sencha extjs store hasmany iteration is slow - extjs

Question

I have a serious performance problem updating records through a hasMany relation. (using sencha extjs 4.0)
Suppose we have a model with a hasMany relation. I'll rewrite my actual stuff in a simplified model based on sports teams and their players.
Ext.define('project.model.Team', {
extend: 'Ext.data.Model'
, fields: [
{name: 'id', type: 'int'}
, {name: 'name', type: 'string'}
]
, hasMany: [
{ model: 'project.model.Player', name: 'players' }
]
});
Ext.define('project.model.Player', {
extend: 'Ext.data.Model'
, fields: [
{name: 'id', type: 'int'}
, {name: 'team_id', type: 'int'}
, {name: 'name', type: 'string'}
, {name: 'attribute', type: 'int'}
]
, associations: [
{ type: 'belongsTo', model: 'project.model.Team', foreignKey: 'team_id', primaryKey: 'id' }
]
});
Suppose there are a lot of teams and a lot of players, but we want to update something on each player in a specific team. Maybe the team played a game, so we add one game played. Details not important.
This was the working code. It wasn't a problem until someone had a "team" with a lot of "players" in an already pretty large database. This loop takes forever at a fairly modest size. I think set is triggering extra checks on every iteration, instead of just setDirty.
teamStore.getById(record.get('item_id')).players().each(function(player) {
var player_instance = exceptionStore.getById(exception.get('id'));
player_instance.set('attribute', value);
});
playerStore.sync();
This runs really quickly, sets the attribute on the reference object, and does NOTHING.
teamStore.getById(record.get('item_id')).players().each(function(player) {
player.set('attribute', value);
});
teamStore.sync();
playerStore.sync();
I think that code doesn't work because the players are just some sort of reference with no info other than their id in the player store, but they are not actually connected to the store in any way.
Is there some faster way to get the players associated with a team, and actually do something?

Answer 1

You need to put the store in batch update mode with suspendEvents, so it queues up all the changes, rather than try to do all the internal bookkeeping one-at-a-time during your loop. Once you are done changing it, let it catch up in resumeEvents.
https://docs.sencha.com/extjs/4.0.7/#!/api/Ext.data.Store-method-suspendEvents
playerStore.suspendEvents();
playerStore.query('team_id', team_id).each(function(player){
player.set('attribute', value);
});
playerStore.resumeEvents();
playerStore.sync();