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[OGR] Reading TAB files using 3.6 is slower than 3.51 #154

Closed tbonfort closed 12 years ago

tbonfort commented 12 years ago

Reporter: dmorissette Date: 2002/05/22 - 15:04

> -----Original Message-----
> From: Daniel Morissette [SMTP:morissette@dmsolutions.ca]
> Sent: Tuesday, May 21, 2002 2:10 PM
> To:   craig.gould@bt.com
> Subject:      Re: [mapserver-users] Fwd: Win32 Nightly Build Binary
> 
> craig.gould@bt.com wrote:
> > 
> > Thanks for the link. The beta version is now running on my machine,
> although
> > it seems a little slower. Is it a debug version?
> 
> Well, this executable may contain debugging symbols, but I don't think
> there would be any debug stuff in the code that would justify a
> difference in speed.  The executable may be bigger than the one that you
> had got from UMN since ours contains almost every possible optional
> component, so there may be a difference in time to load the executable
> in memory.
> 
> Is it slower while reading TAB files, or while reading shapefiles, or
> something else?  It is always possible that a change was made to the TAB
> driver that would have had an impact on performance.  If you can provide
> a specific example with a sample data file and mapfile where speed
> varies between the two versions then we'll try to have a look.
> 
> Thanks for pointing this speed issue BTW... performance of the software
> is always very important to us.
tbonfort commented 12 years ago

Author: dmorissette Date: 2002/05/22 - 15:05

craig.gould wrote:
> 
> Daniel
> Here are some simple comparative figures between 3.51 and 3.6 for zooming in
> on a map several times until the maximum zoom is reached (zoomsize=2).
> 
> 3.6                     3.51
> -------         --------
> 0.929           0.781
> 1                       0.492
> 3.76            0.992
> 1.97            0.64
> 1.35            0.48
> 1.019           0.672
> 0.530           0.422
> 4.59            2.746   'Zoom reaches a new 10MB file
> 1.519           0.629
> 0.793           0.461
> 1.059           0.871
> 5.629           3.84    'Zoom reaches a new 70MB file
> 1.44            0.969
> 1.109           0.852
> 
> As you can see 3.51 is faster in every single case.
> Unfortunately I cannot send you the data files as they belong to my
> employer.
> They are all TAB files, ranging from 20k to 70MB in size.
> The scale of the numbers is similar for searching, zooming out and panning.
> 
> Craig.
>
tbonfort commented 12 years ago

Author: dmorissette Date: 2002/05/22 - 16:11

Note that teh 3.51 version that Craig was using was the Win32 nightly build from 
the UMN website dated Feb 6th 2002
tbonfort commented 12 years ago

Author: dmorissette Date: 2002/05/22 - 16:34

Assigned to Julien.

Other notes: Craig's mapfile uses only straight TAB files (no seamless or 
TABViews), most layers use STYLEITEM AUTO, and there is no reprojection going 
on.
tbonfort commented 12 years ago

Author: dmorissette Date: 2002/06/19 - 19:47

See bug 162 which has been filed about the same problem...

*** This bug has been marked as a duplicate of 162 ***