Dmitry Koterov dmi...@koterov.ru writes:
No, I meant that in case of the row (1, NULL, NULL, 2, 3, NULL):
- the corresponding NULL bitmap is (100110...)
- the corresponding tuple is (1, 2, 3)
- t_natts=3 (if I am not wrong here)
You are wrong --- t_natts would be six here. In general
Dmitry Koterov dmi...@koterov.ru writes:
No, I meant that in case of the row (1, NULL, NULL, 2, 3, NULL):
- the corresponding NULL bitmap is (100110...)
- the corresponding tuple is (1, 2, 3)
- t_natts=3 (if I am not wrong here)
You are wrong --- t_natts would be six here. In general the
On Thu, May 21, 2009 at 12:26:08PM -0400, Tom Lane wrote:
I'd envision it
as an extra column in pg_attribute, and it would work for any column(s).
There's nothing to be gained by restricting it.
Yes, when I said first I meant the only thing that needs to be stored
is the first default value
On Thu, May 21, 2009 at 6:45 PM, Tom Lane t...@sss.pgh.pa.us wrote:
Sam Mason s...@samason.me.uk writes:
On Thu, May 21, 2009 at 12:06:29PM +0400, Dmitry Koterov wrote:
ALTER TABLE ... ADD COLUMN ... NULL;
(nullable without a default value). This is because of NULL bitmap in
tuples.
Hello.
PostgreSQL is very fast when we perform (even on a huge table)
ALTER TABLE ... ADD COLUMN ... NULL;
(nullable without a default value). This is because of NULL bitmap in
tuples. And it's greatest feature for a developer!
But another very common-case query like
ALTER TABLE ... ADD
On Thursday 21 May 2009 11:06:29 Dmitry Koterov wrote:
1. Store the DEFAULT flag directly in NULL BITMAP (add a bit to NULL bitmap
not only for NULLable fields, but also for NOT NULL DEFAULT ... fields).
2. Add another bitmap for each tuple (DEFAULT bitmap). Bit value 0 means
that there is a
On Thu, May 21, 2009 at 12:06:29PM +0400, Dmitry Koterov wrote:
ALTER TABLE ... ADD COLUMN ... NULL;
(nullable without a default value). This is because of NULL bitmap in
tuples. And it's greatest feature for a developer!
I don't think this is because of the NULL bitmap. PG just never needs
(In most cases NOT NULL DEFAULT xxx fields are BOOLEAN, flags: it is not
handy to have 3-way flags.)
This is certainly not true for me. I have both nullable booleans and
not-nullable, defaulted columns of other types.
So, are there plans to optimize such kind of queries? This could be done
Sam Mason s...@samason.me.uk writes:
On Thu, May 21, 2009 at 12:06:29PM +0400, Dmitry Koterov wrote:
ALTER TABLE ... ADD COLUMN ... NULL;
(nullable without a default value). This is because of NULL bitmap in
tuples. And it's greatest feature for a developer!
I don't think this is because
On Thu, May 21, 2009 at 10:45 AM, Tom Lane t...@sss.pgh.pa.us wrote:
Sam Mason s...@samason.me.uk writes:
On Thu, May 21, 2009 at 12:06:29PM +0400, Dmitry Koterov wrote:
ALTER TABLE ... ADD COLUMN ... NULL;
(nullable without a default value). This is because of NULL bitmap in
tuples. And
On Thu, May 21, 2009 at 3:45 PM, Tom Lane t...@sss.pgh.pa.us wrote:
All that needs to be tracked is the first default value (this is
currently assumed to be NULL).
You're being a bit vague, but in any case I don't think it can work
for non-constant defaults (consider DEFAULT NOW()). And
Greg Stark st...@enterprisedb.com writes:
Schemes like this have been discussed before but I don't think we
considered applying the limitation that only the first default value
would be covered. We always wanted to be able to handle new defaults
or making a non-null column nullable later.
On Thu, May 21, 2009 at 11:13 AM, Greg Stark st...@enterprisedb.com wrote:
On Thu, May 21, 2009 at 3:45 PM, Tom Lane t...@sss.pgh.pa.us wrote:
All that needs to be tracked is the first default value (this is
currently assumed to be NULL).
You're being a bit vague, but in any case I don't
On Thu, May 21, 2009 at 4:22 PM, Tom Lane t...@sss.pgh.pa.us wrote:
Greg Stark st...@enterprisedb.com writes:
Schemes like this have been discussed before but I don't think we
considered applying the limitation that only the first default value
would be covered. We always wanted to be able to
Greg Stark st...@enterprisedb.com writes:
On Thu, May 21, 2009 at 4:22 PM, Tom Lane t...@sss.pgh.pa.us wrote:
Yeah ... I don't see exactly what it would buy to restrict it to just
the first such value.
Well it wouldn't buy you steady-state space savings or performance
improvements.
What
--
Greg
On 21 May 2009, at 12:26, Tom Lane t...@sss.pgh.pa.us wrote:
Greg Stark st...@enterprisedb.com writes:
On Thu, May 21, 2009 at 4:22 PM, Tom Lane t...@sss.pgh.pa.us wrote:
Yeah ... I don't see exactly what it would buy to restrict it to
just
the first such value.
Well it
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