Changeset: cc472ea19b3f for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java?cmd=changeset;node=cc472ea19b3f
Modified Files:
src/main/java/nl/cwi/monetdb/jdbc/MonetResultSet.java
Branch: default
Log Message:
Optimize ResultSetMetaData by delaying creating of a new DatabaseMetaData
object till when it is actually needed.
diffs (60 lines):
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
@@ -1256,7 +1256,7 @@ public class MonetResultSet
private final int[] _isNullable = new int[array_size];
private final boolean[] _isAutoincrement = new
boolean[array_size];
private final Connection conn =
getStatement().getConnection();
- private final DatabaseMetaData dbmd =
conn.getMetaData();
+ private DatabaseMetaData dbmd = null; // it will be
assigned at first need and reused for other columns
/**
* A private utility method to check validity of column
index number
@@ -1283,6 +1283,13 @@ public class MonetResultSet
_isNullable[column] = columnNullableUnknown;
_isAutoincrement[column] = false;
+ if (dbmd == null) {
+ // first time usage
+ dbmd = conn.getMetaData();
+ if (dbmd == null)
+ return;
+ }
+
// we will only call dbmd.getColumns() when we
have a specific schema name and table name and column name
final String schName = getSchemaName(column);
if (schName != null && !schName.isEmpty()) {
@@ -1290,21 +1297,19 @@ public class MonetResultSet
if (tblName != null &&
!tblName.isEmpty()) {
final String colName =
getColumnName(column);
if (colName != null &&
!colName.isEmpty()) {
- if (dbmd != null) {
- // for
precision, scale, isNullable and isAutoincrement we query the information from
data dictionary
- final 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"
-
final String strVal = colInfo.getString(23); // col 23 is "IS_AUTOINCREMENT"
-
if (strVal != null && "YES".equals(strVal))
-
_isAutoincrement[column] = true;
- }
-
colInfo.close(); // close the resultset to release resources
+ // for precision,
scale, isNullable and isAutoincrement we query the information from data
dictionary
+ final 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"
+ final
String strVal = colInfo.getString(23); // col 23 is "IS_AUTOINCREMENT"
+ if
(strVal != null && "YES".equals(strVal))
+
_isAutoincrement[column] = true;
}
+
colInfo.close(); // close the resultset to release resources
}
}
}
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