• Bruce Momjian's avatar
    > If read or write fails. Position will left the same. This · a194574d
    Bruce Momjian authored
    > situation is already tracked in File routines, but a little bit
    > incorrectly.
    
    > After small survey in Linux kernel code, I am not sure about
    > it.  New patch set pos to unknown in the case of read/write
    > fails. And do lseek again.
    
    > Here is the full patch for this. This patch reduce amount of
    > lseek call ten ti mes for update statement and twenty times for
    > select statement. I tested joined up date and count(*) select
    > for table with rows > 170000 and 10 indices.  I think this is
    > worse of trying. Before lseek calls account for more than 5% o
    > f time.  Now they are 0.89 and 0.15 respectevly.
    >
    > Due to only one file modification patch should be applied in
    > src/backedn/stora ge/file/ dir.
    
    -- Sincerely Yours,
    Denis Perchine
    a194574d
fd.c 27.6 KB