Changeset: 95cf74c7f51c for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=95cf74c7f51c
Modified Files:
java/ChangeLog.Jun2016
java/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
java/tests/Test_Rmetadata.java
sql/jdbc/tests/Tests/Test_Rmetadata.stable.out
Branch: Jun2016
Log Message:
Fixed resource leak in ResultSetMetaData. It created and cached a ResultSet
object for each column but never closed the ResultSet objects.
diffs (truncated from 496 to 300 lines):
diff --git a/java/ChangeLog.Jun2016 b/java/ChangeLog.Jun2016
--- a/java/ChangeLog.Jun2016
+++ b/java/ChangeLog.Jun2016
@@ -1,6 +1,10 @@
# ChangeLog file for java
# This file is updated with Maddlog
+* Thu Apr 21 2016 Martin van Dinther <martin.van.dint...@monetdbsolutions.com>
+- Fixed resource leak in ResultSetMetaData. It created and cached a ResultSet
+ object for each column but never closed the ResultSet objects.
+
* Thu Mar 31 2016 Martin van Dinther <martin.van.dint...@monetdbsolutions.com>
- Corrected DatabaseMetaData methods which accept a catalog filter argument.
Those methods will now filter the results on the specified catalog name,
diff --git a/java/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
b/java/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
--- a/java/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
+++ b/java/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
@@ -21,6 +21,7 @@ import java.net.URL;
import java.sql.Array;
import java.sql.Blob;
import java.sql.Clob;
+import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.NClob;
import java.sql.Ref;
@@ -683,7 +684,7 @@ public class MonetResultSet extends Mone
* @throws SQLException if there is no such column
*/
@Override
- public boolean getBoolean(int columnIndex) throws SQLException{
+ public boolean getBoolean(int columnIndex) throws SQLException {
switch (getJavaType(types[columnIndex - 1])) {
case Types.TINYINT:
case Types.SMALLINT:
@@ -1081,11 +1082,63 @@ public class MonetResultSet extends Mone
public ResultSetMetaData getMetaData() {
// return inner class which implements the ResultSetMetaData
interface
return new rsmdw() {
- // for the more expensive methods, we provide a simple
cache
- // for the most expensive part; getting the ResultSet
which
- // contains the data
+ // for the more expensive methods (getPrecision(),
getScale(), isNullable()), we provide a simple cache
+ // caches to store precision, scale and isNullable
values from getColumns()
+ private boolean[] _is_fetched = new
boolean[columns.length +1];
+ private int[] _precision = new
int[columns.length +1];
+ private int[] _scale = new
int[columns.length +1];
+ private int[] _isNullable = new
int[columns.length +1];
+ private Connection conn = null;
private DatabaseMetaData dbmd = null;
- private ResultSet[] colrs = new
ResultSet[columns.length];
+
+ /**
+ * A private method to fetch the precision, scale and
isNuallble value for a fully qualified column.
+ * As md.getColumns() is an expensive method we call it
only once per column
+ * and cache the precision, scale and isNullable values
in the above array chaches.
+ * Also we only call md.getColumns() when we have a non
empty schema name and table name and column name.
+ */
+ private void fetchColumnInfo(int column) throws
SQLException
+ {
+ if (column <= 0 || column > columns.length)
+ throw new SQLException("No such column
" + column, "M1M05");
+
+ _is_fetched[column] = true;
+ _precision[column] = 0;
+ _scale[column] = 0;
+ _isNullable[column] = columnNullableUnknown;
+
+ // we can only call dbmd.getColumns() when we
have a specific schema name and table name and column name
+ String schName = getSchemaName(column);
+ if (schName != null && !"".equals(schName)) {
+ String tblName = getTableName(column);
+ if (tblName != null &&
!"".equals(tblName)) {
+ String colName =
getColumnName(column);
+ if (colName != null &&
!"".equals(colName)) {
+ if (conn == null) {
+ // first time,
get a Connection object and cache it for all next columns
+ conn =
getStatement().getConnection();
+ }
+ if (conn != null &&
dbmd == null) {
+ // first time,
get a MetaData object and cache it for all next columns
+ dbmd =
conn.getMetaData();
+ }
+ if (dbmd != null) {
+ // for
precision, scale and isNullable we query the information from data dictionary
+ ResultSet
colInfo = dbmd.getColumns(null, schName, tblName, colName);
+ if (colInfo !=
null) {
+ // we
expect exactly one row in the resultset
+ if
(colInfo.next()) {
+
_precision[column] = colInfo.getInt(7); // col 7 is "COLUMN_SIZE"
+
_scale[column] = colInfo.getInt(9); // col 9 is "DECIMAL_DIGITS"
+
_isNullable[column] = colInfo.getInt(11); // col 11 is "NULLABLE"
+ }
+
colInfo.close(); // close the resultset to release resources
+ }
+ }
+ }
+ }
+ }
+ }
/**
* Returns the number of columns in this ResultSet
object.
@@ -1098,8 +1151,7 @@ public class MonetResultSet extends Mone
}
/**
- * Indicates whether the designated column is
automatically
- * numbered, thus read-only.
+ * Indicates whether the designated column is
automatically numbered.
*
* @param column the first column is 1, the second is
2, ...
* @return true if so; false otherwise
@@ -1118,15 +1170,21 @@ public class MonetResultSet extends Mone
}
/**
- * Indicates whether a column's case matters. This
holds for all
- * columns in MonetDB resultsets since the mapping is
done case
- * insensitive, therefore this method will always
return false.
+ * Indicates whether a column's case matters.
