gatorblue commented on a change in pull request #1470:
URL: https://github.com/apache/hive/pull/1470#discussion_r491132388
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/DatabaseProduct.java
##########
@@ -20,71 +20,646 @@
import java.sql.SQLException;
import java.sql.SQLTransactionRollbackException;
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
-/** Database product infered via JDBC. */
-public enum DatabaseProduct {
- DERBY, MYSQL, POSTGRES, ORACLE, SQLSERVER, OTHER;
+import org.apache.hadoop.conf.Configurable;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hive.metastore.api.MetaException;
+import org.apache.hadoop.hive.metastore.conf.MetastoreConf;
+import org.apache.hadoop.hive.metastore.conf.MetastoreConf.ConfVars;
+import org.apache.hadoop.util.ReflectionUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+/** Database product inferred via JDBC. Encapsulates all SQL logic associated
with
+ * the database product.
+ * This class is a singleton, which is instantiated the first time
+ * method determineDatabaseProduct is invoked.
+ * Tests that need to create multiple instances can use the reset method
+ * */
+public class DatabaseProduct implements Configurable {
+ static final private Logger LOG =
LoggerFactory.getLogger(DatabaseProduct.class.getName());
+
+ private static enum DbType {DERBY, MYSQL, POSTGRES, ORACLE, SQLSERVER,
EXTERNAL, OTHER};
+ public DbType dbType;
+
+ // Singleton instance
+ private static DatabaseProduct theDatabaseProduct;
+
+ static {
+ final Configuration conf = MetastoreConf.newMetastoreConf();
+ // Check if we are using an external database product
+ boolean isExternal = MetastoreConf.getBoolVar(conf,
ConfVars.USE_CUSTOM_RDBMS);
+
+ if (isExternal) {
+ // The DatabaseProduct will be created by instantiating an external
class via
+ // reflection. The external class can override any method in the current
class
+ String className = MetastoreConf.getVar(conf,
ConfVars.CUSTOM_RDBMS_CLASSNAME);
+
+ if (className != null) {
+ try {
+ theDatabaseProduct = (DatabaseProduct)
+ ReflectionUtils.newInstance(Class.forName(className), conf);
+
+ theDatabaseProduct.dbType = DbType.EXTERNAL;
+ }catch (Exception e) {
+ LOG.warn("Unable to instantiate custom database product. Reverting
to default", e);
+ }
+ }
+ else {
+ LOG.warn("metastore.use.custom.database.product was set, " +
+ "but metastore.custom.database.product.classname was not.
Reverting to default");
+ }
+ }
+ }
+
+ /**
+ * Private constructor for singleton class
+ * @param id
+ */
+ private DatabaseProduct() {}
+
+ public static final String DERBY_NAME = "derby";
+ public static final String SQL_SERVER_NAME = "microsoft sql server";
+ public static final String MYSQL_NAME = "mysql";
+ public static final String POSTGRESQL_NAME = "postgresql";
+ public static final String ORACLE_NAME = "oracle";
+ public static final String OTHER_NAME = "other";
+
/**
* Determine the database product type
* @param productName string to defer database connection
* @return database product type
*/
- public static DatabaseProduct determineDatabaseProduct(String productName)
throws SQLException {
+ public static DatabaseProduct determineDatabaseProduct(String productName) {
+ DbType dbt;
+
if (productName == null) {
- return OTHER;
+ productName = OTHER_NAME;
}
+
productName = productName.toLowerCase();
- if (productName.contains("derby")) {
- return DERBY;
- } else if (productName.contains("microsoft sql server")) {
- return SQLSERVER;
- } else if (productName.contains("mysql")) {
- return MYSQL;
- } else if (productName.contains("oracle")) {
- return ORACLE;
- } else if (productName.contains("postgresql")) {
