overhead – select * from depesz;

What is index overhead on writes?

One of things people learn is that adding indexes isn't free. All write operations (insert, update, delete) will be slower – well, they have to update index.

But realistically – how much slower?

Full tests should involve lots of operations, on realistic data, but I just wanted to see some basic info. So I figured I'll just look at speed of inserting data (well, COPYing data), and will try to extract some knowledge from it…

Continue reading What is index overhead on writes?

Waiting for 9.2 – EXPLAIN TIMING

On 7th of February, Robert Haas committed patch:

Sometimes it may be useful to get actual row counts out of EXPLAIN
(ANALYZE) without paying the cost of timing every node entry/exit.
With this patch, you can say EXPLAIN (ANALYZE, TIMING OFF) to get that.
 
Tomas Vondra, reviewed by Eric Theise, with minor doc changes by me.

Continue reading Waiting for 9.2 – EXPLAIN TIMING

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Tag: overhead

What is index overhead on writes?

Waiting for 9.2 – EXPLAIN TIMING