Tom Lane <t...@sss.pgh.pa.us> wrote: > Takahiro Itagaki <itagaki.takah...@oss.ntt.co.jp> writes: > > Instead, how about excluding columns in primary keys from table data? > > How will you implement "select * from mytable" ? Or even > "select * from mytable where non_primary_key = something" ?
Use index full scans. We can do it even for now with enable_seqscan = off. Of course, it requires an additional step to merge index keys and heap tuples. Also, we're using the same technique for TOASTed values. The cost can be compared with "select * from mytable where toasted_value = something", no? > If you can't do either of those without great expense, I think > a savings on primary-key lookups is not going to be adequate > recompense. I don't think it will be the default, but it would be a reasonable trade-off for users who want IOTs, unless they often scan the whole table. Regards, --- Takahiro Itagaki NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
