Changeset: 6a6c86ac3232 for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java/rev/6a6c86ac3232
Modified Files:
src/main/java/org/monetdb/jdbc/MonetPreparedStatement.java
Branch: default
Log Message:
Optimised storing, setting and processing of parameter values in
MonetPreparedStatement.
It used to allocate an array to store parameter values potententially larger
than needed.
Also it needed to compute the array index position for each set parameter by
invoking getParamIdx(int) each time.
This overhead is now eliminated as the parameter values array size is in sync
with the parameter index numbers.
Also made the StringBuilder buffer to construct the exec ###() statement
reusable, so much less objects are created.
diffs (278 lines):
diff --git a/src/main/java/org/monetdb/jdbc/MonetPreparedStatement.java
b/src/main/java/org/monetdb/jdbc/MonetPreparedStatement.java
--- a/src/main/java/org/monetdb/jdbc/MonetPreparedStatement.java
+++ b/src/main/java/org/monetdb/jdbc/MonetPreparedStatement.java
@@ -80,7 +80,8 @@ public class MonetPreparedStatement
private final int size;
private final int rscolcnt;
- private final String[] values;
+ private int paramCount = 0;
+ private final String[] paramValues;
/* placeholders for date/time pattern formats created once (only when
needed), used multiple times */
/** Format of a timestamp with RFC822 time zone */
@@ -139,7 +140,6 @@ public class MonetPreparedStatement
schema = new String[size];
table = new String[size];
column = new String[size];
- values = new String[size];
// fill the arrays
final ResultSet rs = super.getResultSet();
@@ -169,13 +169,17 @@ public class MonetPreparedStatement
schema[i] = rs.getString(schema_colnr);
table[i] = rs.getString(table_colnr);
column[i] = rs.getString(column_colnr);
+ // System.out.println("column " + i + " has
value: " + column[i]);
/* when column[i] != null it is a result column
of the prepared query, see getColumnIdx(int),
when column[i] == null it is a parameter for
the prepared statement, see getParamIdx(int). */
- // System.out.println("column " + i + " has
value: " + column[i]);
+ if (column[i] == null)
+ paramCount++;
}
rs.close();
}
+ paramValues = new String[paramCount + 1]; // parameters
start from 1
+
// PreparedStatements are by default poolable
poolable = true;
}
@@ -212,7 +216,7 @@ public class MonetPreparedStatement
schema = null;
table = null;
column = null;
- values = null;
+ paramValues = null;
id = -1;
size = -1;
rscolcnt = -1;
@@ -249,8 +253,8 @@ public class MonetPreparedStatement
*/
@Override
public void clearParameters() {
- for (int i = 0; i < size; i++) {
- values[i] = null;
+ for (int param = 1; param <= paramCount; param++) {
+ paramValues[param] = null;
}
}
@@ -785,17 +789,10 @@ public class MonetPreparedStatement
* object contains information.
*
* @return the number of parameters
- * @throws SQLException if a database access error
occurs
*/
@Override
- public int getParameterCount() throws SQLException {
- int cnt = 0;
-
- for (int i = 0; i < size; i++) {
- if (column[i] == null)
- cnt++;
- }
- return cnt;
+ public int getParameterCount() {
+ return paramCount;
}
/**
@@ -809,10 +806,9 @@ public class MonetPreparedStatement
* one of ParameterMetaData.parameterNoNulls,
* ParameterMetaData.parameterNullable, or
* ParameterMetaData.parameterNullableUnknown
- * @throws SQLException if a database access error
occurs
*/
@Override
- public int isNullable(final int param) throws
SQLException {
+ public int isNullable(final int param) {
return
ParameterMetaData.parameterNullableUnknown;
}
@@ -962,10 +958,9 @@ public class MonetPreparedStatement
* ParameterMetaData.parameterModeOut, or
* ParameterMetaData.parameterModeInOut
* ParameterMetaData.parameterModeUnknown.
