Hi paul
Question 2, I agreed with you.
Or the comment means: "since flush do not promise data has been written, so we
need sync here to promise it..."
Overall it do sync rather than flush here.
在 12/12/2016 15:56, Paul Guo 写道:
1) In MirroredAppendOnly_FlushAndClose()
{
int ret;
errno = 0;
ret = FileSync(open->primaryFile);
if (ret != 0)
*primaryError = errno;
}
FileClose(open->primaryFile);
If I understand the code correctly, MirroredAppendOnly_DoOpen() sets
O_SYNC in file flags which leads to a hsync in FileClose(). So it looks
that FileSync() is not needed here to protect the data integrity.
2)
/*
* flush hdfs file
*
* NB: hdfs flush do NOT promise that data has been written on disk
* after flush, data can be read by others
*/
int
HdfsFileSync(File file)
It seems that HdfsFileSync finally does hsync finally, so I assume this
comment is wrong, right?
