[hive] branch master updated: HIVE-25522: NullPointerException in TxnHandler (#2647)

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sunchao pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/hive.git


The following commit(s) were added to refs/heads/master by this push:
     new c8a0b6f  HIVE-25522: NullPointerException in TxnHandler (#2647)
c8a0b6f is described below

commit c8a0b6f4887edc2f33ed5d2c77c8baf9c0bbd11c
Author: Szehon Ho <sz...@gmail.com>
AuthorDate: Sat Nov 6 12:52:39 2021 -0700

    HIVE-25522: NullPointerException in TxnHandler (#2647)
---
 .../hadoop/hive/metastore/txn/TxnHandler.java      | 41 +++++++++++++---------
 1 file changed, 24 insertions(+), 17 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 9abe615..8b05e93 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
@@ -368,33 +368,36 @@ abstract class TxnHandler implements TxnStore, TxnStore.MutexAPI {
   public void setConf(Configuration conf){
     this.conf = conf;
 
+    int maxPoolSize = MetastoreConf.getIntVar(conf, ConfVars.CONNECTION_POOLING_MAX_CONNECTIONS);
+    long getConnectionTimeoutMs = 30000;
     synchronized (TxnHandler.class) {
       if (connPool == null) {
-        Connection dbConn = null;
-        // Set up the JDBC connection pool
-        try {
-          int maxPoolSize = MetastoreConf.getIntVar(conf, ConfVars.CONNECTION_POOLING_MAX_CONNECTIONS);
-          long getConnectionTimeoutMs = 30000;
-          connPool = setupJdbcConnectionPool(conf, maxPoolSize, getConnectionTimeoutMs);
-          /*the mutex pools should ideally be somewhat larger since some operations require 1
+        connPool = setupJdbcConnectionPool(conf, maxPoolSize, getConnectionTimeoutMs);
+      }
+
+      if (connPoolMutex == null) {
+        /*the mutex pools should ideally be somewhat larger since some operations require 1
            connection from each pool and we want to avoid taking a connection from primary pool
            and then blocking because mutex pool is empty.  There is only 1 thread in any HMS trying
            to mutex on each MUTEX_KEY except MUTEX_KEY.CheckLock.  The CheckLock operation gets a
            connection from connPool first, then connPoolMutex.  All others, go in the opposite
            order (not very elegant...).  So number of connection requests for connPoolMutex cannot
            exceed (size of connPool + MUTEX_KEY.values().length - 1).*/
-          connPoolMutex = setupJdbcConnectionPool(conf, maxPoolSize + MUTEX_KEY.values().length, getConnectionTimeoutMs);
-          dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED);
+        connPoolMutex = setupJdbcConnectionPool(conf, maxPoolSize + MUTEX_KEY.values().length, getConnectionTimeoutMs);
+      }
+
+      if (dbProduct == null) {
+        try (Connection dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED)) {
           determineDatabaseProduct(dbConn);
-          sqlGenerator = new SQLGenerator(dbProduct, conf);
         } catch (SQLException e) {
-          String msg = "Unable to instantiate JDBC connection pooling, " + e.getMessage();
-          LOG.error(msg);
+          LOG.error("Unable to determine database product", e);
           throw new RuntimeException(e);
-        } finally {
-          closeDbConn(dbConn);
         }
       }
+
+      if (sqlGenerator == null) {
+        sqlGenerator = new SQLGenerator(dbProduct, conf);
+      }
     }
 
     numOpenTxns = Metrics.getOrCreateGauge(MetricsConstants.NUM_OPEN_TXNS);
@@ -4611,7 +4614,6 @@ abstract class TxnHandler implements TxnStore, TxnStore.MutexAPI {
 
 
   private void determineDatabaseProduct(Connection conn) {
-    if (dbProduct != null) return;
     try {
       String s = conn.getMetaData().getDatabaseProductName();
       dbProduct = DatabaseProduct.determineDatabaseProduct(s, conf);
@@ -5575,10 +5577,15 @@ abstract class TxnHandler implements TxnStore, TxnStore.MutexAPI {
     }
   }
 
-  private static synchronized DataSource setupJdbcConnectionPool(Configuration conf, int maxPoolSize, long getConnectionTimeoutMs) throws SQLException {
+  private synchronized static DataSource setupJdbcConnectionPool(Configuration conf, int maxPoolSize, long getConnectionTimeoutMs) {
     DataSourceProvider dsp = DataSourceProviderFactory.tryGetDataSourceProviderOrNull(conf);
     if (dsp != null) {
-      return dsp.create(conf);
+      try {
+        return dsp.create(conf);
+      } catch (SQLException e) {
+        LOG.error("Unable to instantiate JDBC connection pooling", e);
+        throw new RuntimeException(e);
+      }
     } else {
       String connectionPooler = MetastoreConf.getVar(conf, ConfVars.CONNECTION_POOLING_TYPE).toLowerCase();
       if ("none".equals(connectionPooler)) {