Comment 1 for bug 899931
Revision history for this message
| Stewart Smith (stewart) wrote Re: [Bug 899931] [NEW] tar4ibd reads files inefficiently | #1 |
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73416ba
(Get the code!)
On Sun, 04 Dec 2011 14:53:09 -0000, Alexey Kopytov <email address hidden> wrote:
> Public bug reported:
>
> tar4ibd is using very inefficient way to read files. To support
> compressed tables, it starts with a 1KB block size and calls read() with
> that size. If page verification fails, it increases the block size,
> calls lseek() to restore the original position and retries read().
>
> It can be optimized in two ways (basically, by doing what xtrabackup
> binary does):
>
> - read in large chunks, and then process them with different page sizes if necessary;
> - don't consider small block sizes and default to 16KB when zip_size == 0, when the data file is not compressed.
>
> I'm not sure it makes sense to fix this in 1.6, as tar4ibd is hopefully
> going away in 1.7. But reporting it just for the record.
maybe posix_fadvise(
--
Stewart Smith