- return POSTGRES;
+
+ if (productName.contains(DERBY_NAME)) {
+ dbt = DbType.DERBY;
+ } else if (productName.contains(SQL_SERVER_NAME)) {
+ dbt = DbType.SQLSERVER;
+ } else if (productName.contains(MYSQL_NAME)) {
+ dbt = DbType.MYSQL;
+ } else if (productName.contains(ORACLE_NAME)) {
+ dbt = DbType.ORACLE;
+ } else if (productName.contains(POSTGRESQL_NAME)) {
+ dbt = DbType.POSTGRES;
} else {
- return OTHER;
+ dbt = DbType.OTHER;
}
+
+ // This method may be invoked by concurrent connections
+ synchronized (DatabaseProduct.class) {
+ if (theDatabaseProduct == null) {
+ theDatabaseProduct = new DatabaseProduct();
+ }
+
+ theDatabaseProduct.dbType = dbt;
+ }
+ return theDatabaseProduct;
+ }
+
+ public final boolean isDERBY() {
+ return dbType == DbType.DERBY;
+ }
+
+ public final boolean isMYSQL() {
+ return dbType == DbType.MYSQL;
}
- public static boolean isDeadlock(DatabaseProduct dbProduct, SQLException e) {
+ public final boolean isORACLE() {
+ return dbType == DbType.ORACLE;
+ }
+
+ public final boolean isSQLSERVER() {
+ return dbType == DbType.SQLSERVER;
+ }
+
+ public final boolean isPOSTGRES() {
+ return dbType == DbType.POSTGRES;
+ }
+
+ public final boolean isEXTERNAL() {
+ return dbType == DbType.EXTERNAL;
+ }
+
+ public final boolean isOTHER() {
+ return dbType == DbType.OTHER;
+ }
+
+ public boolean isDeadlock(SQLException e) {
return e instanceof SQLTransactionRollbackException
- || ((dbProduct == MYSQL || dbProduct == POSTGRES || dbProduct ==
SQLSERVER)
+ || ((isMYSQL() || isPOSTGRES() || isSQLSERVER() || isEXTERNAL())
&& "40001".equals(e.getSQLState()))
- || (dbProduct == POSTGRES && "40P01".equals(e.getSQLState()))
- || (dbProduct == ORACLE && (e.getMessage() != null &&
(e.getMessage().contains("deadlock detected")
+ || (isPOSTGRES() && "40P01".equals(e.getSQLState()))
+ || (isORACLE() && (e.getMessage() != null &&
(e.getMessage().contains("deadlock detected")
|| e.getMessage().contains("can't serialize access for this
transaction"))));
}
/**
* Whether the RDBMS has restrictions on IN list size (explicit, or poor
perf-based).
*/
- public static boolean needsInBatching(DatabaseProduct dbType) {
- return dbType == ORACLE || dbType == SQLSERVER;
+ protected boolean needsInBatching() {
+ return isORACLE() || isSQLSERVER();
}
/**
* Whether the RDBMS has a bug in join and filter operation order described
in DERBY-6358.
*/
- public static boolean hasJoinOperationOrderBug(DatabaseProduct dbType) {
- return dbType == DERBY || dbType == ORACLE || dbType == POSTGRES;
+ protected boolean hasJoinOperationOrderBug() {
+ return isDERBY() || isORACLE() || isPOSTGRES();
}
- public static String getHiveSchemaPostfix(DatabaseProduct dbType) {
+ public String getHiveSchemaPostfix() {
switch (dbType) {
case SQLSERVER:
return "mssql";
case DERBY:
case MYSQL:
case POSTGRES:
case ORACLE:
+ case EXTERNAL:
return dbType.name().toLowerCase();
case OTHER:
default:
return null;
}
}
+
+ public static void reset() {
Review comment:
:-) ... It's so that we don't fall into the assertion you suggested
right above (i.e. "Preconditions.checkState(this.dbType ==
getDbType(productName));").
There is a test in the Hive test suite that creates multiple instances of
DatabaseProduct for different databases, which fails unless the instance is
reset.
I had added the same assertion you suggested when I originally wrote the
code, but then removed it when I got bitten by the test. I was on the fence of
whether the assertion was useful or not, so I removed it. I now put it back,
along with the calls to reset() in the test.
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