Changeset: 19a5583a7b5f for monetdb-java URL: https://dev.monetdb.org/hg/monetdb-java?cmd=changeset;node=19a5583a7b5f Modified Files: ChangeLog src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java Branch: default Log Message:
Improved performance of ResultSetMetaData methods isAutoIncrement(),
getPrecision() and getScale() significant for columns of specific data types as
in some cases no costly meta data query is executed anymore.
diffs (truncated from 323 to 300 lines):
diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,9 @@
# This file is updated with Maddlog
* Thu Oct 8 2020 Martin van Dinther <martin.van.dint...@monetdbsolutions.com>
+- Improved performance of ResultSetMetaData methods isAutoIncrement(),
+ getPrecision() and getScale() significant for columns of specific data
+ types as in some cases no costly meta data query is executed anymore.
- The connection properties treat_clob_as_varchar and treat_blob_as_binary
are now set to true by default within the JDBC driver. This is done
as it results by default in less memory usage, (much) faster response
diff --git a/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
b/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
--- a/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
+++ b/src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
@@ -1324,21 +1324,35 @@ public class MonetResultSet
/**
* Indicates whether the designated column is
automatically numbered.
*
+ * This method is currently very expensive for BIGINT,
+ * INTEGER, SMALLINT and TINYINT result column types
+ * as it needs to retrieve the information from the
+ * database using an SQL meta data query.
+ *
* @param column the first column is 1, the second is
2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error
occurs
*/
@Override
public boolean isAutoIncrement(final int column) throws
SQLException {
- checkColumnIndexValidity(column);
- try {
- if (_is_fetched[column] != true) {
- fetchColumnInfo(column);
- }
- return _isAutoincrement[column];
- } catch (IndexOutOfBoundsException e) {
- throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
+ // only few integer types can be auto
incrementable in MonetDB
+ // see:
https://www.monetdb.org/Documentation/SQLReference/DataTypes/SerialDatatypes
+ switch (getColumnType(column)) {
+ case Types.BIGINT:
+ case Types.INTEGER:
+ case Types.SMALLINT:
+ case Types.TINYINT:
+ try {
+ if (_is_fetched[column]
!= true) {
+
fetchColumnInfo(column);
+ }
+ return
_isAutoincrement[column];
+ } catch
(IndexOutOfBoundsException e) {
+ throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
+ }
}
+
+ return false;
}
/**
@@ -1414,14 +1428,14 @@ public class MonetResultSet
public boolean isSigned(final int column) throws
SQLException {
// we can hardcode this, based on the colum type
switch (getColumnType(column)) {
- case Types.NUMERIC:
- case Types.DECIMAL:
case Types.TINYINT:
case Types.SMALLINT:
case Types.INTEGER:
case Types.REAL:
case Types.FLOAT:
case Types.DOUBLE:
+ case Types.DECIMAL:
+ case Types.NUMERIC:
return true;
case Types.BIGINT:
final String monettype =
getColumnTypeName(column);
@@ -1434,10 +1448,10 @@ public class MonetResultSet
return true;
// All other types should return false
// case Types.BOOLEAN:
- // case Types.DATE:
- // case Types.TIME:
+ // case Types.DATE: // can year be
negative?
+ // case Types.TIME: // can time be
negative?
// case Types.TIME_WITH_TIMEZONE:
- // case Types.TIMESTAMP:
+ // case Types.TIMESTAMP: // can year be
negative?
// case Types.TIMESTAMP_WITH_TIMEZONE:
default:
return false;
@@ -1516,10 +1530,20 @@ public class MonetResultSet
}
/**
- * Get the designated column's number of decimal digits.
- * This method is currently very expensive as it needs
to
- * retrieve the information from the database using an
SQL
- * query.
+ * Get the designated column's specified column size.
+ * For numeric data, this is the maximum precision.
+ * For character data, this is the length in characters.
+ * For datetime datatypes, this is the length in
characters
+ * of the String representation (assuming the maximum
+ * allowed precision of the fractional seconds
component).
+ * For binary data, this is the length in bytes.
+ * For the ROWID datatype, this is the length in bytes.
+ * 0 is returned for data types where the column size
is not applicable.
+ *
+ * This method is currently very expensive for DECIMAL,
NUMERIC
+ * CHAR, VARCHAR, CLOB, BLOB, VARBINARY and BINARY
result
+ * column types as it needs to retrieve the information
+ * from the database using an SQL meta data query.
*
* @param column the first column is 1, the second is
2, ...
