, merged to master! can you open a backport PR for 3.4?
Thank you! I will create it.
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[GitHub] [spark] beliefer commented on pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on PR #40359:
URL: https://github.com/apache/spark/pull/40359#issuecomment-1463340665
ping @cloud-fan cc @sadikovi
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132005699
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
Review Comment:
every table in oracle has the `rn` column?
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[GitHub] [spark] cloud-fan commented on pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on PR #40359:
URL: https://github.com/apache/spark/pull/40359#issuecomment-1465448190
thanks, merged to master! can you open a backport PR for 3.4?
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132156623
##########
connector/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/v2/V2JDBCTest.scala:
##########
@@ -410,6 +410,15 @@ private[v2] trait V2JDBCTest extends SharedSparkSession with DockerIntegrationFu
assert(sorts.isEmpty)
}
+ private def checkOffsetPushed(df: DataFrame, offset: Option[Int]): Unit = {
Review Comment:
Let's do it in another PR.
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132460230
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
+ if (offset > 0) s"WHERE rn > $offset" else ""
+ }
+
class OracleSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
extends JdbcSQLQueryBuilder(dialect, options) {
- // TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset
override def build(): String = {
val selectStmt = s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
s" $whereClause $groupByClause $orderByClause"
- if (limit > 0) {
- val limitClause = dialect.getLimitClause(limit)
- options.prepareQuery + s"SELECT tab.* FROM ($selectStmt) tab $limitClause"
+ val finalSelectStmt = if (limit > 0) {
+ if (offset > 0) {
+ s"SELECT $columnList FROM (SELECT tab.*, rownum rn FROM ($selectStmt) tab)" +
Review Comment:
or we can use the new syntax in oracle 12+, which should be the widely used versions today.
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1133009134
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
+ if (offset > 0) s"WHERE rn > $offset" else ""
+ }
+
class OracleSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
extends JdbcSQLQueryBuilder(dialect, options) {
- // TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset
override def build(): String = {
val selectStmt = s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
s" $whereClause $groupByClause $orderByClause"
- if (limit > 0) {
- val limitClause = dialect.getLimitClause(limit)
- options.prepareQuery + s"SELECT tab.* FROM ($selectStmt) tab $limitClause"
+ val finalSelectStmt = if (limit > 0) {
+ if (offset > 0) {
+ s"SELECT $columnList FROM (SELECT tab.*, rownum rn FROM ($selectStmt) tab)" +
Review Comment:
> or we can use the new syntax in oracle 12+, which should be the widely used versions today.
Could we upgrade the version of oracle in another PR if it is widely used.
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132457170
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
+ if (offset > 0) s"WHERE rn > $offset" else ""
+ }
+
class OracleSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
extends JdbcSQLQueryBuilder(dialect, options) {
- // TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset
override def build(): String = {
val selectStmt = s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
s" $whereClause $groupByClause $orderByClause"
- if (limit > 0) {
- val limitClause = dialect.getLimitClause(limit)
- options.prepareQuery + s"SELECT tab.* FROM ($selectStmt) tab $limitClause"
+ val finalSelectStmt = if (limit > 0) {
+ if (offset > 0) {
+ s"SELECT $columnList FROM (SELECT tab.*, rownum rn FROM ($selectStmt) tab)" +
Review Comment:
https://stackoverflow.com/questions/31186166/oracle-sql-filtering-by-rownum-not-returning-results-when-it-should
Let's mention the reason as well: the `rownum` is calculated when the value is returned.
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132448651
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,26 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
Review Comment:
is it possible to have limit = 0? seems safer to use `limit < 0` to indicate no limit.
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,26 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
Review Comment:
is it possible to have limit = 0? seems safer to use `limit < 0` to indicate no limit, as the default value is -1
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[GitHub] [spark] cloud-fan closed pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan closed pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
URL: https://github.com/apache/spark/pull/40359
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132007081
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
##########
@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
+ if (offset > 0) s"WHERE rn > $offset" else ""
+ }
+
class OracleSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
extends JdbcSQLQueryBuilder(dialect, options) {
- // TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset
override def build(): String = {
val selectStmt = s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
s" $whereClause $groupByClause $orderByClause"
- if (limit > 0) {
- val limitClause = dialect.getLimitClause(limit)
- options.prepareQuery + s"SELECT tab.* FROM ($selectStmt) tab $limitClause"
+ val finalSelectStmt = if (limit > 0) {
+ if (offset > 0) {
+ s"SELECT $columnList FROM (SELECT tab.*, rownum rn FROM ($selectStmt) tab)" +
Review Comment:
how about
```
SELECT * FROM ($selectStmt) tab WHERE rownum > ...
```
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[GitHub] [spark] cloud-fan commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132005206
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MySQLDialect.scala:
##########
@@ -291,4 +291,22 @@ private case object MySQLDialect extends JdbcDialect with SQLConfHelper {
throw QueryExecutionErrors.unsupportedDropNamespaceRestrictError()
}
}
+
+ class MySQLSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
+ extends JdbcSQLQueryBuilder(dialect, options) {
+
+ override def build(): String = {
+ if (limit < 1 && offset > 0) {
+ val offsetClause = dialect.getOffsetClause(offset)
+ options.prepareQuery +
+ s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
+ s" $whereClause $groupByClause $orderByClause LIMIT 18446744073709551610 $offsetClause"
Review Comment:
what does this `LIMIT 18446744073709551610` mean?
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[GitHub] [spark] beliefer commented on a diff in pull request #40359: [SPARK-42740][SQL] Fix the bug that pushdown offset or paging is invalid for some built-in dialect
Posted by "beliefer (via GitHub)" <gi...@apache.org>.
beliefer commented on code in PR #40359:
URL: https://github.com/apache/spark/pull/40359#discussion_r1132181650
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/OracleDialect.scala:
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@@ -181,19 +181,35 @@ private case object OracleDialect extends JdbcDialect {
if (limit > 0) s"WHERE rownum <= $limit" else ""
}
+ override def getOffsetClause(offset: Integer): String = {
+ // Oracle doesn't support OFFSET clause.
+ // We can use rownum > n to skip some rows in the result set.
+ // Note: rn is an alias of rownum.
+ if (offset > 0) s"WHERE rn > $offset" else ""
+ }
+
class OracleSQLQueryBuilder(dialect: JdbcDialect, options: JDBCOptions)
extends JdbcSQLQueryBuilder(dialect, options) {
- // TODO[SPARK-42289]: DS V2 pushdown could let JDBC dialect decide to push down offset
override def build(): String = {
val selectStmt = s"SELECT $columnList FROM ${options.tableOrQuery} $tableSampleClause" +
s" $whereClause $groupByClause $orderByClause"
- if (limit > 0) {
- val limitClause = dialect.getLimitClause(limit)
- options.prepareQuery + s"SELECT tab.* FROM ($selectStmt) tab $limitClause"
+ val finalSelectStmt = if (limit > 0) {
+ if (offset > 0) {
+ s"SELECT $columnList FROM (SELECT tab.*, rownum rn FROM ($selectStmt) tab)" +
Review Comment:
Maybe it is a bug of Oracle.
If we using rownum directly, the result will incorrect.
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