nsivabalan commented on code in PR #5244:
URL: https://github.com/apache/hudi/pull/5244#discussion_r845614938
##########
hudi-spark-datasource/hudi-spark-common/src/main/scala/org/apache/hudi/HoodieFileIndex.scala:
##########
@@ -196,12 +191,20 @@ case class HoodieFileIndex(spark: SparkSession,
* @return list of pruned (data-skipped) candidate base-files' names
*/
private def lookupCandidateFilesInMetadataTable(queryFilters:
Seq[Expression]): Try[Option[Set[String]]] = Try {
- if (!isDataSkippingEnabled || queryFilters.isEmpty ||
!HoodieTableMetadataUtil.getCompletedMetadataPartitions(metaClient.getTableConfig)
- .contains(HoodieTableMetadataUtil.PARTITION_NAME_COLUMN_STATS)) {
+ // NOTE: Data Skipping is only effective when it references columns that
are indexed w/in
+ // the Column Stats Index (CSI). Following cases could not be
effectively handled by Data Skipping:
+ // - Expressions on top-level column's fields (ie, for ex filters
like "struct.field > 0", since
+ // CSI only contains stats for top-level columns, in this case
for "struct")
+ // - Any expression not directly referencing top-level column
(for ex, sub-queries, since there's
+ // nothing CSI in particular could be applied for)
+ lazy val queryReferencedColumns = collectReferencedColumns(spark,
queryFilters, schema)
+
+ if (!isMetadataTableEnabled || !isColumnStatsIndexEnabled ||
!isColumnStatsIndexAvailable || !isDataSkippingEnabled) {
Review Comment:
we can probably go w/ 3 guards here
!isMetadataTableEnabled || !isColumnStatsIndexAvailable ||
!isDataSkippingEnabled
to utilize base metadata itself, one has to enable explicitly on the read
path. So, I prefer to guard that. and then check if data skipping is enabled.
And then only if col stats partition is available to be used.
##########
hudi-spark-datasource/hudi-spark-common/src/main/scala/org/apache/hudi/HoodieFileIndex.scala:
##########
@@ -196,12 +191,20 @@ case class HoodieFileIndex(spark: SparkSession,
* @return list of pruned (data-skipped) candidate base-files' names
*/
private def lookupCandidateFilesInMetadataTable(queryFilters:
Seq[Expression]): Try[Option[Set[String]]] = Try {
- if (!isDataSkippingEnabled || queryFilters.isEmpty ||
!HoodieTableMetadataUtil.getCompletedMetadataPartitions(metaClient.getTableConfig)
- .contains(HoodieTableMetadataUtil.PARTITION_NAME_COLUMN_STATS)) {
+ // NOTE: Data Skipping is only effective when it references columns that
are indexed w/in
+ // the Column Stats Index (CSI). Following cases could not be
effectively handled by Data Skipping:
+ // - Expressions on top-level column's fields (ie, for ex filters
like "struct.field > 0", since
+ // CSI only contains stats for top-level columns, in this case
for "struct")
+ // - Any expression not directly referencing top-level column
(for ex, sub-queries, since there's
+ // nothing CSI in particular could be applied for)
+ lazy val queryReferencedColumns = collectReferencedColumns(spark,
queryFilters, schema)
+
+ if (!isMetadataTableEnabled || !isColumnStatsIndexEnabled ||
!isColumnStatsIndexAvailable || !isDataSkippingEnabled) {
Review Comment:
we can probably go w/ 3 guards here
!isMetadataTableEnabled || !isColumnStatsIndexAvailable ||
!isDataSkippingEnabled
to utilize base metadata itself, one has to enable explicitly on the read
path. So, I prefer to guard that. and then check if data skipping is enabled.
And then only if col stats partition is available to be used.
##########
hudi-common/src/main/java/org/apache/hudi/common/config/HoodieMetadataConfig.java:
##########
@@ -48,7 +48,8 @@
.sinceVersion("0.7.0")
.withDocumentation("Enable the internal metadata table which serves
table metadata like level file listings");
- public static final boolean DEFAULT_METADATA_ENABLE_FOR_READERS = false;
+ // TODO rectify
+ public static final boolean DEFAULT_METADATA_ENABLE_FOR_READERS = true;
Review Comment:
+1
##########
hudi-common/src/main/java/org/apache/hudi/common/config/HoodieMetadataConfig.java:
##########
@@ -48,7 +48,8 @@
.sinceVersion("0.7.0")
.withDocumentation("Enable the internal metadata table which serves
table metadata like level file listings");
- public static final boolean DEFAULT_METADATA_ENABLE_FOR_READERS = false;
+ // TODO rectify
+ public static final boolean DEFAULT_METADATA_ENABLE_FOR_READERS = true;
Review Comment:
+1
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
