Matt W wrote:
> Hi Ted,
> Heh. :-) This could be many GBs. There's no problem reading rows that
> are in RAM (cached by the OS) -- can read over 10,000/second. If
> there's enough RAM, the OS will take care of it (you could cat table.MYD
> to /dev/null). No ramdisk necessary. :-)
> BTW, this is for MySQL's full-text search. It works pretty well (fast)
> as far as doing the lookups and searching in the index. That's not a
> concern at all. The problem is that it *has to* read the data file for
> each matching row (and possibly non-matching rows, depending on the
> search). :-( Searches need to be reasonably fast on millions of rows,
> while possibly reading 10s of thousands of data rows. It takes a lot
> more time when those rows aren't cached.
> The only thing I've thought of so far is symlinking the data file on a
> separate drive, but I'm not sure how much that will actually help.
Post your schema (use SHOW CREATE TABLE), and give an example of a couple of
queries that are slow including the output of EXPLAIN. It is quite possible that
we can find a fairly simple solution to avoid excessive random disk access.
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