>> I just dug out the PostgreSQL book again because I thought I might've >> garbled it: >> >> Quote: "PostgreSQL will not index NULL values. Because an index will >> never include NULL values, it cannot be used to satisfy the ORDER BY >> clause of a query that returns all rows in a table." > > You should just cross out that whole section. It's just flatly wrong. > > I had always assumed it was just people bringing assumptions over from > Oracle where it is true. Perhaps this book is to blame for some of the > confusion. Which book is it? > > Postgres indexes NULLs. It can use them for ORDER BY clauses.
Now I'm confused... here's a quote from Bruce Momjian from Oct. 2003: > To be specific, we do not do index NULL values in a column, but we > easily index non-null values in the column. And a comment from backend/access/gist/gist.c (appears a few times): > GiST cannot index tuples with leading NULLs So what's the story? Do GiST indexes index NULLs? Do other index types index NULLs? Is the comment wrong or am I misreading it? ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org