> My intention was to separate the local and shared query caches while not
> eliminating either, so that is the reason both are used. So if you have
> explicitly set a custom localQueryCache then calling getQueryCache() will
> allow you to still access the *shared* query cache as well.
But this is called by the framework, not the user. And from what I see, some of
Cayenne code calls the former, and other - the later.
I general I am thinking we should make the type of per-context QueryCache a
property of the entire runtime (it is either a segment of the main cache, or a
separate per-context object ... either one or the other for all contexts). Is
this too limiting?
Andrus
> On Jul 3, 2019, at 5:34 PM, John Huss <johnth...@gmail.com> wrote:
>
> On Wed, Jul 3, 2019 at 5:33 AM Andrus Adamchik <and...@objectstyle.org>
> wrote:
>
>> Hi John,
>>
>> I think I understand where you are going with this feature. As we
>> discussed before, sometimes keeping a context cache as a transparent region
>> of the main cache is undesirable, e.g. for memory management reasons. But I
>> have some questions about the implementation committed to "master":
>>
>> 1. The commit seems incomplete - sometimes we use the new
>> "getLocalQueryCache()", sometimes - the old "getQueryCache()".
>>
>
> My intention was to separate the local and shared query caches while not
> eliminating either, so that is the reason both are used. So if you have
> explicitly set a custom localQueryCache then calling getQueryCache() will
> allow you to still access the *shared* query cache as well.
>
>
>
>> 2. Having both "queryCache" and "localQueryCache" as ivars of BaseContext
>> may be confusing. What do you think of moving cache type selection logic in
>> ObjectContextFactory?
>>
>
> Do you mean exposing this in the API of the interface? Currently I am
> configuring this with a DataContextFactory subclass like this:
>
> *public* *static* *class* Factory *extends* DataContextFactory {
>
> @Override
>
> *protected* DataContext newInstance(DataChannel parent, ObjectStore
> objectStore) {
>
> *return* *new* IcsDataContext(parent, objectStore);
>
> }
>
> @Override
>
> *protected* ObjectContext createdFromDataDomain(DataDomain parent) {
>
> DataContext result = (DataContext) *super*.createdFromDataDomain(parent);
>
> result.setLocalQueryCache(*new* MapQueryCache(Integer.*MAX_VALUE*)); // use
> separate unbounded cache whose lifetime is bound to the ObjectContext itself
>
> *return* result;
>
> }
>
> @Override
>
> *protected* ObjectContext createFromDataContext(DataContext parent) {
>
> DataContext result = (DataContext) *super*.createFromDataContext(parent);
>
> result.setLocalQueryCache(*new* MapQueryCache(Integer.*MAX_VALUE*));
>
> *return* result;
>
> }
>
> @Override
>
> *protected* ObjectContext createFromGenericChannel(DataChannel parent) {
>
> DataContext result = (DataContext) *super*.createFromGenericChannel(parent);
>
> result.setLocalQueryCache(*new* MapQueryCache(Integer.*MAX_VALUE*));
>
> *return* result;
>
> }
>
> }
>
> I'm open to other ways of configuring this if you have ideas, perhaps like
> using DI. Thanks for your feedback.
>
>
>
>>
>> Thanks,
>> Andrus
>>
>>
>>> On Jul 1, 2019, at 5:53 PM, johnth...@apache.org wrote:
>>>
>>> This is an automated email from the ASF dual-hosted git repository.
>>>
>>> johnthuss pushed a commit to branch master
>>> in repository https://gitbox.apache.org/repos/asf/cayenne.git
>>>
>>>
>>> The following commit(s) were added to refs/heads/master by this push:
>>> new 597376a CAY-2589 Allow optionally using a local query cache
>> that is separate from the shared query cache.
>>> 597376a is described below
>>>
>>> commit 597376ae558b9a0c5ddc4390da188b9530204e3d
>>> Author: John Huss <johnth...@apache.org>
>>> AuthorDate: Mon Jun 3 16:57:20 2019 -0500
>>>
>>> CAY-2589 Allow optionally using a local query cache that is separate
>> from the shared query cache.
>>>
>>> The local query cache can be customized by creating a custom
>> DataContextFactory.
>>>
>>> A separate cache can prevent memory leaks from occurring if you used
>> non-expiring cache
>>> groups (like the default cache group perhaps) along with the local
>> cache, which wasn't
>>> intuitive if you expected the lifetime of the cache to match the
>> lifetime of the ObjectContext.
