pgbench results arent accurate

2018-12-12 Thread Mariel Cherkassky
Hey,
I installed a new postgres 9.6 on both of my machines. I'm trying to
measure the differences between the performances in each machine but it
seems that the results arent accurate.
I did 2 tests :

1)In the first test the scale was set to 100 :
pgbench -i -s 100 -U postgres -d bench -h machine_name
pgbench -U postgres -d bench  -h machine_name -j 2 -c 16 -T 300
RUNTPS - machine1 TPS-machine2
1 697 555
2 732 861
3 784 842


2)In this test the scale was set to 1 :
pgbench -i -s 1 -U postgres -d bench -h machine_name
pgbench -U postgres -d bench --progress=30 -h machine_name -j 2 -c 16 -T
300
RUN TPS-MACHINE1  TPS-MACHINE2
1 103 60
2 63 66
3 74 83
4 56 61
5 75 53
6 73 60
7 62 53

In both cases after the initalization I restarted the database and cleared
the cashe(echo 1 > /proc/sys/vm/drop_caches) one time. During all the runs
I didnt shutdown the machine.

Now, I was hopping the the tps will be almost the same in each machine for
all the runs. In other words, I wanted to see that the tps in machine1
during all the tps are almost the same but I see that the values arent
accurate.

Any idea what might cause the differences in every run ?


Re: PostgreSQL VS MongoDB: a use case comparison

2018-12-12 Thread Nicolas Paris
On Tue, Nov 20, 2018 at 08:34:20AM -0500, Stephen Frost wrote:
> > Anyway, to bring data from JSON to a relational model is out of topic
> > for the current discussion, since we are actually questioning if
> > Postgres is a good replacement for Mongo when handling JSON data.
> 
> This narrow viewpoint isn't really sensible though- what you should be
> thinking about is what's appropriate for your *data*.  JSON is just a
> data format, and while it's alright as a system inter-exchange format,
> it's rather terrible as a storage format.

I would add that *FHIR* is an inter-exchange format instead of a storage
format. FHIR spec evolves and its json format too. When implemented in
a relational format it allows to only change the serialization process
(eg: json_tuple & co) instead of the data. In case FHIR is stored as a
json, it makes the information frozen in its version and complicate to
make evolve.


-- 
nicolas