Re: Memory Management
Re: Memory Management
- Subject: Re: Memory Management
- From: Chuck Hill <email@hidden>
- Date: Fri, 6 Mar 2009 16:19:53 -0800
On Mar 4, 2009, at 6:30 PM, Jeff Schmitz wrote:
A little more info on my problem (yes I'm confused). For my
processing, all my data is not in one table. I need to work on one
coherent set of data at a time that is related across tables via
joins.
My tables are setup as follows:
Pool----*>>Entry-----63>>Game-----2>TeamPopup
To do my processing, specifically I need the rows
Tables? Rows? Joins? If you are thinking in SQL terms, one of two
things is probably true:
1. You should be doing this in SQL, not EOF
2. You are approaching it the wrong way
from the Entry table, the Game table and the TeamPopup table that
are associated with a single pool via joins from the pool's entries
to each entry's games to each game's teams.
To process 1 pool that has say 300 entries, each entry having 63
Games and each Game having 2 Teams, That's 63 rows from the Entry
table, 18900 distinct rows from the Games table and 37800 distinct
rows from the Teams table. My first question is, with a pool name in
hand, how do I fashion the qualifier so that all the Pool's
associated Game Rows and Team rows that I need for processing are
batch fetched in?
Have you turned on SQL logging to see what is getting sent to the
database?
Does your model have Batch Faulting configured for these relationships?
http://wiki.objectstyle.org/confluence/display/WO/EOF-Modeling-EOModeler#EOF-Modeling-EOModeler-BatchFaulting
Are you using prefetching keypaths with the fetch spec?
http://developer.apple.com/documentation/MacOSXServer/Reference/WO54_Reference/com/webobjects/eocontrol/EOFetchSpecification.html#setPrefetchingRelationshipKeyPaths(com.webobjects.foundation.NSArray)
Chuck
If it helps, I currently process the data something like this (yes,
my actual code is better structured, but this shows the inner
workings of what's really running).
Pool currPool = Pool.fetchStandardPoolWithName(ec, poolName);
ListIterator<Entry> entryIter = pool.entries().listIterator();
Entry nextEntry;
while (entryIter.hasNext()) {
nextEntry = entryIter.next();
for (int regionIndex = 0; regionIndex < 4; regionIndex ++) {
for (int gameIndex = 0; gameIndex < 15; j++) {
EOQualifier gameQual =
Game.GROUP.eq(regionIndex).and(Game.GAME.eq(gameIndex));
Game currentGame = nextEntry.games(gameQual).objectAtIndex(0);
EOQualifier selQual =
TeamPopup.COMBO_INDEX.eq(currentGame.selectedItem());
int seedOfSelectedTeam =
currentGame.teamPopups(selQual).lastObject().seed();
// Do stuff with the seed and retrieve other
information about the teams and games
}
}
}
So in the end, my first questions is regarding:
First, create a fetch specification for the main EO that you wish
to operate on and prep it for pulling out the primary key;
How do I create the fetch specification when I need to work on
multiple related EOs at the same time?
On Mar 1, 2009, at 10:04 PM, Andrew Lindesay wrote:
Hello Jeff;
Fair enough. I will keep it simple...
First, create a fetch specification for the main EO that you wish
to operate on and prep it for pulling out the primary key;
EOEntity fooE = EOModelGroup.globalModelGroup().entityNamed("Foo");
EOFetchSpecification fs = ...
fs.setFetchesRawRows(true);
fs.setRawRowKeyPaths(fooE.primaryKeyAttributeNames());
By doing this, you don't give EOF so much work to do ensuring the
EO's you are working with are unique. OK so now fetch this into an
NSArray...
NSArray rrs = null;
{
EOEditingContext ec = new EOEditingContext();
ec.lock();
try { rrs = ec.objectsWithFetchSpecification(); }
finally { ec.unlock(); }
}
...work through these raw rows 50 (as an example) at a time...
for(int i=0;i<rrs.count();i+=50)
{
NSMutableArray<EOQualifier> qs = new NSMutableArray<EOQualifier>();
for(int j=i;(j<(i+50)) && (j<rrs.count());j++)
{
EOGlobalID gid = fooE.globalIDForRow((NSDictionary)
rrs.objectAtIndex(j));
qs.addObject(LEEOHelper.qualifierForGlobalID(gid)); <--- copy
this method from LEWOStuff source.
}
EOEditingContext ec = new EOEditingContext();
ec.lock();
try
{
EOFetchSpecification fs = new EOFetchSpecification("Foo",new
EOOrQualifier(qs),null);
...fetch those EO's and do some stuff with them...
}
finally { ec.unlock(); }
}
...hope this helps and post back to the list (CC me) if you are
confused.
cheers.
Yes, I saw your post. However, I'm not an advanced EOF user, nor
do I know SQL very well (it's one of the reason I like
webobjects). That and the fact that any change I make needs to be
working in a couple of weeks makes me want to save a change like
you suggest for later when I've got more time to come up to speed
and to test. Maybe it's not as hard as it sounds? Keep in mind
that right now when you say "Load the list of EO's into memory to
be processed as raw-rows with the PK in the raw rows." I have NO
idea what you're talking about.
___
Andrew Lindesay
www.lindesay.co.nz
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--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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