>>> ---
>>> RELEASE-NOTES.txt | 1 +
>>> .../main/java/org/apache/cayenne/BaseContext.java | 27
>> +++++++++++++++++++++-
>>> .../cayenne/util/ObjectContextQueryAction.java | 9 +++++++-
>>> 3 files changed, 35 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
>>> index 6f45986..3aa2fa8 100644
>>> --- a/RELEASE-NOTES.txt
>>> +++ b/RELEASE-NOTES.txt
>>> @@ -36,6 +36,7 @@ CAY-2569 Custom 'Naming Strategy' in Cayenne Modeler
>>> CAY-2570 Use MySQL adapter for latest versions of MariaDB
>>> CAY-2579 Review and possibly relax usage of readonly flag of
>> ObjRelationship
>>> CAY-2585 Rename scalarQuery and params methods in SQLSelect
>>> +CAY-2589 - Allow optionally using a local query cache that is separate
>> from the shared query cache.
>>>
>>> Bug Fixes:
>>>
>>> diff --git
>> a/cayenne-server/src/main/java/org/apache/cayenne/BaseContext.java
>> b/cayenne-server/src/main/java/org/apache/cayenne/BaseContext.java
>>> index 981db73..ffae953 100644
>>> --- a/cayenne-server/src/main/java/org/apache/cayenne/BaseContext.java
>>> +++ b/cayenne-server/src/main/java/org/apache/cayenne/BaseContext.java
>>> @@ -98,6 +98,7 @@ public abstract class BaseContext implements
>> ObjectContext {
>>> // registry
>>> protected transient DataChannel channel;
>>> protected transient QueryCache queryCache;
>>> + protected transient QueryCache localQueryCache;
>>> protected transient EntityResolver entityResolver;
>>>
>>> protected boolean validatingObjectsOnCommit = true;
>>> @@ -469,17 +470,41 @@ public abstract class BaseContext implements
>> ObjectContext {
>>> @Override
>>> public abstract Collection<?> uncommittedObjects();
>>>
>>> + /**
>>> + * Used for storing cached query results available to all
>> ObjectContexts.
>>> + */
>>> public QueryCache getQueryCache() {
>>> attachToRuntimeIfNeeded();
>>> return queryCache;
>>> }
>>>
>>> /**
>>> - * Sets a QueryCache to be used for storing cached query results.
>>> + * Sets a QueryCache to be used for storing cached query results
>> available to all ObjectContexts.
>>> */
>>> public void setQueryCache(QueryCache queryCache) {
>>> this.queryCache = queryCache;
>>> }
>>> +
>>> + /**
>>> + * Used for storing cached query results available only to this
>> ObjectContext.
>>> + * By default the local query cache and the shared query cache
>> will use the same underlying storage.
>>> + *
>>> + * @since 4.2
>>> + */
>>> + public QueryCache getLocalQueryCache() {
>>> + attachToRuntimeIfNeeded();
>>> + return localQueryCache != null ? localQueryCache :
>> getQueryCache();
>>> + }
>>> +
>>> + /**
>>> + * Sets a QueryCache to be used for storing cached query results
>> available only to this ObjectContext.
>>> + * By default the local query cache and the shared query cache
>> will use the same underlying storage.
>>> + *
>>> + * @since 4.2
>>> + */
>>> + public void setLocalQueryCache(QueryCache queryCache) {
>>> + this.localQueryCache = queryCache;
>>> + }
>>>
>>> /**
>>> * Returns EventManager associated with the ObjectStore.
>>> diff --git
>> a/cayenne-server/src/main/java/org/apache/cayenne/util/ObjectContextQueryAction.java
>> b/cayenne-server/src/main/java/org/apache/cayenne/util/ObjectContextQueryAction.java
>>> index 75dbdfa..acef54e 100644
>>> ---
>> a/cayenne-server/src/main/java/org/apache/cayenne/util/ObjectContextQueryAction.java
>>> +++
>> b/cayenne-server/src/main/java/org/apache/cayenne/util/ObjectContextQueryAction.java
>>> @@ -360,7 +360,7 @@ public abstract class ObjectContextQueryAction {
>>> return !DONE;
>>> }
>>>
>>> - QueryCache queryCache = getQueryCache();
>>> + QueryCache queryCache = getLocalQueryCache();
>>> QueryCacheEntryFactory factory = getCacheObjectFactory();
>>>
>>> if (cache) {
>>> @@ -385,6 +385,13 @@ public abstract class ObjectContextQueryAction {
>>> protected QueryCache getQueryCache() {
>>> return ((BaseContext) actingContext).getQueryCache();
>>> }
>>> +
>>> + /**
>>> + * @since 4.2
>>> + */
>>> + protected QueryCache getLocalQueryCache() {
>>> + return ((BaseContext) actingContext).getLocalQueryCache();
>>> + }
>>>
>>> /**
>>> * @since 3.0
>>>
>>
>>
