"Bruce Momjian" <[EMAIL PROTECTED]> writes: >> No, we did substring() too :) > > Uh, I looked at text_substring(), and while there is an optimization to > do character counting for encoding length == 1, it is still accessing > the data.
Sure but it'll only access the first chunk. There are two chunks in your test. It might be interesting to run tests accessing 0 (length()), 1 (substr()), and 2 chunks (hashtext()). Or if you're concerned with the cpu cost of hashtext you could calculate the precise two bytes you need to access with substr to force it to load both chunks. But I think the real cost of unnecessary toasting is the random disk i/o so the cpu cost is of secondary interest. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly