SourabhBadhya commented on code in PR #4313:
URL: https://github.com/apache/hive/pull/4313#discussion_r1219121485
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standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/CompactionTxnHandler.java:
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@@ -92,6 +94,52 @@ class CompactionTxnHandler extends TxnHandler {
"DELETE FROM \"TXNS\" WHERE \"TXN_ID\" NOT IN (SELECT \"TC_TXNID\" FROM
\"TXN_COMPONENTS\") " +
"AND (\"TXN_STATE\" = " + TxnStatus.ABORTED + " OR \"TXN_STATE\" = "
+ TxnStatus.COMMITTED + ") " +
"AND \"TXN_ID\" < ?";
+
+ // Three inner sub-queries which are under union all and gets the max values
for corresponding db, table, partition.
+ private static final String SELECT_ABORTS_WITH_MIN_OPEN_WRITETXN_QUERY =
+ "SELECT \"DB\", \"TBL\", \"PART\", MAX(\"MIN_TXN_START_TIME\"),
MAX(\"ABORTED_TXN_COUNT\"), " +
+ " MAX(\"MIN_OPEN_WRITE_TXNID\"), MAX(\"RETRY_RETENTION\"),
MAX(\"RETRY_RECORD_CHECK\") FROM ( " +
+ // First sub-query - Gets the aborted txns with min txn start time,
number of aborted txns
+ // for corresponding db, table, partition.
+ " SELECT \"TC_DATABASE\" AS \"DB\", \"TC_TABLE\" AS \"TBL\",
\"TC_PARTITION\" AS \"PART\", " +
+ " MIN(\"TXN_STARTED\") AS \"MIN_TXN_START_TIME\", COUNT(*) AS
\"ABORTED_TXN_COUNT\", " +
+ " 0 AS \"MIN_OPEN_WRITE_TXNID\", -1 AS \"RETRY_RETENTION\", 0 AS
\"RETRY_RECORD_CHECK\" " +
Review Comment:
As discussed, implemented a left join query rather than union all since
union all based query can fetch large number of records in the result set when
there are no aborted txns for a table/partition. Done.
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