Re: caching
Re: caching
- Subject: Re: caching
- From: Sacha Mallais <email@hidden>
- Date: Wed, 11 May 2005 11:18:23 -0700
On May 11, 2005, at 10:58 am, Mike Schrag wrote:
So the problem is that these are top level objects, so there's no
relationship I can traverse to get to them, which means that while the
row itself may come from the snapshot, a query is still executed to
retrieve the ID. And on any given page, I have to resolve as many as
40 of these by their Name field (for several technical reasons, the
EO's have to be looked up by name and can't exist as relationships
from the container EO). So every page kicking off 40 queries,
regardless of whether they pull the data or not, is pretty painful.
If you are accessing them by the FK (which it appears that you're not,
from what you said below), then you can get a fault from a global id
(that you would construct).
Since it appears that you're bypassing EOF completely here, you could
create your own cache in, for example, the session, and fault the
objects into the needed EC instead of fetching them every time. But
I'm assuming that this data is "lookup" data. If you have 40 unique
eos attached to an entity without a relationship then you could create
an ivar in the entity class to hold them.
sacha
On May 11, 2005, at 1:37 PM, Sacha Mallais wrote:
On May 11, 2005, at 10:22 am, Mike Schrag wrote:
So I have a case where one of my EO's has a unique key which can't
be the primary key (it's changeable), but it is effectively the
primary key (that is, the EO is almost always looked up by that
key). I end up very frequently doing a qualifier on that field.
What is the recommended way to avoid hitting the database constantly
for these things? I would love to turn on Cache in Memory, but we
saw where that led me on the last situation (Incidentally, i tried
it again on this EO and it fails in the same way, which is to say,
it does nothing :) ). So what I really want here is a
most-recently-used cache mapped by the unique key. However,
properly implementing this without stepping on EOF's toes appears
that it might be really tricky (these EO's get updated and are
referenced by and from other EO's). Any suggestions or anyone run
into a similar problem?
Sounds like you should just be using the standard EOF caching. EOF
keeps a copy of your object's data in a cache called the snapshot.
If you _fetch_ data (via an EOFetchSpecification), EOF will go to the
database, but if you fire a fault (by traversing a relationship, for
example), EOF will only go to the database if the data does not
already exist in the snapshot.
HTH,
sacha
--
Sacha Michel Mallais - 400 lb. chimp
Global Village Consulting Inc.: http://www.global-village.net/
Choke on that, causality! -- the Professor, "Futurama"
--
Sacha Michel Mallais - 800 lb. gorilla
Global Village Consulting Inc.: http://www.global-village.net/
Bottom posting is your friend:
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| References: | |
| | >caching (From: Mike Schrag <email@hidden>) |
| | >Re: caching (From: Sacha Mallais <email@hidden>) |
| | >Re: caching (From: Mike Schrag <email@hidden>) |