Bruce Momjian wrote: > Alvaro Herrera wrote: > >> Karl Denninger escribi?: >> >> >>> The individual boolean fields don't kill me and in terms of some of the >>> application issues they're actually rather easy to code for. >>> >>> The problem with re-coding for them is extensibility (by those who >>> install and administer the package); a mask leaves open lots of extra >>> bits for "site-specific" use, where hard-coding booleans does not, and >>> since the executable is a binary it instantly becomes a huge problem for >>> everyone but me. >>> >> Did you try hiding the bitmask operations inside a function as Tom >> suggested? >> > > Yes. In addition, functions that are part of expression indexes do get > their own optimizer statistics, so it does allow you to get optimizer > stats for your test without having to use booleans. > > I see this documented in the 8.0 release notes: > > * "ANALYZE" now collects statistics for expression indexes (Tom) > Expression indexes (also called functional indexes) allow users > to index not just columns but the results of expressions and > function calls. With this release, the optimizer can gather and > use statistics about the contents of expression indexes. This will > greatly improve the quality of planning for queries in which an > expression index is relevant. > > Is this in our main documentation somewhere? > > Interesting... declaring this:
create function ispermitted(text, integer) returns boolean as $$ select permission & $2 = permission from forum where forum.name=$1; $$ Language SQL STABLE; then calling it with "ispermitted(post.forum, '4')" as one of the terms causes the query optimizer to treat it as a FILTER instead of a nested loop, and it works as expected. However, I don't think I can index that - right - since there are two variables involved which are not part of the table being indexed..... -- Karl
<<attachment: karl.vcf>>
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