Thanks for your suggestion. I have created the issue DRILL-4157.
In the mean time I will use your workaround. Regards, Daniel García Continuous Improvement Team Albasanz 12 / 4th Floor / 28037 Madrid T +34 917 542 966 E [email protected] W www.eurotaxglass.com -----Mensaje original----- De: Magnus Pierre [mailto:[email protected]] Enviado el: jueves, 3 de diciembre de 2015 11:56 Para: [email protected] Asunto: Re: LIMIT clause not being sent to MySQL server Hello Daniel, Your understanding is perfectly correct. Drill does support translation of SQL to native SQL provided rules exists for that. One could write a push down rule for handling LIMIT based on DB type and by that get it pushed down. (Not being a core developer so I don’t want to describe how, since I am bound to get it wrong :)) So check with the team if LIMIT should be pushed down based on existing rules (my guess is no), and possibly open a JIRA for its inclusion. The simplest way to simulate the behavior is to do a limited view in the DB which is basically selecting with limit and use that as your source table. Not pretty but very straightforward. Best regards, Magnus > 3 dec 2015 kl. 11:39 skrev Daniel Garcia <[email protected]>: > > Hello Magnus, > > Thanks for your answer. > > I understand the issue regarding non-standard SQL for LIMIT and OFFSET > clauses. But I thought that apache drill, somehow, was able to translate this > into native SQL (In MySQL case, the LIMIT clause is exactly the same). > > Anyway, any idea to achieve the same?? The table is very big and I cannot > afford to retrieve all rows. > > Regards, > > > Daniel García > Continuous Improvement Team > > > > Albasanz 12 / 4th Floor / 28037 Madrid > > T +34 917 542 966 > > E [email protected] <mailto:[email protected]> > W www.eurotaxglass.com <http://www.eurotaxglass.com/> > > -----Mensaje original----- > De: Magnus Pierre [mailto:[email protected] > <mailto:[email protected]>] Enviado el: jueves, 3 de diciembre de > 2015 10:50 > Para: [email protected] <mailto:[email protected]> > Asunto: Re: LIMIT clause not being sent to MySQL server > > Hello Daniel, > > Filters and joins are pushed down i.e. filters on column data. Limit is a > special keyword not always supported by a database (different syntaxes for > quite many databases) and as such I don’t think the push down rules works for > that. > > Regards, > Magnus > > > >> 3 dec 2015 kl. 10:00 skrev Daniel Garcia <[email protected]>: >> >> Hi, >> >> I’m trying to obtain just one row from a table stored in MySQL by using the >> following query: >> >> select * from my.schema.table limit 1; >> >> But I’m not getting just one row but all instead. I mean: apache drill only >> shows one line, but it retrieves all of them from the source. >> >> Looking at the query being executed in MySQL server I can see that the >> “limit 1” part is not sent. >> Can apache drill filter data in the source rather than extract all rows in >> memory and then filter them? >> >> I’m using: >> jdk build 1.7.0_79-b15 >> apache drill 1.3 >> mysql-connector-java 5.1.37 >> windows 10 >> >> Regards, >> >> Daniel García >> Continuous Improvement Team >> >> >> >> Albasanz 12 / 4th Floor / 28037 Madrid >> >> T +34 917 542 966 >> >> E [email protected] <mailto:[email protected]> >> <mailto:[email protected] >> <mailto:[email protected]>> >> W www.eurotaxglass.com <http://www.eurotaxglass.com/> >> <http://www.eurotaxglass.com/ <http://www.eurotaxglass.com/>> >> >> >> >> Disclaimer >> >> The information contained in this communication from the sender is >> confidential. It is intended solely for use by the recipient and others >> authorized to receive it. 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