Re: EO Caching
Re: EO Caching
- Subject: Re: EO Caching
- From: Paul Hertz <email@hidden>
- Date: Mon, 10 Dec 2007 17:58:21 -0600
At 10:41 AM -0800 12/7/07, Chuck Hill wrote:
On Dec 7, 2007, at 7:01 AM, Jeffrey Simpson wrote:
I want to preload some EOs and so they are cached. I have set
ERXEC.setDefaultFetchTimestampLag(86400000);
That only applies to faulting, not fetching. You might want to look
at the much feared EOSharedEditingContext or at Wonder's EO caching
classes (there are three or so, IIRC). Also look at the "Cache in
memory" setting in EOModeler.
I preload my EOs and do some
batch fetching. Later on I use a fetch spec to query from the database some
of the cached EOs. They are fully fetched which I understand is the case.
When I then batch fetch these EOs the system always runs fetches.
It is not clear to me what code you are using here. I will note
that all fetches (ec.objectsWithFetchSpecification) go to the
database, even if the fetched data is then discarded. Batch
fetching is a fetch.
As I understand it (more foggy than I'd like), the record from the
database will be discarded if the global ID that gets generated for
the fetched row corresponds to an object in the editing context that
is not a fault. In that case, the object from the editing context is
returned. That should save some computational time (yes?), but
clearly not as much as if one knows the object is already in memory
and uses it without calling objectsWithFetchSpecification. Especially
not the case if the WO server and the database server are separate
machines, and time is taken up by network communications.
The time
between this fetch and the preloading is < 5 minutes. If I run the same
query in a the same ec then the EOs are cached. Any idea of why there is no
caching between the 2 ecs?
No, not without a clearer understanding of your code.
Chuck
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Paul Hertz <email@hidden>
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