bugGNU Octave - Bugs: bug #47299, lookfor without doc-cache...


bug #47299: lookfor without doc-cache extremely slow, many warnings

Submitted by:  Mike Miller <mtmiller>
Submitted on:  Sun 28 Feb 2016 07:41:29 PM UTC  
Category:  Octave Function Severity:  1 - Wish
Priority:  5 - Normal Item Group:  Performance
Status:  None Assigned to:  None
Originator Name:  Open/Closed:  Open
Release:  dev Operating System:  Any

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Tue 01 Mar 2016 07:15:48 PM UTC, comment #4:

I may have been thinking of bug #44336, though that may not be exactly the same issue.

John W. Eaton <jwe>
Project Administrator
Tue 01 Mar 2016 06:30:28 PM UTC, comment #3:

Yes, I must have interrupted an initial lookfor followed by another and the warning state was not reset as you point out. Starting over and waiting for it to finish shows no warnings, so this can be closed. I can't seem to find this other bug report though.

Mike Miller <mtmiller>
Project Administrator
Mon 29 Feb 2016 09:00:27 PM UTC, comment #2:

The weirdness with warnings is apparently due to bugs with the way that the warning state is handled when reset. The lookfor function tries to set all warnings off, then they are reset with unwind_protect. I don't see warnings if I do the following when I first start Octave:

but that takes a long time, and if I interrupt it (thus triggering the unwind_protect block that attempts to reset the warning state) then try the lookfor command again, then I start to see warnings. If I interrupt again, I continue to see warnings, but this time with stack trace info for each warning that was not previously displayed.

I think we already have a bug report about warning state not being handled correctly.

John W. Eaton <jwe>
Project Administrator
Mon 29 Feb 2016 12:56:16 AM UTC, comment #1:

The slowness is expected. I notice it particularly when using run-octave because it ends up using the slow path even though the doc-cache exists (this is with docs enabled). The doc-cache does perform correctly after 'make install'.

Warnigs are a concern; I'd rather not see those. The ones quoted do look pretty minor.

Rik <rik5>
Project Administrator
Sun 28 Feb 2016 07:41:29 PM UTC, original submission:

The lookfor function normally relies on the doc-cache file that contains an index of all function docstrings.

When Octave is built with --disable-docs, the doc-cache file is not built and the lookfor function falls back to pulling the docstrings straight out of every function in the symbol table.

I just tested this and it is extremely slow (understandable for what it's doing), and produces a lot of the following warning messages:

I'm not at all sure at the moment what's causing these warnings, but it would probably be useful to improve the experience for people who rely on lookfor since there are screenfuls of these warning messages before any useful output is shown.

Mike Miller <mtmiller>
Project Administrator


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    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2016-03-01 jwe Open/ClosedClosed => Open
    2016-03-01 rik5 Open/ClosedOpen => Closed

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