-----Original Message-----
From: Andy Colson [mailto:andy@xxxxxxxxxxxxxxx]
Sent: Wednesday, June 24, 2015 10:10 AM
To: Gauthier, Dave; Postgres General
Subject: Re: DB access speeds, App(linux)<->PG(linux) vs App(linux) <->MSSql(Windows)
On 6/24/2015 8:44 AM, Gauthier, Dave wrote:
Hi: I'm trying to get a 10,000 ft understanding of the difference in
DB access speeds for two different scenarios...
Scenario 1: Apps are on linux. PG DB is on linux (different server
than apps)
Scenario 2: Apps are on linux. MSSql DB is on Windows (obviously a
different server)
The apps are typically perl scripts using Perl DBI.
I'm thinking that since perl has a DBD driver for PG, that would be
faster than going through ODBC to get to the MsSQL DB, but I'm not
sure about that.
Any insights/guesses ?
Thanks in Advance.
I think it'll depend on your usage.
If you fire off one really big analytic sql that chews on a huge table and does stats and counts, then odbc vs native will make no difference.
If you fire off lots and lots of small querys that hit an index and return very fast, then native is the way to go.
-Andy
On 6/24/2015 10:13 AM, Gauthier, Dave wrote:>
>>> 1) The same schema, data on both DB servers?
> Yes, identical
>>> 2) Are they the same apps?
> Yes, the same. The only diff is the db connect.
>>> 3) What are the apps doing?
> The vast, vast majority are small queries, often run inside large
programming loops.
>
>>> If you fire off lots and lots of small querys that hit an index and
return very fast, then native is the way to go.
> By this are you implying that there is more overhead using ODBC vs
Perl DBI-DBD ? If so, any guess, percentage wise, of how much slower
it would be? 50% slower? 2x? Other?
>
> Some (who really don't understand DB mechanics, or even know what
odbc is) are telling me that there is no difference. I say there is,
but this is an intuitive response. I'm trying to tap more experienced
people for something more solid.
>
>
>
>
I am totally guessing! I have never benchmarked odbc vs native.
But you have bigger problems. You have win vs linux, pg vs mssql, odbc
vs native to contend with.
Benchmarking a bunch of queries to one vs the other wont tell you which
(os, db, method) is the slow part.
To only measure odbc vs native you'd need everything else to be the same.
I'd recommend benchmarking you app to each db and just see which is
faster. You wont know why its faster but do you really care?
-Andy
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