bzr commit into mysql-6.0-falcon-team branch (kevin.lewis:2722) Bug#36631

[Kevin Lewis]

#At file:///C:/Work/bzr/Merge/mysql-6.0-falcon-team/ based on
revid:john.embretsen@stripped

 2722 Kevin Lewis	2009-06-10
      Bug#36631 - Make sure that SerialLogControl::currentLength is always set correctly. 
If it is too short and a buffer needs to be re-read, not enough of the serial log will be
read back inot the buffer. When it gets to the end of the current length and calls
SerialLogControl::nextRecord() it will hit an assert when it reads the previous contents
of that buffer, which is now junk.  The problem is that the block length indicates a
larger window than the currentLength.  
      
      SerialLogControl::currentLength is now updated in each location that the current
writePtr is extended.  This is three more places than before.
      
      In addition, some comments and some just-in-case code is added to
SRLUpdateRecords::thaw().  Since this thaw is not calling setWindow(), but only doing a
subset of that function, the task of clearing anddeactivating the old inputWindow that is
done in setWindow() is repeated here.

    modified:
      storage/falcon/SRLUpdateRecords.cpp
      storage/falcon/SerialLog.cpp
=== modified file 'storage/falcon/SRLUpdateRecords.cpp'
--- a/storage/falcon/SRLUpdateRecords.cpp	2009-06-03 18:15:32 +0000
+++ b/storage/falcon/SRLUpdateRecords.cpp	2009-06-10 07:36:02 +0000
@@ -73,7 +73,7 @@ char* SRLUpdateRecords::thaw(RecordVersi
 	// activate the window, reading from disk if necessary
 
 	SerialLogWindow *window = log->findWindowGivenOffset(record->getVirtualOffset());
-	
+
 	// If the serial log window is no longer available, then this virtualOffset is 
 	// no longer any good.  Reset it and return.
 
@@ -85,9 +85,20 @@ char* SRLUpdateRecords::thaw(RecordVersi
 	Sync sync(&log->syncWrite, "SRLUpdateRecords::thaw");
 	sync.lock(Exclusive);
 
-	// Return pointer to record data
+	// Instead of calling setWindow(), we only set input and inputEnd.
+	// Do not even assign our local 'window' to inputWindow because we will
+	// deactivate it here.
+
+	if (control->inputWindow && control->inputWindow != window)
+		{
+		control->inputWindow->deactivateWindow();
+		control->inputWindow = NULL;
+		}
+
+	// Set the input and inputEnd pointers to the record we are thawing.
 
-	control->input = window->buffer + (record->getVirtualOffset() -
window->virtualOffset);
+	uint64 recordOffset = record->getVirtualOffset() - window->virtualOffset;
+	control->input = window->buffer + recordOffset;
 	control->inputEnd = window->bufferEnd;
 
 	// Get section id, record id and data length written. Input pointer will be at

=== modified file 'storage/falcon/SerialLog.cpp'
--- a/storage/falcon/SerialLog.cpp	2009-05-12 14:35:40 +0000
+++ b/storage/falcon/SerialLog.cpp	2009-06-10 07:36:02 +0000
@@ -373,7 +373,7 @@ void SerialLog::recover()
 	// probing the log files, open a window on the first block
 	// we're going to use for recovery.  That should work, but
 	// if it doesn't, complain.
-    
+
 	lastWindow->deactivateWindow();
 	SerialLogWindow *window = findWindowGivenBlock(readBlockNumber);
 	
@@ -544,6 +544,8 @@ void SerialLog::overflowFlush(void)
 	// OK, we're going to do some writing.  Start by locking the serial log
 
 	*writePtr++ = srlEnd | LOW_BYTE_FLAG;
+	if (writePtr > writeWindow->buffer + writeWindow->currentLength)
+		writeWindow->currentLength = (int) (writePtr - writeWindow->buffer);
 	writeBlock->length = (int) (writePtr - (UCHAR*) writeBlock);
 	writeWindow->setLastBlock(writeBlock);
 	lastReadBlock = writeBlock->readBlockNumber = getReadBlock();
@@ -638,6 +640,8 @@ uint64 SerialLog::flush(bool forceNewWin
 	ASSERT(writer == NULL || writer == thread);
 	writer = thread;
 	*writePtr++ = srlEnd | LOW_BYTE_FLAG;
+	if (writePtr > writeWindow->buffer + writeWindow->currentLength)
+		writeWindow->currentLength = (int) (writePtr - writeWindow->buffer);
 	writeBlock->length = (int) (writePtr - (UCHAR*) writeBlock);
 	lastReadBlock = writeBlock->readBlockNumber = getReadBlock();
 
@@ -795,6 +799,8 @@ void SerialLog::putData(uint32 length, c
 	UCHAR recordCode = *recordStart;
 	writeBlock->length = (int) (recordStart - (UCHAR*) writeBlock);
 	writePtr = recordStart;
+	if (writePtr > writeWindow->buffer + writeWindow->currentLength)
+		writeWindow->currentLength = (int) (writePtr - writeWindow->buffer);
 	overflowFlush();
 
 	while (writePtr + length + tailLength >= writeWarningTrack)


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