Re: Our naming of wait events is a disaster.

For the specific category of the heavyweight lock types, I'm
now thinking that we can't change the event names very much, because
those are also exposed in pg_locks' locktype column. We can be
darn certain, for example, that changing the spelling of "relation"
in that column would break a lot of user queries. Conceivably we
could decouple the wait event names from the locktype column, but
on the whole that doesn't seem like a great plan.

However, having said that, I remain on the warpath about "speculative
token". That's an utterly horrid choice for both locktype and wait
event. I also notice, with no amusement, that "speculative token"
is not documented in the pg_locks documentation. So I think we should
change it ... but to what, exactly? Looking at the other existing names:

const char *const LockTagTypeNames[] = {
"relation",
"extend",
"page",
"tuple",
"transactionid",
"virtualxid",
"speculative token",
"object",
"userlock",
"advisory"
};

I'm inclined to propose "spectoken". I'd be okay with "spec_token" as
well, but there are not underscores in the longer-established names.

(Needless to say, this array is going to gain a comment noting that
there are two places to document any changes. Also, if we split up
the wait_event table as discussed earlier, it might make sense for
pg_locks' documentation to cross-reference the sub-table for heavyweight
lock events, since that has some explanation of what the codes mean.)

regards, tom lane