deniskuzZ commented on a change in pull request #1592:
URL: https://github.com/apache/hive/pull/1592#discussion_r514997057
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
##########
@@ -2228,38 +2235,45 @@ public void addWriteNotificationLog(AcidWriteEvent
acidWriteEvent)
public void performWriteSetGC() throws MetaException {
Connection dbConn = null;
Statement stmt = null;
- ResultSet rs = null;
try {
dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED);
stmt = dbConn.createStatement();
-
- long minOpenTxn;
- rs = stmt.executeQuery("SELECT MIN(\"TXN_ID\") FROM \"TXNS\" WHERE
\"TXN_STATE\"=" + TxnStatus.OPEN);
- if (!rs.next()) {
- throw new IllegalStateException("Scalar query returned no rows?!?!!");
- }
- minOpenTxn = rs.getLong(1);
- if (rs.wasNull()) {
- minOpenTxn = Long.MAX_VALUE;
- }
- long lowWaterMark = getOpenTxnTimeoutLowBoundaryTxnId(dbConn);
- /**
- * We try to find the highest transactionId below everything was
committed or aborted.
- * For that we look for the lowest open transaction in the TXNS and the
TxnMinTimeout boundary,
- * because it is guaranteed there won't be open transactions below that.
- */
- long commitHighWaterMark = Long.min(minOpenTxn, lowWaterMark + 1);
- LOG.debug("Perform WriteSet GC with minOpenTxn {}, lowWaterMark {}",
minOpenTxn, lowWaterMark);
+ long commitHighWaterMark = getMinOpenTxnIdWaterMark(dbConn);
Review comment:
Question to getOpenTxnTimeoutLowBoundaryTxnId. If we need min open txn
why we are doing:
SELECT MAX(TXN_ID) FROM TXNS WHERE TXN_STARTED < (sysdate -
openTxnTimeOutMillis)
shouldn't in be MIN() ?
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