- * @throws SQLException if a database access error
occurs
*/
@Override
- public int getParameterMode(final int param) throws
SQLException {
+ public int getParameterMode(final int param) {
return ParameterMetaData.parameterModeIn;
}
};
@@ -1263,7 +1258,7 @@ public class MonetPreparedStatement
@Override
public void setBytes(final int parameterIndex, final byte[] x) throws
SQLException {
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -1358,7 +1353,7 @@ public class MonetPreparedStatement
@Override
public void setClob(final int parameterIndex, final Clob x) throws
SQLException {
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -1379,7 +1374,7 @@ public class MonetPreparedStatement
@Override
public void setClob(final int parameterIndex, final Reader reader)
throws SQLException {
if (reader == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -1417,7 +1412,7 @@ public class MonetPreparedStatement
@Override
public void setClob(final int parameterIndex, final Reader reader,
final long length) throws SQLException {
if (reader == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
if (length < 0 || length > Integer.MAX_VALUE) {
@@ -1471,7 +1466,7 @@ public class MonetPreparedStatement
throws SQLException
{
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -1780,7 +1775,7 @@ public class MonetPreparedStatement
throws SQLException
{
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -2218,7 +2213,7 @@ public class MonetPreparedStatement
@Override
public void setString(final int parameterIndex, final String x) throws
SQLException {
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -2530,7 +2525,7 @@ public class MonetPreparedStatement
throws SQLException
{
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -2600,7 +2595,7 @@ public class MonetPreparedStatement
throws SQLException
{
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -2674,7 +2669,7 @@ public class MonetPreparedStatement
@Override
public void setURL(final int parameterIndex, final URL x) throws
SQLException {
if (x == null) {
- setNull(parameterIndex, -1);
+ setValue(parameterIndex, "NULL");
return;
}
@@ -2725,14 +2720,15 @@ public class MonetPreparedStatement
*/
@Override
public String toString() {
- final StringBuilder sb = new StringBuilder(256);
+ final StringBuilder sb = new StringBuilder(128 + paramCount *
64);
sb.append("Prepared SQL: ").append(sqlStatement).append("\n");
int param = 1;
for (int i = 0; i < size; i++) {
/* when column[i] == null it is a parameter, when
column[i] != null it is a result column of the prepared query */
if (column[i] == null) {
- sb.append(" parameter
").append(param++).append(" ").append(monetdbType[i]);
- sb.append(", set value: ").append((values[i] !=
null) ? values[i] : "<null>").append("\n");
+ sb.append(" parameter ").append(param).append("
").append(monetdbType[i]);
+ sb.append(", set value:
").append((paramValues[param] != null) ? paramValues[param] :
"<null>").append("\n");
+ param++;
}
}
return sb.toString();
@@ -2788,37 +2784,41 @@ public class MonetPreparedStatement
* @throws SQLException if the given index is out of bounds
*/
private final void setValue(final int parameterIndex, final String val)
throws SQLException {
- values[getParamIdx(parameterIndex)] = (val == null ? "NULL" :
val);
+ if (parameterIndex < 1 || parameterIndex > paramCount)
+ throw new SQLException("No such parameter with index: "
+ parameterIndex, "M1M05");
+
+ if (val != null)
+ paramValues[parameterIndex] = val;
+ else
+ paramValues[parameterIndex] = "NULL";
}
/**
- * Transforms the prepare query into a simple SQL query by replacing
- * the ?'s with the given column contents.
- * Mind that the JDBC specs allow `reuse' of a value for a column over
- * multiple executes.
+ * Constructs an "exec ##(paramval, ...)" statement string for the
current parameter values.
+ * Mind that the JDBC specs allow 'reuse' of a value for a parameter
over multiple executes.
*
- * @return the simple SQL string for the prepare query
- * @throws SQLException if not all columns are set
+ * @return the "exec ##(...)" string
+ * @throws SQLException if not all parameters are set with a value
*/
+ private StringBuilder execStmt; // created once, re-used multiple times
so much less objects are created and gc-ed
private final String transform() throws SQLException {
- final StringBuilder buf = new StringBuilder(8 + 12 * size);
- buf.append("exec ").append(id).append('(');
- // check if all columns are set and do a replace
- int col = 0;
- for (int i = 0; i < size; i++) {
- if (column[i] != null)
- continue;
- col++;
- if (col > 1)
- buf.append(',');
- if (values[i] == null)
- throw new SQLException("Cannot execute,
parameter " + col + " is missing.", "M1M05");
+ if (execStmt == null)
+ // first time use, create it once
+ execStmt = new StringBuilder(32 + paramCount * 32);
+ else
+ execStmt.setLength(0); // clear the buffer
- buf.append(values[i]);
+ execStmt.append("exec ").append(id).append('(');
+ // check if all parameters are set and add the parameter values
+ for (int param = 1; param <= paramCount; param++) {
+ if (paramValues[param] == null)
+ throw new SQLException("Cannot execute,
parameter " + param + " is missing.", "M1M05");
+ if (param > 1)
+ execStmt.append(',');
+ execStmt.append(paramValues[param]);
}
- buf.append(')');
-
- return buf.toString();
+ execStmt.append(')');
+ return execStmt.toString();
}
/**
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