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Native Hibernate query works very slow from the application but very fast when I run it directly from MySQL workbench

In my application I use native query to fetch data:
SELECT
time_month,
CCC.closing_strike_value AS closing_strike_value,
CC.opening_strike_value AS opening_strike_value,
C.closing_time AS closing_time,
C.max_ask AS max_ask,
C.max_bid AS max_bid,
C.max_point_value AS max_point_value,
C.max_strike_value AS max_strike_value,
C.min_ask AS min_ask,
C.min_bid AS min_bid,
C.min_point_value AS min_point_value,
C.min_strike_value AS min_strike_value,
C.opening_time AS opening_time,
C.option_name AS option_name,
C.opening_time AS id
FROM
(SELECT
DATE(DATE_FORMAT(FROM_UNIXTIME(opening_time / 1000), '%Y-%m-01')) AS time_month,
MAX(closing_time) AS closing_time,
MAX(max_ask) AS max_ask,
MAX(max_bid) AS max_bid,
MAX(max_point_value) AS max_point_value,
MAX(max_strike_value) AS max_strike_value,
MIN(min_ask) AS min_ask,
MIN(min_bid) AS min_bid,
MIN(min_point_value) AS min_point_value,
MIN(min_strike_value) AS min_strike_value,
MIN(opening_time) AS opening_time,
option_name
FROM
candle_option
WHERE
option_name LIKE CONCAT('%', :optionName, '%')
AND opening_time BETWEEN :from AND :to
GROUP BY DATE(DATE_FORMAT(FROM_UNIXTIME(opening_time / 1000), '%Y-%m-01'))) C
JOIN
candle_option CC ON CC.opening_time = C.opening_time
AND CC.option_name = C.option_name
JOIN
candle_option CCC ON CCC.closing_time = C.closing_time
AND CCC.option_name = C.option_name
ORDER BY C.opening_time
Every column listed in the first select statement corresponds to a field within the Entity which I retrieve.
This native query works fine and returns valid results. However, there is one crucial problem - it fetches results dramatically slow even on small amounts of data when used by hibernate. However, when I run this query directly (I use MySQL Workbench) results are returned very fast. For instance, if this query is executed by hibernate, It takes about about 1 minute to get results; if I run this query directly from MySQL Workbench, then it takes only 100 milliseconds.
I wonder why is this happening and would appreciate any hint or help.
Thanks!

Delete from table on same select same table mariadb using jpa

I need delete from table on operation of same table .JPA query is
DELETE FROM com.model.ElectricityLedgerEntity a
Where a.elLedgerid IN
(SELECT P.elLedgerid FROM
(SELECT MAX(b.elLedgerid)
FROM com.model.ElectricityLedgerEntity b
WHERE b.accountId='24' and b.ledgerType='Electricity Ledger' and b.postType='ARREARS') P );
I got this error:
with root cause org.hibernate.hql.ast.QuerySyntaxException: unexpected
token: ( near line 1, column 109 [DELETE FROM
com.bcits.bfm.model.ElectricityLedgerEntity a Where a.elLedgerid IN (
SELECT P.elLedgerid FROM ( SELECT MAX(b.elLedgerid) FROM
com.bcits.ElectricityLedgerEntity b WHERE b.accountId='24'
and b.ledgerType='Electricity Ledger' and b.postType='ARREARS') P ) ]
at
org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54)
at
org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:47)
at
org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:82)
at
org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:284)
Same query is running on mysql terminal ,but this is not working with jpa .Can any one tell me how i can write this query using jpa .

I don't understand why do you use Pbefore the last parenthesis...
The following code is not enough ?
DELETE FROM com.model.ElectricityLedgerEntity a
Where a.elLedgerid IN
(SELECT MAX(b.elLedgerid)
FROM com.model.ElectricityLedgerEntity b
WHERE b.accountId='24' and b.ledgerType='Electricity Ledger' and
b.postType='ARREARS')
Edit for bypassing mysql subquery limitations :
The new error java.sql.SQLException: You can't specify target table 'LEDGER' for update in FROM clause
is known in mysql when you use it with JPA. It's one MySQL limitation.
A recent stackoverflow question about it
In brief, you cannot "directly" updated/deleted a table that you query in a select clause
Now I understand why your original query did multiple subqueries seemingly not necessary (while it was useful for mysql) and had a "special" syntax.
I don't know tricks to solve this problem in JPA (I don't use the MySQL DBMS for a long time now).
At your place, I would do two queries. The first where you select the expected max elLedgerid and the second where you could delete line(s) with the id retrieved in the previous query.
You should not have performance issues if your sql model is well designed, the sql indexes well placed and the time to access to the database is correct.

