Thread: Documentation mistake?

Documentation mistake?

From
PG Doc comments form
Date:
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/17/indexes-bitmap-scans.html
Description:

In page https://www.postgresql.org/docs/current/indexes-bitmap-scans.html
написано следующее:
"Another example is that if we have separate indexes on x and y, one
possible implementation of a query like WHERE x = 5 AND y = 6 is to use each
index with the appropriate query clause and then AND together the index
results to identify the result rows".
You mean "WHERE x = 5 OR y = 6"?
result from index scan by x + result from index scan by y 
Thx.

Re: Documentation mistake?

From
"David G. Johnston"
Date:
On Thursday, October 24, 2024, PG Doc comments form <noreply@postgresql.org> wrote:
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/17/indexes-bitmap-scans.html
Description:

In page https://www.postgresql.org/docs/current/indexes-bitmap-scans.html
написано следующее:
"Another example is that if we have separate indexes on x and y, one
possible implementation of a query like WHERE x = 5 AND y = 6 is to use each
index with the appropriate query clause and then AND together the index
results to identify the result rows".


This is a correct and intended sentence.  The paragraph for bitmap covers both OR from the earlier example and AND from this example.

David J.
 

Re: Documentation mistake?

From
Tom Lane
Date:
PG Doc comments form <noreply@postgresql.org> writes:
> In page https://www.postgresql.org/docs/current/indexes-bitmap-scans.html
> написано следующее:
> "Another example is that if we have separate indexes on x and y, one
> possible implementation of a query like WHERE x = 5 AND y = 6 is to use each
> index with the appropriate query clause and then AND together the index
> results to identify the result rows".

> You mean "WHERE x = 5 OR y = 6"?

No; the query says AND.  Unioning the index results would be
appropriate if it said OR, but that's a different topic.

            regards, tom lane