Re: misc/54213 (Significant performance degradation of whatis(1) after src/usr.sbin/makemandb/whatis.c,-r1.6)

[Abhinav Upadhyay <er.abhinav.upadhyay%gmail.com@localhost>]

On Sat, May 18, 2019 at 3:45 PM Leonardo Taccari <leot%netbsd.org@localhost> wrote:
>
> The following reply was made to PR misc/54213; it has been noted by GNATS.
>
> From: Leonardo Taccari <leot%NetBSD.org@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc:
> Subject: Re: misc/54213 (Significant performance degradation of whatis(1) after src/usr.sbin/makemandb/whatis.c,-r1.6)
> Date: Sat, 18 May 2019 12:11:47 +0200
>
>  Hello Abhinav,
>
>  abhinav%NetBSD.org@localhost writes:
>  > Synopsis: Significant performance degradation of whatis(1) after src/usr=
>  .sbin/makemandb/whatis.c,-r1.6
>  >
>  > State-Changed-From-To: open->feedback
>  > State-Changed-By: abhinav%NetBSD.org@localhost
>  > State-Changed-When: Sat, 18 May 2019 07:58:39 +0000
>  > State-Changed-Why:
>  > Could you give the committed changes a try and see if it improves things=
>  ?
>
>  Sure!
>
>  Redoing all the tests with whatis-1.5, whatis-1.7 and whatis-1.8.
>  First I've prepared a man.db prior today commit using a
>  `/tmp/man.conf.old', redoing the tests for whatis -r1.5 and -r1.7:
>
>   % time sh -c 'for i in $(seq 10); do { ./whatis-1.5 -C /tmp/man.conf.old =
>  foo 2>/dev/null; } done'
>   0.089u 0.234s 0:00.32 96.8%     50+1863k 0+0io 120pf+0w
>
>   % time sh -c 'for i in $(seq 10); do { ./whatis-1.7 -C /tmp/man.conf.old =
>  foo 2>/dev/null; } done'
>   28.916u 2.403s 0:31.31 100.0%   0+15k 0+0io 120pf+0w
>
>  ...then I've `cvs up' today changes, locally rebuilt makemandb and
>  whatis and prepared a man.db using a `/tmp/man.conf', tests for
>  whatis -r1.8:
>
>   % time sh -c 'for i in $(seq 10); do { ./whatis-1.8 -C /tmp/man.conf foo =
>  2>/dev/null; } done'
>   0.057u 0.269s 0:00.32 96.8%     50+1551k 0+0io 120pf+0w
>
>  So, yes, now the performance of -r1.8 are similar to the one of
>  whatis.c -r1.5, thank you!
>
>  I have also checked that the resulting man.db sizes are comparable
>  and they are both 42MB.
>

Great, thank you for verifying in detail :)
>
>  I think that whatis.c -r1.7 was accidentally reverted and case
>  insensitive searchs no longer works, e.g.:
>
>   % ./whatis-1.5 -C /tmp/man.conf.old ApRoPoS
>   ApRoPoS: not found
>   % ./whatis-1.7 -C /tmp/man.conf.old ApRoPoS
>   apropos(1) - search the complete content of all man pages
>   % ./whatis-1.8 -C /tmp/man.conf ApRoPoS
>   ApRoPoS: not found
>
>  Possible patch to reintroduce that:
>
>   <https://www.NetBSD.org/~leot/src-patches/whatis-nocase.patch>
>
>  If that's ok please let me know and I'll commit it (or feel free
>  to commit it directly!).

Yes, please commit it, thank you for noticing.
>
>  Apart that I think that also DBSCHEMA should be updated to document
>  `name_desc' attribute of `mandb_links' table.

Yes, good catch. If you get a chance do it or I will do when I get
back to my machine.

-
Abhinav