* @return precision
@@ -1527,73 +1551,76 @@ public class MonetResultSet
*/
@Override
public int getPrecision(final int column) throws
SQLException {
- checkColumnIndexValidity(column);
- try {
- if (_is_fetched[column] != true) {
- fetchColumnInfo(column);
- }
- 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:
+ final int tpe = getColumnType(column);
+ switch (tpe) {
+ case Types.BIGINT:
+ return 19;
+ case Types.INTEGER:
+ return 10;
+ case Types.SMALLINT:
+ return 5;
+ case Types.TINYINT:
+ return 3;
+ case Types.REAL:
+ return 7;
+ case Types.FLOAT:
+ case Types.DOUBLE:
+ return 15;
+
+ case Types.DECIMAL:
+ case Types.NUMERIC:
+ // these data types do not have
a fixed precision, max precision however is 38
+ // we need to fetch the defined
precision with an SQL query !
+ 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.BINARY:
+ case Types.VARBINARY:
+ case Types.BLOB:
+ // these data types also do not
have a fixed length
+ try {
+ if (_is_fetched[column]
!= true) {
+
fetchColumnInfo(column);
+ }
+ if (_precision[column]
== 0) {
+ // apparently
no precision or max length could be fetched
+ // use
columnDisplaySize() value as alternative
_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.BOOLEAN:
-
_precision[column] = 5;
- break;
- case Types.DATE:
-
_precision[column] = 10;
- break;
- case Types.TIME:
- case
Types.TIME_WITH_TIMEZONE:
-
_precision[column] = 8;
- break;
- case Types.TIMESTAMP:
- case
Types.TIMESTAMP_WITH_TIMEZONE:
-
_precision[column] = 19;
- break;
- default:
-
_precision[column] = 30;
- break;
+ if (tpe ==
Types.BLOB || tpe == Types.VARBINARY || tpe == Types.BINARY)
+ //
These expect number of bytes, not number of hex chars
+
_precision[column] = (_precision[column] / 2) +1;
+ }
+ return
_precision[column];
+ } catch
(IndexOutOfBoundsException e) {
+ throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
}
- }
- return _precision[column];
- } catch (IndexOutOfBoundsException e) {
- throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
+ case Types.DATE:
+ return 10; // 2020-10-08
+ case Types.TIME:
+ return 15; //
21:51:34.399753
+ case Types.TIME_WITH_TIMEZONE:
+ return 21; //
21:51:34.399753+02:00
+ case Types.TIMESTAMP:
+ return 26; // 2020-10-08
21:51:34.399753
+ case Types.TIMESTAMP_WITH_TIMEZONE:
+ return 32; // 2020-10-08
21:51:34.399753+02:00
+ case Types.BOOLEAN:
+ return 1;
+ default:
+ // All other types should
return 0
+ return 0;
}
}
/**
* Gets the designated column's number of digits to
right of
- * the decimal point. This method is currently very
- * expensive as it needs to retrieve the information
from
- * the database using an SQL query.
+ * the decimal point.
+ * 0 is returned for data types where the scale is not
applicable.
+ *
+ * This method is currently very expensive for DECIMAL
and NUMERIC
+ * result column types as it needs to retrieve the
information
+ * from the database using an SQL meta data query.
*
* @param column the first column is 1, the second is
2, ...
* @return scale
@@ -1601,25 +1628,56 @@ public class MonetResultSet
*/
@Override
public int getScale(final int column) throws
SQLException {
- checkColumnIndexValidity(column);
- try {
- if (_is_fetched[column] != true) {
- fetchColumnInfo(column);
- }
- return _scale[column];
- } catch (IndexOutOfBoundsException e) {
- throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
+ switch (getColumnType(column)) {
+ case Types.DECIMAL:
+ case Types.NUMERIC:
+ // these data types may have a
scale, max scale is 38
+ try {
+ if (_is_fetched[column]
!= true) {
+
fetchColumnInfo(column);
+ }
+ return _scale[column];
+ } catch
(IndexOutOfBoundsException e) {
+ throw
MonetResultSet.newSQLInvalidColumnIndexException(column);
+ }
+ case Types.TIME:
+ case Types.TIME_WITH_TIMEZONE:
+ case Types.TIMESTAMP:
+ case Types.TIMESTAMP_WITH_TIMEZONE:
+ // support microseconds, so
scale 6
+ return 6; //
21:51:34.399753
+ // All other types should return 0
+ // case Types.BIGINT:
+ // case Types.INTEGER:
+ // case Types.SMALLINT:
+ // case Types.TINYINT:
+ // case Types.REAL:
+ // case Types.FLOAT:
+ // case Types.DOUBLE:
+ // 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.BINARY:
+ // case Types.VARBINARY:
+ // case Types.BLOB:
+ // case Types.DATE:
+ // case Types.BOOLEAN:
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