About MIN


GROUP BY and HAVING clauses

Explains how to use the GROUP BY and HAVING clauses in a JPA/JPQL query.... Aggregate calculations (count, sum, avg, max, min) that are carried out on all the objects (or the object tuples) in the ... of numeric values as a double value. MIN - returns the minimum of comparable values (numeric, strings, dates). ...



Create an aggregate expression applying the numerical min operation.(Method of javax.persistence.criteria.CriteriaBuilder)


High memory consumption even after close() of EntityManagerFactory

Hello, we still have memory usage problems. When debugging, we have now observed a case in which the execution of multiple queries increasingly byte array were generated (about 1.5 GB) which from GC could not be released. Not even after the EntityManagerFactory closed. We created a small test with which you can observe similar behavior. The huge memory usage only occurs if we execute the query (line 56 to 61). If we remove this query, all is well. The memory is only released after we re-run a query (on a different database). ... For execution the VM Heap must have min. 1280MB edit ...


JPA Query Structure (JPQL / Criteria)

Explains the structure of a JPQL query, which consists of 6 clauses: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY.... operation. See JavaDoc Reference Page... , min min(x) CriteriaBuilder's method Create an aggregate expression ...


JPA Criteria API Queries

Explains how to use the JPA Criteria API (CriteriaBuilder, CriteriaQuery, etc.) to build JPQL like queries.... operation. See JavaDoc Reference Page... , min min(x) CriteriaBuilder's method Create an aggregate expression ...


Comparison in JPQL and Criteria API

Explains how comparison operators can be used in JPQL queries, including in comparing null values.... The two following expressions are equivalent ( :min and :max are query parameters ): x BETWEEN :min AND :max   x >= :min AND x <= :max ...



Used to construct criteria queries, compound selections, expressions, predicates, orderings.(Interface of JPA)


Index Definition

Describes how to define indexes in JPA entity classes and explains how indexes are used in JPQL queries.... for sorting results and for projection: SELECT MIN ( p . x ) FROM Point p WHERE p . x < p . ... for a separate sort. Finally, indexes are also used in MIN and MAX queries: SELECT MIN ( p . x ) , MAX ...


Queries are slow on a large database

Hi, I have a 12GB database with 787603 entries. It is much larger than usual and there are performances issues. I am doing small queries and they take much longer than I expect, i.e.: Get the total number of entries Get 25 consecutive entries (i.e. 0-25) Get one specific entry On average each query needs 4 to 5 minutes to return a result. I have been adviced to use indexes but they are already used through the JDO Metadata file. For instance I use this class: ... very fast execution time. Similarly to get MAX/MIN values: SELECT MAX ( m . id ) FROM ... class ) ; query. setResult ( "min(this.Id), max(this.Id), count(this.Id)" ) ; Object [ ...


Pessimistic lock timeout - blocks indefinitely

I've attached a simple test which creates an object then kicks off several threads which each try to update the object. I'm using a pessimistic lock with timeout as follows: ... longer than 5000ms at least - I killed the test after a min or so). If I set the timeout to less than 1000ms the blocked ...