StatementCache

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org.apache.derby.diag
Class StatementCache

java.lang.Object
  org.apache.derby.vti.VTITemplate
      org.apache.derby.diag.StatementCache

All Implemented Interfaces:: java.sql.ResultSet

public final class StatementCache
extends org.apache.derby.vti.VTITemplate

StatementCache is a virtual table that shows the contents of the SQL statement cache. This virtual table can be invoked by calling it directly.

 select * from new org.apache.derby.diag.StatementCache() t

The StatementCache virtual table has the following columns:

ID CHAR(36) - not nullable. Internal identifier of the compiled statement.
SCHEMANAME VARCHAR(128) - nullable. Schema the statement was compiled in.
SQL_TEXT VARCHAR(32672) - not nullable. Text of the statement
UNICODE BIT/BOOLEAN - not nullable. True if the statement is compiled as a pure unicode string, false if it handled unicode escapes.
VALID BIT/BOOLEAN - not nullable. True if the statement is currently valid, false otherwise
COMPILED_AT TIMESTAMP nullable - time statement was compiled, requires STATISTICS TIMING to be enabled.

The internal identifier of a cached statement matches the toString() method of a PreparedStatement object for a Cloudscape database.

This class also provides a static method to empty the statement cache, StatementCache.emptyCache()

Field Summary

private static org.apache.derby.iapi.sql.ResultColumnDescriptor[] columnInfo


private org.apache.derby.impl.sql.GenericPreparedStatement currentPs


private java.util.Vector data


private static java.sql.ResultSetMetaData metadata


private int position


private boolean wasNull


Fields inherited from interface java.sql.ResultSet

CLOSE_CURSORS_AT_COMMIT, CONCUR_READ_ONLY, CONCUR_UPDATABLE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, HOLD_CURSORS_OVER_COMMIT, TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE, TYPE_SCROLL_SENSITIVE

Constructor Summary

StatementCache()


Method Summary

void close()
          This method closes the result set and frees any associated resources.

static void emptyCache()
          Empty the statement cache.

boolean getBoolean(int colId)
          This method returns the value of the specified column as a Java boolean.

java.sql.ResultSetMetaData getMetaData()
          This method returns data about the columns returned as part of the result set as a ResultSetMetaData instance.

java.lang.String getString(int colId)
          This method returns the value of the specified column as a Java String.

java.sql.Timestamp getTimestamp(int colId)
          This method returns the value of the specified column as a Java java.sql.Timestamp.

boolean next()
          This method advances to the next row in the result set.

boolean wasNull()
          This method tests whether the value of the last column that was fetched was actually a SQL NULL value.

Methods inherited from class org.apache.derby.vti.VTITemplate

absolute, afterLast, beforeFirst, cancelRowUpdates, clearWarnings, deleteRow, findColumn, first, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getConcurrency, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getInt, getInt, getLong, getLong, getObject, getObject, getObject, getObject, getRef, getRef, getRow, getShort, getShort, getStatement, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, insertRow, isAfterLast, isBeforeFirst, isFirst, isLast, last, moveToCurrentRow, moveToInsertRow, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setFetchDirection, setFetchSize, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateRow, updateShort, updateShort, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

position

private int position

data

private java.util.Vector data

currentPs

private org.apache.derby.impl.sql.GenericPreparedStatement currentPs

wasNull

private boolean wasNull

columnInfo

private static final org.apache.derby.iapi.sql.ResultColumnDescriptor[] columnInfo

metadata

private static final java.sql.ResultSetMetaData metadata

Constructor Detail

StatementCache

public StatementCache()
               throws java.sql.SQLException

Method Detail

emptyCache

public static void emptyCache()
                       throws java.sql.SQLException

Empty the statement cache. Must be called from a SQL statement, e.g.

                CALL org.apache.derby.diag.StatementCache::emptyCache()

public boolean next()