Surely my question was not good and it brought some confusion. I need to access to the internal API because I'm using the H2 engine with plugged tables from a 3rd party system (not a database). Then I capture the users' queries just before invoke the 3rd party system and populate the plugged tables with the fetched data from the 3rd party system.... and some of those queries must be aborted if the users do not use the "indexes" in the right way.
Note: "indexes" are not indexes in the strict sense (defined on some columns of a table). They are columns that users MUST include in the where clause because are required by the 3rd party system API, but the users are free for not doing it. Hence, If I was able to get the Plan I could analyze the tables and the columns used by the users to filter data and validate them against the scheme and abort potential full scans against the 3rd party system, etc The best approach to achieve it is the execution plan as it knows the execution order for the tables a well as the columns used as filters for each table. I tried to resolve it by analyzing the query syntax with the Parser: get the all the conditions etc. but it is a weak way and pretty difficult due the complexity of the SQL syntax, so I discarded this approach, even more after i saw that the Explain command is able to do such job much better. Could you help please? Thanks, Pablo 2015-06-11 18:08 GMT+02:00 Thomas Mueller <[email protected]>: > Hi, > > I don't understand, you just call st.execute("explain select * from > table"). No need to use the internal API. > > Regards, > Thomas > > > On Thursday, June 11, 2015, Pablo Beltran <[email protected]> wrote: > >> Hi, >> >> i would like to get the same text jist like the H2 Web Console when a >> plan is explained (Pls, see the attached picture), but I did not get it yet >> unfortunately. >> >> >> >> Connection conn = .... >> >> >> Statment st = con.createStatment("SELECT * FROM TABLE"), >> st.executeQuery(); >> >> .... >> >> >> JdbcConnection jdbcConnection = (JdbcConnection) conn; >> Session session = (Session) jdbcConnection.getSession(); >> Command current = session.getCurrentCommand(); //this method has been >> added to the Session class. >> Parser parser = new Parser(session); >> Prepared prepared = parser.prepare(current.toString()); //SELECT * FROM >> TABLE >> Explain exp = new Explain(session); >> exp.setCommand(prepared); >> >> and next?? >> >> I've tried several things from here but without too much success. >> >> Any idea? >> >> Thanks in advance! >> Pablo. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "H2 Database" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/h2-database. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "H2 Database" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/h2-database/QQpyLqXHHtU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/h2-database. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/h2-database. For more options, visit https://groups.google.com/d/optout.
