Re: POC, WIP: OR-clause support for indexes - Mailing list pgsql-hackers

Hi, all! Sorry I haven't written for a long time.

I finished writing the code patch for transformation "Or" expressions to "Any" expressions. I didn't see any problems in regression tests, even when I changed the constant at which the minimum or expression is replaced by any at 0. I ran my patch on sqlancer and so far the code has never fallen.

I agree with your idea and try to implement it and will soon attach a patch with a solution.

Additionally, if those OR constants repeat you'll see ...

If all constants are the same value, fine

explain select * from x where ((ID = 1) OR (ID = 1) OR (ID = 1)); 

Index Only Scan using x_id on x  (cost=0.42..4.44 rows=1 width=4)
  Index Cond: (id = 1)

if all values are almost the same, ops

explain select * from x where ((ID = 1) OR (ID = 1) OR (ID = 1) OR (ID = 2));

Bitmap Heap Scan on x  (cost=17.73..33.45 rows=4 width=4)
  Recheck Cond: ((id = 1) OR (id = 1) OR (id = 1) OR (id = 2))
  ->  BitmapOr  (cost=17.73..17.73 rows=4 width=0)
        ->  Bitmap Index Scan on x_id  (cost=0.00..4.43 rows=1 width=0)
              Index Cond: (id = 1)
        ->  Bitmap Index Scan on x_id  (cost=0.00..4.43 rows=1 width=0)
              Index Cond: (id = 1)
        ->  Bitmap Index Scan on x_id  (cost=0.00..4.43 rows=1 width=0)
              Index Cond: (id = 1)
        ->  Bitmap Index Scan on x_id  (cost=0.00..4.43 rows=1 width=0)
              Index Cond: (id = 2)

thanks

Marcos

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Regards,

Alena Rybakina