4 ms·
Very true. Also, along those lines, if you have fewer than 10k rows, it’s likely the dB will keep the whole table in memory after the first access, anyway.
by pfarrell 6y ago
Very true. Also, along those lines, if you have fewer than 10k rows, it’s likely the dB will keep the whole table in memory after the first access, anyway.
- jimsmart 6y agoIn an ideal situation, agreed. But surely that depends entirely on how many tables are being queried (how many tables already exist in the cache), the size of the rows, how much RAM the host has / how big the cache is, plus a few other variables most probably. What I mean is: like all other things, it depends. And with assumptions like this, it is generally better to measure.
- skeeter2020 6y agohe's not really talking about the performance of the DB though, focusing more on size of the resultant payload thatr gets sent over the wire. In the actual database which is traditionally very challenging to scale, projections aren't very expensive. The other things you and GP mention are way more likkely to move the performance needle.