mysql - Grails addTo* slowly performance with event -

in grails app i'm using technologies excited i'm having problems performance, describe cenario:

• one table 4m+ entires;
• i'm using event bus api;
• grails 2.2.3;
• mysql db;

when client create new room, alloc created too.

pseudo-code:     room {       hasmany = aloccs: alloc     } 

look code (is not real code, same equality):

@listener(topic="topicaloccreator") def aloccreator(eventmessage<long> message) {      localdate start = new datetime().tolocaldate()     localdate end = new datetime().plusyears(2).plusmonths(6).tolocaldate()     localdate tmp = start       room room = room.get(message.data)     list channels = channel.list     while(tmp.compareto(end) <= 0) {         for(channel in channels) {             room.addtoalocs(new aloc(0, 0, tmp.todate(), channel))         }         tmp = tmp.plusdays(1)     }      //end of method } 

this codes works fine, generated lot of alloc objects , put in hibernate session.

what it's correct way job, using flush? batch? - call method assync.

this codes work fine until (07/14) during days slow, 1.30 min insert 10k of alloc in database;

thanks lot suggestions.

because allocs set (default grails collection type when define hasmany relationship), grails has load whole collection memory before insert can happen in order guarantee uniqueness.

take @ bert beckwith's presentation on performance implications of using gorm collections.

i think have couple of options. dispense collection reference entirely, , define classes this:

class alloc {     room room }  class room {     //no reference child allocs } 

alternatively, define allocs collection bag:

class alloc {     static belongsto = [room: room] }  class room {     collection allocs     static hasmany = [allocs: alloc] } 

in case there's no need uniqueness check , addto... method won't need load every alloc instance memory. will, however, responsible maintaining uniqueness yourself...

reference