Hi. I think if there are not some concurrency visitors, you should not use it. Otherwise, just put it. David Yeung, In China, Beijing. My First Blog:http://yueliangdao0608.cublog.cn My Second Blog:http://yueliangdao0608.blog.51cto.com My Msn: yueliangdao0...@gmail.com
2010/12/1 Wagner Bianchi <wagnerbianch...@gmail.com> > I'll provide it to, bear with me, pls... > > Best regards. > -- > WB > > > 2010/11/30 Johan De Meersman <vegiv...@tuxera.be> > > > Interesting, but I feel the difference is rather small - could you rerun > > with, say, 50.000 queries ? Also, different concurrency levels (1, 100) > > might be interesting to see. > > > > Yes, I'm to lazy to do it myself, what did you think :-p > > > > > > On Tue, Nov 30, 2010 at 4:01 PM, Wagner Bianchi < > wagnerbianch...@gmail.com > > > wrote: > > > >> Friends, I did a benchmark regarding to this subject. > >> Please, I am considering your comments. > >> => http://wbianchi.wordpress.com/2010/11/30/insert-x-insert-delayed/ > >> > >> Best regards. > >> -- > >> WB > >> > >> > >> 2010/11/30 Wagner Bianchi <wagnerbianch...@gmail.com> > >> > >> Maybe, the table in use must be a table that is inside cache now - SHOW > >>> OPEN TABLES, controlled by table_cache, I mean. > >>> > >>> Well, if the amount of data trasactioned is too small as a simple > INSERT, > >>> you don't have to be worried, I suggest. If you partition the table, we > must > >>> a benchmark to know the performance relation of a INSERT and compress > data > >>> into Archive Storage Engine or the insertion data into a partitioned > table. > >>> > >>> Best regards. > >>> -- > >>> WB > >>> > >>> > >>> 2010/11/30 Johan De Meersman <vegiv...@tuxera.be> > >>> > >>> I would assume that it's slower because it gets put on the delay thread > >>>> anyway, and thus executes only whenever that thread gets some > attention. I'm > >>>> not sure wether there are other influencing factors. > >>>> > >>>> I should also think that "not in use" in this context means "not > locked > >>>> against inserts", so the MyISAM insert-while-selecting at the end of a > >>>> continguous table may well apply. > >>>> > >>>> No guarantees, though - I'm not that hot on this depth. > >>>> > >>>> > >>>> > >>>> On Tue, Nov 30, 2010 at 8:46 AM, WLGades <wlga...@gmail.com> wrote: > >>>> > >>>>> What I'm confused by though, is this line. > >>>>> > >>>>> "Note that INSERT DELAYED is slower than a normal INSERT if the table > >>>>> is not > >>>>> otherwise in use." What's the definition of "in use"? Does a > logging > >>>>> table > >>>>> do that given that it's pretty much append-only/write-only? > >>>>> > >>>>> Waynn > >>>>> > >>>>> On Mon, Nov 29, 2010 at 10:19 PM, Johan De Meersman < > >>>>> vegiv...@tuxera.be>wrote: > >>>>> > >>>>> > No, I think it's a good idea to do INSERT DELAYED here - it's only > >>>>> logging > >>>>> > application, and it's generally more important to not slow down the > >>>>> > application for that. It's only ever into a single table, so > there's > >>>>> only > >>>>> > going to be a single delay thread for it anyway. > >>>>> > > >>>>> > Archive tables are a good idea, agreed, but I suspect that inserts > >>>>> into > >>>>> > that are going to be slower than into regular MyISAM because of the > >>>>> > compression, so why not use that overhead to (slightly) speed up > your > >>>>> > end-user experience instead ? > >>>>> > > >>>>> > You can always partition the table based on the log date or > whatever, > >>>>> if > >>>>> > your table risks getting too big. > >>>>> > > >>>>> > > >>>>> > > >>>>> > On Tue, Nov 30, 2010 at 1:03 AM, Wagner Bianchi < > >>>>> wagnerbianch...