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The following commit(s) were added to refs/heads/master by this push:
new 326f311 HIVE-22906: Redundant checkLock Mutex blocks concurrent Lock
requests (Denys Kuzmenko, reviewed by Peter Vary)
326f311 is described below
commit 326f31194c46d5c30bc1551a01ca1f4aad1231c2
Author: Denys Kuzmenko <dkuzme...@apache.org>
AuthorDate: Wed Mar 11 12:35:07 2020 +0100
HIVE-22906: Redundant checkLock Mutex blocks concurrent Lock requests
(Denys Kuzmenko, reviewed by Peter Vary)
---
.../hadoop/hive/metastore/txn/TxnHandler.java | 29 ++--------------------
1 file changed, 2 insertions(+), 27 deletions(-)
diff --git
a/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
b/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
index f53aebe..2995afa 100644
---
a/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
+++
b/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
@@ -4311,8 +4311,7 @@ abstract class TxnHandler implements TxnStore,
TxnStore.MutexAPI {
*/
@RetrySemantics.SafeToRetry("See @SafeToRetry")
private LockResponse checkLock(Connection dbConn, long extLockId)
- throws NoSuchLockException, NoSuchTxnException, TxnAbortedException,
MetaException, SQLException {
- TxnStore.MutexAPI.LockHandle handle = null;
+ throws NoSuchLockException, TxnAbortedException, MetaException,
SQLException {
Statement stmt = null;
ResultSet rs = null;
LockResponse response = new LockResponse();
@@ -4328,16 +4327,10 @@ abstract class TxnHandler implements TxnStore,
TxnStore.MutexAPI {
*/
boolean isPartOfDynamicPartitionInsert = true;
try {
- /**
- * checkLock() must be mutex'd against any other checkLock to make sure
2 conflicting locks
- * are not granted by parallel checkLock() calls.
- */
- handle = getMutexAPI().acquireLock(MUTEX_KEY.CheckLock.name());
List<LockInfo> locksBeingChecked = getLockInfoFromLockId(dbConn,
extLockId);//being acquired now
response.setLockid(extLockId);
-
LOG.debug("checkLock(): Setting savepoint. extLockId=" +
JavaUtils.lockIdToString(extLockId));
- Savepoint save = dbConn.setSavepoint();
+
StringBuilder query = new StringBuilder("SELECT \"HL_LOCK_EXT_ID\", " +
"\"HL_LOCK_INT_ID\", \"HL_DB\", \"HL_TABLE\", \"HL_PARTITION\",
\"HL_LOCK_STATE\", " +
"\"HL_LOCK_TYPE\", \"HL_TXNID\" FROM \"HIVE_LOCKS\" WHERE \"HL_DB\" IN
(");
@@ -4526,11 +4519,6 @@ abstract class TxnHandler implements TxnStore,
TxnStore.MutexAPI {
switch (lockAction) {
case WAIT:
if(!ignoreConflict(info, locks[i])) {
- /*we acquire all locks for a given query atomically; if 1
blocks, all go into (remain) in
- * Waiting state. wait() will undo any 'acquire()' which may
have happened as part of
- * this (metastore db) transaction and then we record which
lock blocked the lock
- * we were testing ('info').*/
- wait(dbConn, save);
String sqlText = "UPDATE \"HIVE_LOCKS\"" +
" SET \"HL_BLOCKEDBY_EXT_ID\"=" + locks[i].extLockId +
", \"HL_BLOCKEDBY_INT_ID\"=" + locks[i].intLockId +
@@ -4565,9 +4553,6 @@ abstract class TxnHandler implements TxnStore,
TxnStore.MutexAPI {
response.setState(LockState.ACQUIRED);
} finally {
close(rs, stmt, null);
- if(handle != null) {
- handle.releaseLocks();
- }
}
return response;
}
@@ -4645,16 +4630,6 @@ abstract class TxnHandler implements TxnStore,
TxnStore.MutexAPI {
(desiredLock.txnId == 0 && desiredLock.extLockId ==
existingLock.extLockId);
}
- private void wait(Connection dbConn, Savepoint save) throws SQLException {
- // Need to rollback because we did a select that acquired locks but we
didn't
- // actually update anything. Also, we may have locked some locks as
- // acquired that we now want to not acquire. It's ok to rollback because
- // once we see one wait, we're done, we won't look for more.
- // Only rollback to savepoint because we want to commit our heartbeat
- // changes.
- LOG.debug("Going to rollback to savepoint");
- dbConn.rollback(save);
- }
/**
* Heartbeats on the lock table. This commits, so do not enter it with any
state.
* Should not be called on a lock that belongs to transaction.
