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comparison src/main/java/org/monetdb/jdbc/MonetConnection.java @ 472:0e21097f438b

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Reduce the number of MonetDatabaseMetaData objects created via getMetaData() to maximum 1 per connection as it can be reused.
author Martin van Dinther <martin.van.dinther@monetdbsolutions.com>
date Fri, 30 Apr 2021 17:23:16 +0200 (2021-04-30)
parents 3dfcd06fd8ba
children d414e5c4470c
comparison
equal deleted inserted replaced
471:e14e81b8044e 472:0e21097f438b
145 private boolean treatClobAsVarChar = true; // turned on by default for optimal performance (from JDBC Driver release 2.30 onwards) 145 private boolean treatClobAsVarChar = true; // turned on by default for optimal performance (from JDBC Driver release 2.30 onwards)
146 146
147 /** The last set query timeout on the server as used by Statement, PreparedStatement and CallableStatement */ 147 /** The last set query timeout on the server as used by Statement, PreparedStatement and CallableStatement */
148 protected int lastSetQueryTimeout; // 0 means no timeout, which is the default on the server 148 protected int lastSetQueryTimeout; // 0 means no timeout, which is the default on the server
149 149
150 /** A cache to reduce the number of DatabaseMetaData objects created by getMetaData() to maximum 1 per connection */
151 private DatabaseMetaData dbmd;
152
150 153
151 /** 154 /**
152 * Constructor of a Connection for MonetDB. At this moment the 155 * Constructor of a Connection for MonetDB. At this moment the
153 * current implementation limits itself to storing the given host, 156 * current implementation limits itself to storing the given host,
154 * database, username and password for later use by the 157 * database, username and password for later use by the
584 * @throws SQLException if the current language is not SQL 587 * @throws SQLException if the current language is not SQL
585 * @return a DatabaseMetaData object for this Connection object 588 * @return a DatabaseMetaData object for this Connection object
586 */ 589 */
587 @Override 590 @Override
588 public DatabaseMetaData getMetaData() throws SQLException { 591 public DatabaseMetaData getMetaData() throws SQLException {
592 // for debug: System.out.println("calling getMetaData()");
589 if (lang != LANG_SQL) 593 if (lang != LANG_SQL)
590 throw new SQLException("This method is only supported in SQL mode", "M0M04"); 594 throw new SQLException("This method is only supported in SQL mode", "M0M04");
591 595 if (dbmd == null) {
592 return new MonetDatabaseMetaData(this); 596 // first use, construct it once and reuse it for all next calls
597 dbmd = new MonetDatabaseMetaData(this);
598 }
599 return dbmd;
593 } 600 }
594 601
595 /** 602 /**
596 * Retrieves this Connection object's current transaction isolation 603 * Retrieves this Connection object's current transaction isolation
597 * level. 604 * level.