*
* @param column the first column is 1, the second is
2, ...
- * @returns false
+ * @returns true for all character string columns else
false
*/
@Override
- public boolean isCaseSensitive(int column) {
+ public boolean isCaseSensitive(int column) throws
SQLException {
+ switch (getColumnType(column)) {
+ case Types.CHAR:
+ case Types.VARCHAR:
+ case Types.LONGVARCHAR: // MonetDB
doesn't use type LONGVARCHAR, it's here for completeness
+ case Types.CLOB:
+ return true;
+ }
+
return false;
}
@@ -1290,19 +1348,62 @@ public class MonetResultSet extends Mone
*/
@Override
public int getPrecision(int column) throws SQLException
{
- int precision = 0;
- try {
- ResultSet col =
getColumnResultSet(column);
-
- // the result has either zero or one
results, as the
- // schema, table and column should be
unique...
- if (col.next())
- precision =
col.getInt("COLUMN_SIZE");
- } catch (NullPointerException npe) {
- /* do nothing */
+ if (_is_fetched[column] != true) {
+ fetchColumnInfo(column);
}
-
- return precision;
+ if (_precision[column] == 0) {
+ // apparently no precision could be
fetched
+ // use columnDisplaySize() value for
variable length data types
+ switch (getColumnType(column)) {
+ case Types.CHAR:
+ case Types.VARCHAR:
+ case Types.LONGVARCHAR: //
MonetDB doesn't use type LONGVARCHAR, it's here for completeness
+ case Types.CLOB:
+ case Types.BLOB:
+ case Types.NUMERIC:
+ case Types.DECIMAL:
+ _precision[column] =
getColumnDisplaySize(column);
+ break;
+ case Types.TINYINT:
+ _precision[column] = 3;
+ break;
+ case Types.SMALLINT:
+ _precision[column] = 5;
+ break;
+ case Types.INTEGER:
+ _precision[column] = 10;
+ break;
+ case Types.BIGINT:
+ _precision[column] = 19;
+ break;
+ case Types.REAL:
+ _precision[column] = 7;
+ break;
+ case Types.FLOAT:
+ case Types.DOUBLE:
+ _precision[column] = 15;
+ break;
+ case Types.BIT: // MonetDB
doesn't use type BIT, it's here for completeness
+ _precision[column] = 1;
+ break;
+ case Types.BOOLEAN:
+ _precision[column] = 5;
+ break;
+ case Types.DATE:
+ _precision[column] = 10;
+ break;
+ case Types.TIME:
+ _precision[column] = 8;
+ break;
+ case Types.TIMESTAMP:
+ _precision[column] = 19;
+ break;
+ default:
+ _precision[column] = 30;
+ break;
+ }
+ }
+ return _precision[column];
}
/**
@@ -1317,19 +1418,10 @@ public class MonetResultSet extends Mone
*/
@Override
public int getScale(int column) throws SQLException {
- int scale = 0;
- try {
- ResultSet col =
getColumnResultSet(column);
-
- // the result has either zero or one
results, as the
- // schema, table and column should be
unique...
- if (col.next())
- scale =
col.getInt("DECIMAL_DIGITS");
- } catch (NullPointerException npe) {
- /* do nothing */
+ if (_is_fetched[column] != true) {
+ fetchColumnInfo(column);
}
-
- return scale;
+ return _scale[column];
}
/**
@@ -1339,30 +1431,20 @@ public class MonetResultSet extends Mone
* an SQL query.
*
* @param column the first column is 1, the second is
2, ...
- * @return scale
+ * @return the nullability status of the given column;
one of columnNoNulls, columnNullable or columnNullableUnknown
* @throws SQLException if a database access error
occurs
*/
@Override
public int isNullable(int column) throws SQLException {
- int ret = columnNullableUnknown;
- try {
- ResultSet col =
getColumnResultSet(column);
-
- // the result has either zero or one
results, as the
- // schema, table and column should be
unique...
- if (col.next())
- ret = col.getInt("NULLABLE");
- } catch (NullPointerException npe) {
- /* do nothing */
+ if (_is_fetched[column] != true) {
+ fetchColumnInfo(column);
}
-
- return ret;
+ return _isNullable[column];
}
/**
* Gets the designated column's table's catalog name.
- * Because MonetDB handles only one catalog (dbfarm) at
a
- * time, the current one is the one we deal with here.
+ * MonetDB does not support the catalog naming concept
as in: catalog.schema.table naming scheme
*
* @param column the first column is 1, the second is
2, ...
* @return the name of the catalog for the table in
which the given
@@ -1370,11 +1452,8 @@ public class MonetResultSet extends Mone
*/
@Override
public String getCatalogName(int column) throws
SQLException {
- if (getTableName(column) != "") {
- return
getStatement().getConnection().getCatalog();
- } else {
- return "";
- }
+ return null; // MonetDB does NOT support
catalogs
+
}
/**
@@ -1432,17 +1511,22 @@ public class MonetResultSet extends Mone
@Override
public String getColumnClassName(int column) throws
SQLException {
try {
- Class type;
- Map map =
getStatement().getConnection().getTypeMap();
- if (map.containsKey(types[column - 1]))
{
- type =
(Class)map.get(types[column - 1]);
- } else {
- type =
getClassForType(getJavaType(types[column - 1]));
+ if (conn == null) {
+ // first time, get a Connection
object and cache it for all next columns
+ conn =
getStatement().getConnection();
_______________________________________________
checkin-list mailing list
checkin-list@monetdb.org
https://www.monetdb.org/mailman/listinfo/checkin-list
