52 lines
1.5 KiB
MySQL
52 lines
1.5 KiB
MySQL
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-- Prior to this, the count endpoint was super naive and just ran COUNT(1).
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-- This is slow asf. Now that we have an amount of actual traffic,
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-- stop doing that!
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-- This basically maintains a count, so we can read ONE row, instead of ALL the
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-- rows. Much better.
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-- Future optimisation could use some sort of cache so we don't even need to hit
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-- postgres at all.
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create table total_history_count_user(
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id bigserial primary key,
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user_id bigserial,
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total integer -- try and avoid using keywords - hence total, not count
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);
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create or replace function user_history_count()
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returns trigger as
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$func$
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begin
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if (TG_OP='INSERT') then
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update total_history_count_user set total = total + 1 where user_id = new.user_id;
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if not found then
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insert into total_history_count_user(user_id, total)
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values (
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new.user_id,
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(select count(1) from history where user_id = new.user_id)
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);
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end if;
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elsif (TG_OP='DELETE') then
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update total_history_count_user set total = total - 1 where user_id = new.user_id;
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if not found then
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insert into total_history_count_user(user_id, total)
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values (
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new.user_id,
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(select count(1) from history where user_id = new.user_id)
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);
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end if;
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end if;
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return NEW; -- this is actually ignored for an after trigger, but oh well
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end;
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$func$
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language plpgsql volatile -- pldfplplpflh
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cost 100; -- default value
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create trigger tg_user_history_count
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after insert or delete on history
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for each row
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execute procedure user_history_count();
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