Ok, this is pushed to master. All 3 styles are implemented. See issue for details.
On Thu, Nov 1, 2012 at 2:43 PM, Steve Ebersole <st...@hibernate.org> wrote: > fwiw... I have a lot of this implemented locally. At the moment it is > "swappable", but I have not yet exposed this as a setting. Also, I only > have (1) and (2) implemented. (2) is implemented by padding with the main > identifier that triggered the batch load. > > Plan is to work on (3) tomorrow, if I do not get to it today. > > https://hibernate.onjira.com/browse/HHH-7746 is the issue I am working for > this. > > > On Thu 01 Nov 2012 10:04:03 AM CDT, Steve Ebersole wrote: >> >> Just to clarify... (3) is not building the entire statement. Most of >> the statement can be pre-built. It just needs to append the proper >> IN-condition >> >> On Thu 01 Nov 2012 09:30:41 AM CDT, Steve Ebersole wrote: >>> >>> Maybe its best to make this configurable too? >>> >>> I can see 3 selections: >>> 1) current algorithm - the current code as is >>> 2) current size break down but with padding - the current code except >>> selecting the next higher batch size and padding extras (current code >>> selects next smaller size, iteratively) >>> 3) dynamic - dynamically build the batch statement >>> >>> wdyt? >>> >>> On Tue 30 Oct 2012 02:28:31 PM CDT, Steve Ebersole wrote: >>>> >>>> Well the other option is to not pre-build/cache the statements for the >>>> batch sizes. That would free up memory as well as reduce the number >>>> of queries to just one, with the offset being the need to build the >>>> SQL dynamically (although most of it could be built up front). >>>> >>>> >>>> On 05/08/2012 02:06 AM, Clemens Eisserer wrote: >>>>> >>>>> Hi Guenther, >>>>> >>>>>>>> Is it possible to disable prepared statement caching for batched >>>>>>>> fetching, so I end up with a single query in the < >>>>>>>> default_batch_fetch_size case only >>instead of the >>>>>>>> fixed-size batch loading hibernate does by default? >>>>> >>>>> >>>>>> I think the main reason for no feedback so far, is that nobody was >>>>>> able to understand this sentence. >>>>>> Usually 'prepared statement caching' is a synonym to 'prepared >>>>>> statement pooling' and is something which has to be provided by a >>>>>> connection-pool (or a jdbc-driver) and thus >>>>>> Hibernate does actually not implement any prepared statement >>>>>> cache/pooling. >>>>>> Can you please explain what you intend under 'prepared statement >>>>>> caching'? >>>>>> Can you also please try to better explain the second part of your >>>>>> sentence? >>>>> >>>>> >>>>> Sorry for beeing that cryptic, I will try to rephrase it: >>>>> >>>>> When Hibernate does batch-fetching, it generates PreparedStatements >>>>> for certain batch sizes - for a batch_size of 50, the prepared >>>>> statements for batch-sizes will have the following sizes: >>>>> [1,2,3,4,5,6,7,8,9,10,12,25,50]. When e.g. a batch of size 13 should >>>>> be fetched, because of the fixed size of the prepared statements, 3 >>>>> queries are issued for batch-fetching, although 13 <= 50. In this case >>>>> the 3 batches would be of the size 13 = 8 + 4 + 1. >>>>> In a latency bound (between db and application) environment, this >>>>> serverly hampers response time - instead of a single round-trip to do >>>>> the batched fetch, Hibernate requires 3. >>>>> (subselect can't be used in my case, because my queries are already >>>>> rather complex, and the added complexity confuses the DBs query >>>>> planner too much) >>>>> >>>>> What I did in this case (only for integer PKs) is to pad up to the >>>>> next batch size with a non-existant PK. >>>>> So, for the example mentioned above, I can use the PreparedStatement >>>>> with size 25, and insert padding from 14-25, which will make the query >>>>> slightly more inefficient but avoid 2 additioan round-trips. >>>>> >>>>> - Clemens >>>>> _______________________________________________ >>>>> hibernate-dev mailing list >>>>> hibernate-dev@lists.jboss.org >>>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev >>>>> >>>> >>> >>> -- >>> st...@hibernate.org >>> http://hibernate.org >> >> >> -- >> st...@hibernate.org >> http://hibernate.org > > > -- > st...@hibernate.org > http://hibernate.org _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
