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. Matt ----- Original Message ----- From: <[EMAIL PROTECTED]> Sent: Friday, February 20, 2004 7:24 PM Subject: RE: Improving seek/access times -- does RAID help? > Run everything off a ramdisk ;-) > > Ted Gifford > > -----Original Message----- > From: Matt W > Sent: Friday, February 20, 2004 5:21 PM > Subject: Improving seek/access times -- does RAID help? > > Hi all, > > Can anyone tell me whether or not some kind of RAID will improve the > seek/access times during lots of random reads from, say, MyISAM data files? > I *do not care* about improved [sequential] transfer rates; I want the > fastest possible random access. > > I'm thinking that RAID won't give an improvement in this case, because the > disks can't know where to read from until MySQL issues the seek calls. :-( > About the only thing I can think of that may help is if you're using > striping, there won't be as much data on each disk so the head would need > shorter seeks. > > If RAID doesn't help the situation, any other ideas if the sub-6ms access > times of the fastest 15K SCSI drives isn't fast enough? :-) > > > Thanks, > > Matt -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