You cannot do this in a single query with Hibernate. If you want to delete the max row(s) with Hibernate you will have to do so in two steps. First, you can find the max entry, then you can delete using that value in the WHERE clause.
But the query you wrote should actually run as a raw MySQL query. So why don't you try executing that query as a raw query:
String sql = "DELETE FROM com.model.ElectricityLedgerEntity a " +
"WHERE a.elLedgerid IN (SELECT P.elLedgerid FROM " +
"(SELECT MAX(b.elLedgerid) FROM com.model.ElectricityLedgerEntity b " +
"WHERE b.accountId = :account_id AND b.ledgerType = :ledger_type AND " +
" b.postType = :post_type) P );";
Query query = session.createSQLQuery(sql);
query.setParameter("account_id", "24");
query.setParameter("ledger_type", "Electricity Ledger");
query.setParameter("post_type", "ARREARS");

Just want to extend existing answer:
In brief, you cannot "directly" updated/deleted a table that you query in a select clause
This was lifted with starting from MariaDB 10.3.1:
Same Source and Target Table
Until MariaDB 10.3.1, deleting from a table with the same source and target was not possible. From MariaDB 10.3.1, this is now possible. For example:
DELETE FROM t1 WHERE c1 IN (SELECT b.c1 FROM t1 b WHERE b.c2=0);

java looping through multiple sql queries

I'm trying to loop through multiple sql queries that are executed. I want to first get all the question information for a certain task and then get the keywords for that question. I have three records in my Questions table, but when the while loop at the end of list.add(keyword); is done, it jumps to the SELECT Questions.Question loop (as it should) and then just jumps out and gives me only one record and not the other 2.
What am I doing wrong? Can someone maybe help me fix my code? I've thought of doing batch sql executes (maybe that is the solution), but within each while loop, I need information from the previous sql statement, so I can't just do it all at the end of the batch.
SQL Code:
String TaskTopic = eElement.getElementsByTagName("TaskTopic").item(0).getTextContent();
// perform query on database and retrieve results
String sql = "SELECT Tasks.TaskNo FROM Tasks WHERE Tasks.TaskTopic = '" + TaskTopic + "';";
System.out.println(" Performing query, sql = " + sql);
result = stmt.executeQuery(sql);
Document doc2 = x.createDoc();
Element feedback = doc2.createElement("Results");
while (result.next())
{
String TaskNo = result.getString("TaskNo");
// perform query on database and retrieve results
String sqlquery = "SELECT Questions.Question, Questions.Answer, Questions.AverageRating, Questions.AverageRating\n" +
"FROM Questions\n" +
"INNER JOIN TaskQuestions ON TaskQuestions.QuestionID = Questions.QuestionID \n" +
"INNER JOIN Tasks ON Tasks.TaskNo = '" + TaskNo + "';";
result = stmt.executeQuery(sqlquery);
while (result.next())
{
String Question = result.getString("Question");
String Answer = result.getString("Answer");
String AverageRating = result.getString("AverageRating");
String sqlID = "SELECT QuestionID FROM Questions WHERE Question = '" + Question + "';";
result = stmt.executeQuery(sqlID);
while (result.next())
{
String ID = result.getString("QuestionID");
String sqlKeywords = "SELECT Keyword FROM LinkedTo WHERE QuestionID = '" + ID + "';";
result = stmt.executeQuery(sqlKeywords);
while (result.next())
{
String keyword = result.getString("Keyword");
list.add(keyword);
}
}
feedback.appendChild(x.CreateQuestionKeyword(doc2, Question, Answer, AverageRating, list));
}
}

