diff options
Diffstat (limited to 'src/interfaces/jdbc/org/postgresql/Connection.java')
| -rw-r--r-- | src/interfaces/jdbc/org/postgresql/Connection.java | 118 |
1 files changed, 86 insertions, 32 deletions
diff --git a/src/interfaces/jdbc/org/postgresql/Connection.java b/src/interfaces/jdbc/org/postgresql/Connection.java index 7c6fb0adba5..1aa7be13f16 100644 --- a/src/interfaces/jdbc/org/postgresql/Connection.java +++ b/src/interfaces/jdbc/org/postgresql/Connection.java @@ -11,7 +11,7 @@ import org.postgresql.util.*; import org.postgresql.core.Encoding; /** - * $Id: Connection.java,v 1.21 2001/07/30 14:51:19 momjian Exp $ + * $Id: Connection.java,v 1.22 2001/08/04 19:32:04 momjian Exp $ * * This abstract class is used by org.postgresql.Driver to open either the JDBC1 or * JDBC2 versions of the Connection class. @@ -37,6 +37,9 @@ public abstract class Connection */ private Encoding encoding = Encoding.defaultEncoding(); + private String dbVersionLong; + private String dbVersionNumber; + public boolean CONNECTION_OK = true; public boolean CONNECTION_BAD = false; @@ -262,18 +265,19 @@ public abstract class Connection // used, so we denote this with 'UNKNOWN'. final String encodingQuery = - "select case when pg_encoding_to_char(1) = 'SQL_ASCII' then 'UNKNOWN' else getdatabaseencoding() end"; + "case when pg_encoding_to_char(1) = 'SQL_ASCII' then 'UNKNOWN' else getdatabaseencoding() end"; // Set datestyle and fetch db encoding in a single call, to avoid making // more than one round trip to the backend during connection startup. java.sql.ResultSet resultSet = - ExecSQL("set datestyle to 'ISO'; " + encodingQuery); + ExecSQL("set datestyle to 'ISO'; select version(), " + encodingQuery + ";"); if (! resultSet.next()) { throw new PSQLException("postgresql.con.failed", "failed getting backend encoding"); } - dbEncoding = resultSet.getString(1); + dbVersionLong = resultSet.getString(1); + dbEncoding = resultSet.getString(2); encoding = Encoding.getEncoding(dbEncoding, info.getProperty("charSet")); // Initialise object handling @@ -904,8 +908,7 @@ public abstract class Connection if (autoCommit) ExecSQL("end"); else { - ExecSQL("begin"); - doIsolationLevel(); + ExecSQL("begin; " + getIsolationLevelSQL()); } this.autoCommit = autoCommit; } @@ -934,11 +937,7 @@ public abstract class Connection public void commit() throws SQLException { if (autoCommit) return; - ExecSQL("commit"); - autoCommit = true; - ExecSQL("begin"); - doIsolationLevel(); - autoCommit = false; + ExecSQL("commit; begin; " + getIsolationLevelSQL()); } /** @@ -952,11 +951,7 @@ public abstract class Connection public void rollback() throws SQLException { if (autoCommit) return; - ExecSQL("rollback"); - autoCommit = true; - ExecSQL("begin"); - doIsolationLevel(); - autoCommit = false; + ExecSQL("rollback; begin; " + getIsolationLevelSQL()); } /** @@ -988,7 +983,7 @@ public abstract class Connection /** * You can call this method to try to change the transaction * isolation level using one of the TRANSACTION_* values. - * + * * <B>Note:</B> setTransactionIsolation cannot be called while * in the middle of a transaction * @@ -999,29 +994,67 @@ public abstract class Connection * @see java.sql.DatabaseMetaData#supportsTransactionIsolationLevel */ public void setTransactionIsolation(int level) throws SQLException { - isolationLevel = level; - doIsolationLevel(); + //In 7.1 and later versions of the server it is possible using + //the "set session" command to set this once for all future txns + //however in 7.0 and prior versions it is necessary to set it in + //each transaction, thus adding complexity below. + //When we decide to drop support for servers older than 7.1 + //this can be simplified + isolationLevel = level; + String isolationLevelSQL; + switch(isolationLevel) { + case java.sql.Connection.TRANSACTION_READ_COMMITTED: + if (haveMinimumServerVersion("7.1")) { + isolationLevelSQL = "SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL READ COMMITTED"; + } else { + isolationLevelSQL = getIsolationLevelSQL(); + } + break; + + case java.sql.Connection.TRANSACTION_SERIALIZABLE: + if (haveMinimumServerVersion("7.1")) { + isolationLevelSQL = "SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL SERIALIZABLE"; + } else { + isolationLevelSQL = getIsolationLevelSQL(); + } + break; + + default: + throw new PSQLException("postgresql.con.isolevel",new Integer(isolationLevel)); + } + ExecSQL(isolationLevelSQL); } /** * Helper method used by setTransactionIsolation(), commit(), rollback() - * and setAutoCommit(). This sets the current isolation level. + * and setAutoCommit(). This returns the SQL string needed to + * set the isolation level for a transaction. In 7.1 and later it + * is possible to set a default isolation level that applies to all + * future transactions, this method is only necesary for 7.0 and older + * servers, and should be removed when support for these older + * servers are dropped */ - protected void doIsolationLevel() throws SQLException { + protected String getIsolationLevelSQL() throws SQLException { + //7.1 and higher servers have a default specified so + //no additional SQL is required to set the isolation level + if (haveMinimumServerVersion("7.1")) { + return ""; + } String q = "SET TRANSACTION ISOLATION LEVEL"; switch(isolationLevel) { case java.sql.Connection.TRANSACTION_READ_COMMITTED: - ExecSQL(q + " READ COMMITTED"); - return; + q = q + " READ COMMITTED"; + break; case java.sql.Connection.TRANSACTION_SERIALIZABLE: - ExecSQL(q + " SERIALIZABLE"); - return; + q = q + " SERIALIZABLE"; + break; default: throw new PSQLException("postgresql.con.isolevel",new Integer(isolationLevel)); } + return q; } /** @@ -1033,13 +1066,7 @@ public abstract class Connection */ public void setCatalog(String catalog) throws SQLException { - if(catalog!=null && !catalog.equals(PG_DATABASE)) { - close(); - Properties info=new Properties(); - info.setProperty("user", PG_USER); - info.setProperty("password", PG_PASSWORD); - openConnection(PG_HOST, PG_PORT, info, catalog, this_url, this_driver); - } + //no-op } /** @@ -1095,4 +1122,31 @@ public abstract class Connection return sql; } + /** + * What is the version of the server + * + * @return the database version + * @exception SQLException if a database access error occurs + */ + public String getDBVersionNumber() throws SQLException + { + if(dbVersionNumber == null) { + StringTokenizer versionParts = new StringTokenizer(dbVersionLong); + versionParts.nextToken(); /* "PostgreSQL" */ + dbVersionNumber = versionParts.nextToken(); /* "X.Y.Z" */ + } + return dbVersionNumber; + } + + public boolean haveMinimumServerVersion(String ver) throws SQLException + { + if (getDBVersionNumber().compareTo(ver)>=0) + return true; + else + return false; + } + + + } + |