@gmail.com > >>>>> > > wrote: > >>>>> > > >>>>> >> Well, analyze if you need to create an excessive overhead into > the > >>>>> MySQL > >>>>> >> Server because a simple INSERT. What you must have a look is it: > >>>>> >> > >>>>> >> - How much data this connection is delivering to MySQL's > handlers? > >>>>> >> - A word DELAYED in this case is making MySQL surfer? > >>>>> >> > >>>>> >> Perhaps, you are sophisticating something that do not need it. > >>>>> Besides it, > >>>>> >> analyzing your "log table", I imagine this table can be an Archive > >>>>> table > >>>>> >> instead of MyISAM. Log tables or history tables can be controlled > by > >>>>> >> Archive > >>>>> >> Storage Engine to have more compressed data. Although, Archive > >>>>> Storage > >>>>> >> Engine only supports SELECT and INSERT. Maybe, a good deal to you, > >>>>> get rid > >>>>> >> of you INSERT DELAYED: > >>>>> >> > >>>>> >> > >>>>> >> - ALTER TABLE <tbl_name> ENGINE = ARCHIVE; > >>>>> >> > >>>>> >> > >>>>> >> Best regards. > >>>>> >> -- > >>>>> >> WB > >>>>> >> > >>>>> >> > >>>>> >> 2010/11/29 WLGades <wlga...@gmail.com> > >>>>> >> > >>>>> >> > I'm adding a table to our site that logs all page loads. In the > >>>>> past, > >>>>> >> when > >>>>> >> > I built this, I used MyISAM and INSERT DELAYED. I went back to > >>>>> look at > >>>>> >> the > >>>>> >> > documentation to see if I should still do this, and saw this > >>>>> (taken from > >>>>> >> > http://dev.mysql.com/doc/refman/5.1/en/insert-delayed.html): > >>>>> >> > > >>>>> >> > Note that INSERT DELAYED is slower than a normal INSERT if the > >>>>> table is > >>>>> >> not > >>>>> >> > otherwise in use. There is also the additional overhead for the > >>>>> server > >>>>> >> to > >>>>> >> > handle a separate thread for each table for which there are > >>>>> delayed > >>>>> >> rows. > >>>>> >> > This means that you should use INSERT DELAYED only when you are > >>>>> really > >>>>> >> sure > >>>>> >> > that you need it. > >>>>> >> > > >>>>> >> > Does that mean that I shouldn't use it if all I'm doing is > INSERT > >>>>> >> > (essentially an append-only table), with only very occasional > >>>>> SELECTs? > >>>>> >> In > >>>>> >> > addition, the last time I took this approach for logging, it > >>>>> worked well > >>>>> >> > until the table got to 65M+ rows, when it would crash every now > >>>>> and > >>>>> >> then. > >>>>> >> > I > >>>>> >> > know I can archive off the table on a per month/quarter basis as > >>>>> well. > >>>>> >> > > >>>>> >> > Waynn > >>>>> >> > > >>>>> >> > >>>>> > > >>>>> > > >>>>> > > >>>>> > -- > >>>>> > Bier met grenadyn > >>>>> > Is als mosterd by den wyn > >>>>> > Sy die't drinkt, is eene kwezel > >>>>> > Hy die't drinkt, is ras een ezel > >>>>> > > >>>>> > >>>> > >>>> > >>>> > >>>> -- > >>>> Bier met grenadyn > >>>> Is als mosterd by den wyn > >>>> Sy die't drinkt, is eene kwezel > >>>> Hy die't drinkt, is ras een ezel > >>>> > >>> > >>> > >> > > > > > > -- > > Bier met grenadyn > > Is als mosterd by den wyn > > Sy die't drinkt, is eene kwezel > > Hy die't drinkt, is ras een ezel > > >
