ErrorLogReader (Apache Derby V10.14 Internals)

java.lang.Object
- org.apache.derby.vti.VTITemplate
- - org.apache.derby.diag.ErrorLogReader

All Implemented Interfaces:

java.lang.AutoCloseable, java.sql.ResultSet, java.sql.Wrapper, AwareVTI
```
public class ErrorLogReader
extends VTITemplate
```
ErrorLogReader is a virtual table interface (VTI) which contains all the statements of "interest" in db2j.log or a specified file when db2j.language.logStatementText=true.
One use of this VTI is to determine the active transactions and the SQL statements in those transactions at a given point in time, say when a deadlock or lock timeout occurred. In order to do that, you must first find the timestamp (timestampConstant) of interest in the error log. The SQL to view the active transactions at a given in time is:
```
SELECT vti.ts, threadid, cast(xid as int) as xid_int, cast(lccid as int) as lccid_int, logtext 
                 FROM new org.apache.derby.diag.ErrorLogReader() vti, 
                        (VALUES timestampConstant) t(ts)
                 WHERE vti.ts <= t.ts AND 
                                vti.ts >
                                        (SELECT MAX(ts) IS NULL ? '2000-01-01 00:00:00.1' : MAX(ts)
                                         FROM new org.apache.derby.diag.ErrorLogReader() vti_i
                                         WHERE (logtext LIKE 'Committing%' OR
                                                        logtext LIKE 'Rolling%') AND
                                                   vti.xid = vti_i.xid AND ts < t.ts)
                 ORDER BY xid_int, vti.ts
        
```
The ErrorLogReader virtual table has the following columns:
- TS varchar(26) - the timestamp of the statement.
- THREADID varchar(40) - the thread name.
- XID varchar(15) - the transaction ID.
- LCCID varchar(15) - the connection ID.
- DATABASE varchar(128) - Database name
- DRDAID varchar(50) - nullable. DRDA ID for network server session.
- LOGTEXT long varchar - text of the statement or commit or rollback.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.derby.vti.VTITemplate
  VTITemplate.ColumnDescriptor

Field Summary

Fields
Modifier and Type	Field	Description
`private static java.lang.String`	`BEGIN_DATABASE_STRING`
`private static java.lang.String`	`BEGIN_DRDAID_STRING`
`private static java.lang.String`	`BEGIN_EXECUTING_STRING`
`private static java.lang.String`	`BEGIN_THREAD_STRING`
`private static java.lang.String`	`BEGIN_XID_STRING`
`private java.io.BufferedReader`	`bufferedReader`
`private static ResultColumnDescriptor[]`	`columnInfo`
`private int`	`databaseIndex`
`private int`	`drdaidIndex`
`private static java.lang.String`	`END_DATABASE_STRING`
`private static java.lang.String`	`END_DRDAID_STRING`
`private static java.lang.String`	`END_EXECUTING_STRING`
`private static java.lang.String`	`END_THREAD_STRING`
`private static java.lang.String`	`END_TIMESTAMP`
`private static java.lang.String`	`END_XID_STRING`
`private int`	`endTimestampIndex`
`private boolean`	`gotFile`
`private java.lang.String`	`inputFileName`
`private java.io.InputStreamReader`	`inputFileStreamReader`
`private java.io.InputStream`	`inputStream`
`private int`	`lccidIndex`
`private java.lang.String`	`line`
`private static java.sql.ResultSetMetaData`	`metadata`
`private static java.lang.String`	`PARAMETERS_STRING`
`private int`	`threadIndex`
`private int`	`xidIndex`

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

Constructors
Constructor	Description
`ErrorLogReader()`	ErrorLogReader() accesses the derby.log in derby.system.home, if set, otherwise it looks in the current directory.
`ErrorLogReader(java.lang.String inputFileName)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`
`java.sql.ResultSetMetaData`	`getMetaData()`
`java.lang.String`	`getString(int columnNumber)`	All columns in the Db2jLogReader VTI have a of String type.
`boolean`	`next()`
`boolean`	`wasNull()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.sql.ResultSet
updateObject, updateObject, updateObject, updateObject

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, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getConcurrency, getContext, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getHoldability, getInt, getInt, getLong, getLong, getNCharacterStream, getNCharacterStream, getNClob, getNClob, getNString, getNString, getObject, getObject, getObject, getObject, getObject, getObject, getRef, getRef, getReturnTableSignature, getRow, getRowId, getRowId, getShort, getShort, getSQLXML, getSQLXML, getStatement, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, insertRow, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, isWrapperFor, last, moveToCurrentRow, moveToInsertRow, notImplemented, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setContext, setFetchDirection, setFetchSize, unwrap, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateClob, updateClob, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNString, updateNString, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateRow, updateRowId, updateRowId, updateShort, updateShort, updateSQLXML, updateSQLXML, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp

