On 10/08/16 10:49, Xu,Wenjian wrote:
Hi all,
MonetDB version: 11.23.7 Ubuntu version: 14.04
I created a new optimizer pipeline by adding an additional optimization step after 'default_pipe', i.e.: '*my_customized_pipe*'='optimizer.inline();optimizer.candidates();optimizer.remap();optimizer.costModel();optimizer.coercions();optimizer.evaluate();optimizer.pushselect();optimizer.aliases();optimizer.mitosis();optimizer.mergetable();optimizer.deadcode();optimizer.aliases();optimizer.constants();optimizer.commonTerms();optimizer.projectionpath();optimizer.deadcode();optimizer.reorder();optimizer.reduce();optimizer.matpack();optimizer.dataflow();optimizer.querylog();optimizer.multiplex();optimizer.generator();optimizer.profiler();optimizer.garbageCollector();*optimizer.customizedstep()*'
What I have done is:
- Create an empty optimizer step: -- 1.1 add /opt_customizedstep.c/h/ in package /monetdb/optimizer/*/, leave function body /OPTcustomizedstepImplementation() /empty/, /i.e. with one statement */return 0*/
/ -- /1.2 register the step by modifying /opt_wrapper.c /and/optimizer.mal/ 2) Add the definition of the new pipeline in /opt_pipes.c/ 3) Modify the configuration file to compile the added source files.
After re-build the system, I can enable the new optimizer pipeline by *set optimizer='my_customized_pipe'*. However, I have two issues:
i) using EXPLAIN statement, I found the MAL plan different from the one generated by 'default_pipe' (which should be the same since I did nothing in the added step?). Specifically, the plan seems to be not affected by /optimizer.reorder() /step, i.e., bat.new() and bat.append() instructions appear in the end of the plan.
1) make sure you restarted the server. 2) plans are cached, so if you attempt the following select count(*) from tables set optimizer='my_customized_pipe' select count(*) from tables
it still uses the default plan
Furthermore, the optimizer history is not saved unless you call DEBUG select....
ii) then I entered mdb mode by DEBUG statement. But it seems that some command did not work as before. For example, *help* command does not display all commands available; *optimizer* command does not display actions performed by each optimizer step.
What's wrong with my procedure to add a new optimizer pipeline? Any comment would be helpful.
Best regards, Wenjian
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