I wanted to update a record if it existed, otherwise use insert. So if a name is in the database, update the times I've seen it. If the name does not exist, insert. I was keeping track of the number of times a name is seen.
Without knowing much about your actual application (i.e. treat the following with utmost skepticism!), my instinct would be to separate the fact of observing a name from the fact of the observation count. I would keep a log table and a summary table like this:
CREATE TABLE namelog (
name TEXT
);
CREATE TABLE namesummary (
name TEXT,
seen int
);
Then each time you see a name, log it:
INSERT INTO namelog VALUES (%s)
Then on a regular basis, run a housekeeping/summary process like this:
CREATE TEMPORARY TABLE prevsummary AS
SELECT * FROM namesummary;
TRUNCATE namesummary;
INSERT INTO namesummary
SELECT coalesce(a.name, b.name) as name,
coalesce(a.seen,0) + coalesce(b.seen, 0) as seen
FROM
prevsummary a
FULL OUTER JOIN
(SELECT name, count(*) as seen
FROM namelog
GROUP BY name) b
ON a.name=b.name
;
DELETE FROM namelog;
This of course is grossly space-inefficient, but making the logging process INSERT-only should enable a great degree of concurrency - and you can tune the summary process to run as often as necessary to keep memory/disk usage within your available resources.
If concurrency isn't an issue, then your initial solution is probably fine.
Very nice approach, I didn't think of trying to log names with only INSERT. I see how it handles concurrency. My solution is likely to fail if my database gets bombarded...My app was supposed to be a simple one I made for a few friends and also for me to learn a few things in node / postgres.
For more detail, here is my initial table:
CREATE TABLE names(name_id serial, name text, count integer)
I was planning to access the name count a good numbers of times, so I went with a simple SELECT from names. I don't necessarily need "on demand" counts so having the summary process run 5 or 10 mins would be a better!