Postgres DB performance issue

Question

I'm suspecting our Postgres DB has performance issue so I'm troubleshooting.

First I'm running a query below from my local laptop like below;

 "select * from table1"

And this table has 7 rows and it taks around 506 ms, seems slow.

So after then I run the query below;

 EXPLAIN ANALYZE select * from table1;

Output is below;

So if I'm correct, output says query took 0.008 second?

So how can I understand these values? Are these values ok?

Ps : Postgresql ver is 10.4 but I couldn't found the tag!

Thanks!

Those are 0.008 milliseconds. Do you get the same results if you repeat the experiment? What is the network latency between client and server? — Laurenz Albe
– Laurenz Albe, Commented Nov 25, 2021 at 8:40
pgAdmin is known to be quite slow when it comes to displaying results. This is not a Postgres performance problem, but a pgAdmin problem. — user330315
– user330315, Commented Nov 25, 2021 at 8:46
Is that a cloud instance? Maybe Azure PostgreSQL on Basic subscription? — Alex Yu
– Alex Yu, Commented Nov 25, 2021 at 8:58

Laurenz Albe · Accepted Answer · 2021-11-25 09:29:59Z

2

The difference must be network lag.

You could try with a query that does nothing really and see if you get a similar duration:

SELECT 1;

That should show the same duration and would confirm that there is a network latency of around 250 ms.

answered Nov 25, 2021 at 9:29

Laurenz Albe

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4 Comments

yatta Over a year ago

Yes, it took around 250 ms, so basically that time means "query time+ the time to get data to the laptop(pgadmin)" ? Do you know what is the exact query time then? 0.008 ms or (planning time+execution time)?

Laurenz Albe Over a year ago

The query took 0.076 milliseconds (planning + execution), the sequential scan 0.008 milliseconds.

yatta Over a year ago

To make it clear, that ~250ms, which I saw on Pgadmin after running a query means that "query time+ the time to get data to the laptop(pgadmin)"?

Laurenz Albe Over a year ago

That's the time the client measures between sending the client to the server and receiving an answer.

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