[
https://issues.apache.org/jira/browse/HIVE-24663?focusedWorklogId=604357&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-604357
]
ASF GitHub Bot logged work on HIVE-24663:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 01/Jun/21 07:51
Start Date: 01/Jun/21 07:51
Worklog Time Spent: 10m
Work Description: deniskuzZ commented on a change in pull request #2266:
URL: https://github.com/apache/hive/pull/2266#discussion_r642865407
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
##########
@@ -5394,6 +5410,476 @@ public void countOpenTxns() throws MetaException {
}
}
+ private void cleanOldStatsFromPartColStatTable(Map<PartitionInfo,
ColumnStatistics> statsPartInfoMap,
+ Connection dbConn) throws
SQLException {
+ PreparedStatement preparedStatement = null;
+ int numRows = 0;
+ int maxNumRows = MetastoreConf.getIntVar(conf,
ConfVars.DIRECT_SQL_MAX_ELEMENTS_VALUES_CLAUSE);
+
+ // Index is present on DB_NAME,TABLE_NAME,COLUMN_NAME,PARTITION_NAME. use
that.
+ // TODO : Need to add catalog name to the index
+ String delete = "DELETE FROM \"PART_COL_STATS\" where \"DB_NAME\" = ? AND "
+ + "\"TABLE_NAME\" = ? AND \"COLUMN_NAME\" = ? AND
\"PARTITION_NAME\" = ? "
+ + "AND \"PART_ID\" = ?";
+
+ try {
+ preparedStatement = sqlGenerator.prepareStmtWithParameters(dbConn,
delete, null);
+ for (Map.Entry entry : statsPartInfoMap.entrySet()) {
+ ColumnStatistics colStats = (ColumnStatistics) entry.getValue();
+ PartitionInfo partitionInfo = (PartitionInfo) entry.getKey();
+ for (ColumnStatisticsObj statisticsObj : colStats.getStatsObj()) {
+ preparedStatement.setString(1, colStats.getStatsDesc().getDbName());
+ preparedStatement.setString(2,
colStats.getStatsDesc().getTableName());
+ preparedStatement.setString(3, statisticsObj.getColName());
+ preparedStatement.setString(4,
colStats.getStatsDesc().getPartName());
+ preparedStatement.setLong(5, partitionInfo.partitionId);
+ numRows++;
+ preparedStatement.addBatch();
+ if (numRows == maxNumRows) {
+ preparedStatement.executeBatch();
+ numRows = 0;
+ LOG.debug("Executed delete " + delete + " for numRows " + numRows);
+ }
+ }
+ }
+
+ if (numRows != 0) {
Review comment:
it's more for readablility
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Issue Time Tracking
-------------------
Worklog Id: (was: 604357)
Time Spent: 8h 20m (was: 8h 10m)
> Reduce overhead of partition column stats updation.
> ---------------------------------------------------
>
> Key: HIVE-24663
> URL: https://issues.apache.org/jira/browse/HIVE-24663
> Project: Hive
> Issue Type: Sub-task
> Reporter: Rajesh Balamohan
> Assignee: mahesh kumar behera
> Priority: Major
> Labels: performance, pull-request-available
> Time Spent: 8h 20m
> Remaining Estimate: 0h
>
> When large number of partitions (>20K) are processed, ColStatsProcessor runs
> into DB issues.
> {{ db.setPartitionColumnStatistics(request);}} gets stuck for hours together
> and in some cases postgres stops processing.
> It would be good to introduce small batches for stats gathering in
> ColStatsProcessor instead of bulk update.
> Ref:
> https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/stats/ColStatsProcessor.java#L181
> https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/stats/ColStatsProcessor.java#L199
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