- Field Detail
  - gotFile
```
private boolean gotFile
```
  - inputFileStreamReader
```
private java.io.InputStreamReader inputFileStreamReader
```
  - inputStream
```
private java.io.InputStream inputStream
```
  - bufferedReader
```
private java.io.BufferedReader bufferedReader
```
  - inputFileName
```
private java.lang.String inputFileName
```
  - line
```
private java.lang.String line
```
  - endTimestampIndex
```
private int endTimestampIndex
```
  - threadIndex
```
private int threadIndex
```
  - xidIndex
```
private int xidIndex
```
  - lccidIndex
```
private int lccidIndex
```
  - databaseIndex
```
private int databaseIndex
```
  - drdaidIndex
```
private int drdaidIndex
```
  - END_TIMESTAMP
```
private static final java.lang.String END_TIMESTAMP
```
    See Also:
    
    Constant Field Values
  - PARAMETERS_STRING
```
private static final java.lang.String PARAMETERS_STRING
```
    See Also:
    
    Constant Field Values
  - BEGIN_THREAD_STRING
```
private static final java.lang.String BEGIN_THREAD_STRING
```
    See Also:
    
    Constant Field Values
  - END_THREAD_STRING
```
private static final java.lang.String END_THREAD_STRING
```
    See Also:
    
    Constant Field Values
  - BEGIN_XID_STRING
```
private static final java.lang.String BEGIN_XID_STRING
```
    See Also:
    
    Constant Field Values
  - END_XID_STRING
```
private static final java.lang.String END_XID_STRING
```
    See Also:
    
    Constant Field Values
  - BEGIN_DATABASE_STRING
```
private static final java.lang.String BEGIN_DATABASE_STRING
```
    See Also:
    
    Constant Field Values
  - END_DATABASE_STRING
```
private static final java.lang.String END_DATABASE_STRING
```
    See Also:
    
    Constant Field Values
  - BEGIN_DRDAID_STRING
```
private static final java.lang.String BEGIN_DRDAID_STRING
```
    See Also:
    
    Constant Field Values
  - END_DRDAID_STRING
```
private static final java.lang.String END_DRDAID_STRING
```
    See Also:
    
    Constant Field Values
  - BEGIN_EXECUTING_STRING
```
private static final java.lang.String BEGIN_EXECUTING_STRING
```
    See Also:
    
    Constant Field Values
  - END_EXECUTING_STRING
```
private static final java.lang.String END_EXECUTING_STRING
```
    See Also:
    
    Constant Field Values
  - columnInfo
```
private static final ResultColumnDescriptor[] columnInfo
```
  - metadata
```
private static final java.sql.ResultSetMetaData metadata
```
- Constructor Detail
  - ErrorLogReader
```
public ErrorLogReader()
               throws StandardException
```
    ErrorLogReader() accesses the derby.log in derby.system.home, if set, otherwise it looks in the current directory. ErrorLogReader('filename') will access the specified file name.
    
    Throws:
    
    StandardException
  - ErrorLogReader
```
public ErrorLogReader(java.lang.String inputFileName)
               throws StandardException
```
    Throws:
    
    StandardException
- Method Detail
  - getMetaData
```
public java.sql.ResultSetMetaData getMetaData()
```
    Specified by:
    
    getMetaData in interface java.sql.ResultSet
    
    Overrides:
    
    getMetaData in class VTITemplate
    
    See Also:
    
    ResultSet.getMetaData()
  - next
```
public boolean next()
             throws java.sql.SQLException
```
    Throws:
    
    java.sql.SQLException - If database-access error occurs.
    
    See Also:
    
    ResultSet.next()
  - close
```
public void close()
```
    See Also:
    
    ResultSet.close()
  - getString
```
public java.lang.String getString(int columnNumber)
                           throws java.sql.SQLException
```
    All columns in the Db2jLogReader VTI have a of String type.
    
    Specified by:
    
    getString in interface java.sql.ResultSet
    
    Overrides:
    
    getString in class VTITemplate
    
    Throws:
    
    java.sql.SQLException - If database-access error occurs.
    
    See Also:
    
    ResultSet.getString(int)
  - wasNull
```
public boolean wasNull()
```
    Specified by:
    
    wasNull in interface java.sql.ResultSet
    
    Overrides:
    
    wasNull in class VTITemplate
    
    See Also:
    
    ResultSet.wasNull()

Class ErrorLogReader

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.derby.vti.VTITemplate

Field Summary

Fields inherited from interface java.sql.ResultSet

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.sql.ResultSet

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

Field Detail

gotFile

inputFileStreamReader

inputStream

bufferedReader

inputFileName

line

endTimestampIndex

threadIndex

xidIndex

lccidIndex

databaseIndex

drdaidIndex

END_TIMESTAMP

PARAMETERS_STRING

BEGIN_THREAD_STRING

END_THREAD_STRING

BEGIN_XID_STRING

END_XID_STRING

BEGIN_DATABASE_STRING

END_DATABASE_STRING

BEGIN_DRDAID_STRING

END_DRDAID_STRING

BEGIN_EXECUTING_STRING

END_EXECUTING_STRING

columnInfo

metadata

Constructor Detail

ErrorLogReader

ErrorLogReader

Method Detail

getMetaData

next

close

getString

wasNull