Neil Conway <neilc@samurai.com> writes:
> (BTW, is poor concurrency really the biggest issue with hash indexes? If
> so, there is some low-hanging fruit that I noticed a few years ago, but
> never got around to fixing: _hash_doinsert() write-locks the hash
> metapage on every insertion merely to increment a tuple counter.
Given the short amount of time that lock is held, this wouldn't
win anything worth noticing. Also, it's not "merely" to increment a
counter --- the counter drives decisions about whether to split buckets,
so any decrease in accuracy would lead directly to losses in overall
performance.
The lack of WAL support is a much bigger issue.
regards, tom lane