Re: questions about PG update performance

On 10/25/15 9:36 PM, Kisung Kim wrote:
> I want to explain for our clients that PG's update performance is
> comparable to Oracle's.

There's really only 2 ways you can answer that. You can either handwave 
the question away ("Yes, update performance is comparable."), or you 
have to do actual benchmarking. Trying to answer this from a theoretical 
standpoint is completely useless because there's an absurd number of 
things that will affect this:

Number of columns
Data types
Size of overall transaction
Percent of transactions that roll back
Size of table
What % of table is updated every day
Underlying hardware
What OS the database is running on
What filesystem the database is running on

... and that's just off the top of my head.

Or to look at it another way, I guarantee you can create a scenario 
where Postgres beats the pants off Oracle, *or vice versa*. So you have 
to either go with an answer along the lines of "For most workloads the 
performance of both databases is similar." or you have to benchmark the 
actual application in question. Most performance issues you find will 
probably be correctable with a moderate amount of work.

To me, the real tradeoff between Postgres and Oracle (or any other 
commercial database) is whether you'd rather spend money on expert 
employees or software contracts.
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com