Issue 4134: Fixing memory leak error when using DirectEntryLogger

[graysonzeng]

Descriptions of the changes in this PR:

Motivation

When we use DirectIO and a catch up read occurs, a memory leak occurs because the ByteBuf is not released.

Because although in the internalReadEntry method in DirectEntryLogger, even if the upper layer fillReadAheadCache uses the ReferenceCountUtil.release(entry) method in the finally block to release ByteBuf, it will still cause an exception thrown by internalReadEntry, and the entryLogger.readEntry method happens to be in try. ..catch unexpected, causing ByteBuf to not be released correctly

Changes

Master Issue: #4134

[graysonzeng]

After this repairing and observing for a day, the OOM problem no longer occurs in the direct memory.

[horizonzy]

I have a question about this change.

The issue is fixed by line_255, right? That means the entry logger file already be dirty.

If the code reaches line_266, the buf should be null.

[graysonzeng]

I have a question about this change.

The issue is fixed by line_255, right? That means the entry logger file already be dirty.

If the code reaches line_266, the buf should be null.

Yes it has been fixed by line_255, should I remove line_266?

[horizonzy]

I have a question about this change.
The issue is fixed by line_255, right? That means the entry logger file already be dirty.
If the code reaches line_266, the buf should be null.

Yes it has been fixed by line_255, should I remove line_266?

I think it can be removed.

[graysonzeng]

I have a question about this change.
The issue is fixed by line_255, right? That means the entry logger file already be dirty.
If the code reaches line_266, the buf should be null.

Yes it has been fixed by line_255, should I remove line_266?

I think it can be removed.

line_266 has been removed, thanks~

[horizonzy]

As I said, although this PR could fix the memory leak, the entry log file already be dirty, it can't read data correctly.

There is an issue with the entry log file about dirty. #4040

[eolivelli]

Great catch !

[hangc0276]

We don't need to move the ByteBuf out of the try-catch code block.

[graysonzeng]

We don't need to move the ByteBuf out of the try-catch code block.

Fixed it