Why this should be done in SQL
Creating loops is exponentially less efficient than writing a sql query. Sql is built to pull back this type of data and can plan out how it is going to get this data from the database (called an execution plan).
Allowing Sql to do its job and determine the best way to pull back the data instead of explicitly determining what tables you are going to use first and then calling them one at a time is better in terms of the amount of resources you will use, how much time it will take to get the results, code readability, and maintainability in the future.
What information you are looking for
In the psuedocode you provided, you are using the Keyword, Question, Answer, and AnswerRating values. Finding these values should be the focus of the sql query. Based on the code you have written, Question, Answer, and AnswerRating are coming from the Questions table and Keyword is coming from the LinkedTo table, so both of these tables should be available to have data pulled from them.
You can note at this point that we have essentially just mapped out what the Select and From portions of your query should look like.
It also looks like you have a parameter called TaskTopic so we need to include the table Tasks to make sure the correct data is returned. Lastly, the TaskQuestions table is the link between the tasks and the questions. Now that we know what the query should look like, let's see what the results are using sql syntax.
The Code
You did not include the declaration of stmt, but I assume that it is a PreparedStatement. You can add parameters to a prepared statement. Notice the ? in the sql code? The parameters you provide will be added in place of the ?. To do this, you should use stmt.setString(1, TaskTopic);. Note that if there were more than one parameter, you would need to add them in the order that they exists in the sql query (using 1, 2, ...)
SELECT l.Keyword,
q.Question,
q.Answer,
q.AverageRating
FROM LinkedTo l Inner Join
Questions q
on l.questionID = q.QuestionID
Where exists ( Select 1
From TaskQuestions tq INNER JOIN
Tasks t
on tq.TaskNo = t.TaskNo
Where t.TaskTopic = ?
and tq.QuestionID = q.QuestionID)
This is one way that you can write the query to return the same results. There are other ways to write this to get what you are looking for.
What's Going On?
There are a few things in this query you may not be familiar with. First are table aliases. Instead of writing the table name over and over again, you can alias your tables. I used the letter q to represent the Questions table. Any time you see q. you should recognize that I am referring to a column from Questions. The q after Questions is what gives the table its alias.
Exists Instead of doing a bunch of inner joins with tables that you are not selecting information from, you can use an exists to check if what you are looking for is in those tables. You can continue to do inner joins if you need data from the tables, but if you don't, Exists is more efficient.
I suspect you had issues with the query before (and probably the one you provided) because you did not provide any information to join TaskQuestions and Tasks together. That most likely resulted in the duplicates. I joined on TaskNo but this may not be the correct column depending on how the tables are set up.

Hibernate HQL setMaxResults does not work?

I'm building a small program in Java Hibernate handling a subpart of the DBLP database (parsed from XML into a SQL db).
I've queries manipulating big chuncks of data so I want to limit the output result to 10 so it goes faster.
Query query = this.session.createQuery("select A.author_id "
+ "from publication as P "
+ "join P.authors as A "
+ "where P.year <= 2010 and P.year >= 2008 "
+ "group by A.author_id "
+ "having count(distinct P.year) = 3");
query.setMaxResults(10);
this.authors = query.iterate();
That piece of code is supposed to retrieve all the authors who published at least once every year between 2008 and 2010 included.
My problem is that the line "query.setMaxResults(10);" simply does not have effect, the SQL command generated by Hibernate is
select author2_.Author_id as col_0_0_ from publication publicatio0_ inner join author_publication authors1_ on publicatio0_.Publication_ID=authors1_.publication_id inner join author author2_ on authors1_.author_id=author2_.Author_id where publicatio0_.Year<=2010 and publicatio0_.Year>=2008 group by author2_.Author_id having count(distinct publicatio0_.Year)=3
limit ?
Remarque the "limit ?" at the end.
So my question is simple, how do I use properly setMaxResults to get a correct SQL Limit ?
EDIT: all the limit stuff works fine, I misunderstood the use of limit in SQL, what I'm looking for is a way to stop the execution of the query after a given number of rows corresponding to the conditions is found, so that it does not take days to get thousands useless rows but simply returns the 10 first found rows for example.
Thanks in advance !

how to find difference between two timestamp using hibernate query language

I am trying to write an hql query which gives me the number of hours between two timestamp.
So, far i am unable to do this. I have used hql hour function but that does not work if the
timestamp corresponds to different date. Please provide any input.
My hql query is
select count(*) from com.xxx.Request as request where request.id = :id and hour(current_timestamp - request.lastEventDate) > :delay

well, you can use:
days(first_timestamp) * 24 + hours(first_timestamp)
- days(second_timestamp) * 24 - hours(second_timestamp);