[freetds] 0.91 freebcp performance
rrankins at gothamconsulting.com
Tue Jun 23 09:29:22 EDT 2015
I was thinking more deeply regarding fast bcp versus "slow" bcp beyond just whether there was an index or not.
Been working more in SQL Server these days and whether you get minimally logged bcp there depends on indexes, triggers, as well as the recovery model chosen.
Anyway, whether fast or slow bcp, I compared Sybase versus freebcp both with and without indexes on the table and 0.91 version of freebcp was considerably slower in both cases. Performance without indexes still was not acceptable.
I downloaded and built 0.95 last night and tested the freebcp included with that and that was just as fast (and possibly slightly faster) than the Sybase bcp.
So now I guess it may be a matter of convincing them to switch to 0.95, but they are pretty far along in their testing cycle, so it might not be feasible at this point as they'd probably have to go back and regression test everything again.
> -----Original Message-----
> From: FreeTDS [mailto:freetds-bounces at lists.ibiblio.org] On Behalf Of David
> Sent: Monday, June 22, 2015 2:47 PM
> To: FreeTDS Development Group
> Subject: Re: [freetds] 0.91 freebcp performance
> I don't use freebcp, but for Sybase bcp, it runs the fast bcp
> (non-logged) if you don't have any indexes on the table. Thus, for
> large tables, we usually drop the indexes, run the bcp, then create the
> indexes again.
> However, if you are running freebcp and Sybase bcp on the same exact
> client and server with the same exact bcp import file to the same exact
> database table, I think you've uncovered a bug in freebcp.
> Your table is very narrow (less than 100 bytes wide). You have very
> little data (5M rows). I would expect to insert this amount of data
> into Sybase in about a minute.
> To test out the fast bcp versus slow bcp, I would create a new table
> with the same table structure (but no indexes) and test out freebcp
> against it.
> On 6/22/2015 10:10 AM, Ray Rankins wrote:
> > Thanks Matt,
> > I might expect some slight performance degradation compared to Sybase
> bcp (or SQL Server bcp), but I'm seeing orders of magnitude degradation (1.5
> minutes versus 1.5 hours for 5 million rows).
> > The table is pretty simple - no large object types.
> > Mostly int and float fields. Largest char field is 7 characters.
> > There is one non-nulllable date field at the end which has a default -
> freebcp didn't like that the file didn't contain a value for the last field, but I
> worked around this using a format file or by making the last field nullable.
> > CREATE TABLE [dbo].[test_table](
> > [val_geo] [char](5) NOT NULL,
> > [cd_wrsi_mdl] [smallint] NOT NULL,
> > [cd_geo_srce] [int] NOT NULL,
> > [cd_ppty_type_cpr] [char](1) NOT NULL,
> > [cd_mrtg_purp_altv] [char](4) NOT NULL,
> > [text_grth_multr_mol] [char](7) NOT NULL,
> > [cd_geo_type] [smallint] NULL,
> > [rate_grth_multr] [float] NULL,
> > [rate_std_dev_neg] [float] NULL,
> > [rate_std_dev_pstv] [float] NULL,
> > [dt_lst_updt] [date] default getdate()NULL
> > )
> > Initially, I was running freebcp from a Solaris host to SQL Server on
> Windows, but then I tested Sybase bcp and freebcp both running on the
> same Solaris client and importing into the same ASE server running on a Linux
> host, so it was an apples to apples comparison between the 2.
> > The import file is a text file, so the flags I'm using are -c, -t, -r with the -b to
> set a batch size of 10000
> > Also tried -f with a format file and there was no noticeable performance
> difference (although there did appear to be a bug when using the format file
> where seemed to ignore the -b option).
> > I don't have much access to the Sybase server to do too much monitoring,
> but what I could see, it seemed like it was waiting on network I/O most of
> the time.
> > Is there and easy way to tell of the BCP is using fast bcp versus fully logged
> besides looking at what's being written to the log file?
> > -Ray
> >> -----Original Message-----
> >> From: FreeTDS [mailto:freetds-bounces at lists.ibiblio.org] On Behalf Of
> >> Matthew
> >> Sent: Saturday, June 20, 2015 9:40 AM
> >> To: FreeTDS Development Group
> >> Subject: Re: [freetds] 0.91 freebcp performance
> >> Hi Ray,
> >> I did come across performance problems when compared to Sybase bcp
> >> those were mostly around text and image data types. Those problems
> >> appeared to be fixed, in my testing, or at least greatly improved when I
> >> tried a nightly from a few weeks ago.
> >> What's the definition of the table you are using and which flags are you
> >> using? Can you take a look inside the Sybase server and see what it's
> >> waiting for when you use freetds and which packet size the connection is
> >> using? I assume your comparison is from the same machine and it's not
> >> the case that you're running the Sybase bcp locally and freetds
> >> remotely? Can you see if both are using fast bcp, i.e. minimally logged
> >> or are both using fully logged?
> >> Just some ideas unless someone else has got better ones!
> >> Cheers,
> >> Matthew
> >> On 20/06/15 15:18, Ray Rankins wrote:
> >>> Just tested running a large bcp with 0.91 freebcp and the performance
> >> awful.
> >>> Took 1.5 hours to load 5 million rows (conversely, Sybase bcp loaded the
> >> same file in 1.5 minutes).
> >>> Is there some setting that might be on during compile that would cause
> >> freebcp to run slow.
> >>> I checked and double checked that the debug flags were not enabled
> >> made that mistake before) and they were not.
> >>> Are there any compile time options that could slow down freebcp that I
> >> should make sure are disabled when I compile it?
> >>> -Ray
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