You can design your own index, as you consideration for the pourpose. I'll try it
--- In firebird-support@yahoogroups.com, fabianoaspro@... wrote: > > This index uk_... Is the descending one? > Give-me the ddl of this index. > Em 16/04/2013 13:06, "skander_sp" <skander_sp@...> escreveu: > > > ** > > > > > > the plan is PLAN (O INDEX (UK_ORDENES_PRODUCCION_N_ORDEN)) > > and the readed rows it depend of the year... > > really i love to minimize the read for the last one year (the most used) > > but the only year read only a row is other with the higher N_Orden, all the > > rest read between some dozens and several hundreds. > > > > --- In firebird-support@yahoogroups.com, fabianoaspro@ wrote: > > > > > > Put here the new ddls then the sql you use and the plan used. > > > How many records it reads to get the new key? > > > Em 16/04/2013 12:01, "skander_sp" <skander_sp@> escreveu: > > > > > > > ** > > > > > > > > > > > > well, im not doing tryes in SP but in direct query, and i get different > > > > result, but not an optimistic one... > > > > > > > > Respect to the "compile or not" , my tests say to me it's enought to > > > > disconnect and reconnect again with the front as IBExpert (or exit and > > run > > > > the program). It's true, if don't do this, some time even not see the > > > > changes in some SP or TRIGGERS > > > > > > > > --- In firebird-support@yahoogroups.com, fabianoaspro@ wrote: > > > > > > > > > > Maybe I'm wrong but in my tests you need to recompile or do a full > > > > > backup/restore cycle. > > > > > Be sure you create the index Decending and that you put desc on both > > > > > statements when using the sql - like the another friend posted. > > > > > Em 16/04/2013 11:32, "skander_sp" <skander_sp@> escreveu: > > > > > > > > > > > ** > > > > > > > > > > > > > > > > > > Since when is necesary to recompile? > > > > > > Plans are not stored in the SP, the are calculated first time you > > use, > > > > > > after a connection > > > > > > > > > > > > May be necessary to disconnect and reconnect, but i doubt i need to > > > > > > recompile all my procedures to use new index. > > > > > > > > > > > > At least I read this ages ago, about the core of firebird. > > > > > > Or it's not? > > > > > > > > > > > > --- In firebird-support@yahoogroups.com, fabianoaspro@ wrote: > > > > > > > > > > > > > > If you use this code inside a SP you must recompile it for using > > > > this new > > > > > > > index. > > > > > > > Also is a good task to recompute the selectivity of the others > > > > indexes. > > > > > > > Sorry my bad english. > > > > > > > Em 16/04/2013 10:40, "skander_sp" <skander_sp@> escreveu: > > > > > > > > > > > > > > > ** > > > > > > > > > > > > > > > > > > > > > > > > Tks! > > > > > > > > This is a good solution... (and my first try) > > > > > > > > But don't work, still read the whole table for the yearorden > > given. > > > > > > > > > > > > > > > > I found a couple of "unoptimized" black-point in my > > application. > > > > > > > > And what it looks to be nice and wick became an pain in the > > ass. > > > > > > > > > > > > > > > > --- In firebird-support@yahoogroups.com, fabianoaspro@ wrote: > > > > > > > > > > > > > > > > > > Create a descending index with yearorden and norden in this > > > > sequence. > > > > > > > > Thats > > > > > > > > > it. > > > > > > > > > Em 16/04/2013 04:57, "skander_sp" <skander_sp@> escreveu: > > > > > > > > > > > > > > > > > > > ** > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Easy (and usual case) > > > > > > > > > > > > > > > > > > > > Simple table > > > > > > > > > > > > > > > > > > > > CREATE TABLE ORDENES ( > > > > > > > > > > ID_ORDEN INTEGER NOT NULL /* Primary key - GenId */ > > > > > > > > > > YEAR_ORDEN INTEGER NOT NULL /* Year of Orden */, > > > > > > > > > > N_ORDEN INTEGER NOT NULL /* Order in the Year */, > > > > > > > > > > ... /* no matter */ > > > > > > > > > > ); > > > > > > > > > > > > > > > > > > > > ALTER TABLE ORDENES ADD CONSTRAINT UK_ORDENES UNIQUE > > > > (YEAR_ORDEN, > > > > > > > > > > N_ORDEN)USING DESCENDING INDEX UK_ORDENES_YEAR_N_ORDEN; > > > > > > > > > > > > > > > > > > > > Now I need to access in the insert trigger, for next order > > to > > > > be > > > > > > > > assigned > > > > > > > > > > to N_ORDEN in the YEAR_ORDEN using > > > > > > > > > > > > > > > > > > > > select coalesce(max(o.n_orden),0)+1 > > > > > > > > > > from ordenes o > > > > > > > > > > where o.year_orden=new.year_orden > > > > > > > > > > into new.n_orden > > > > > > > > > > > > > > > > > > > > IT WORK!!!! nice, BUT NOT OPTIMIZED, in the Performance > > > > Analisys it > > > > > > > > read > > > > > > > > > > (indexed) all the N_ORDEN in the table, not going to the > > first > > > > > > (given > > > > > > > > the > > > > > > > > > > descending order of the index) > > > > > > > > > > > > > > > > > > > > How can optimize the index/query? > > > > > > > > > > Or simply is not possible doing more? > > > > > > > > > > > > > > > > > > > > Tks in advance > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > [Non-text portions of this message have been removed] >
