On Wed, May 31, 2017 at 6:53 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Alexander Korotkov <a.korot...@postgrespro.ru> writes: > > I've discovered that PostgreSQL is able to run following kind of queries > in > > order to change statistic-gathering target for an indexed expression. > > > ALTER INDEX index_name ALTER COLUMN expr SET STATISTICS stat_target; > > > It's been previously discussed in [1]. > > > I think this should be fixed not just in docs. This is why I've started > > thread in pgsql-hackers. For me usage of internal column names "expr", > > "expr1", "expr2" etc. looks weird. And I think we should replace it > with a > > better syntax. What do you think about these options? > > > ALTER INDEX index_name ALTER EXPRESSION 0 SET STATISTICS stat_target; -- > > Refer expression by its number > > ALTER INDEX index_name ALTER EXPRESSION (x + y) SET STATISTICS > stat_target; > > -- Refer expression by its definition > > Don't like either of those particularly, but what about just targeting > a column by column number, independently of whether it's an expression? > > ALTER INDEX myindex ALTER COLUMN 4 SET STATISTICS 1000; > I completely agree with that. If no objections, I will write a patch for that. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
