I found from where problem comes. It concerns duplicates,
not variable-length attribute (var(XXX) is fixed-length attr, Marc).
Reproduction under 6.1-current:
drop table bug_duplicate;
create table bug_duplicate (x int);
create index bug_duplicate_i on bug_duplicate (x);
copy bug_duplicate from '/home/postgres/My/Btree/BUG/I2';
- -- ^^
- -- 408 (!) records with x = 2
vacuum bug_duplicate;
select count(*) from bug_duplicate where x = 2;
count
- -----
408
(1 row)
insert into bug_duplicate values (1);
INSERT 1867199
select count(*) from bug_duplicate where x = 2;
count
- -----
203
(1 row)
=============
Under 6.0:
drop table bug_duplicate;
create table bug_duplicate (x int);
create index bug_duplicate_i on bug_duplicate (x);
copy bug_duplicate from '/tmp/I2';
- -- ^^
- -- 292 (!) records with x = 2
vacuum bug_duplicate;
select count(*) from bug_duplicate where x = 2;
count
- -----
292
(1
row)
insert into bug_duplicate values (1);
select count(*) from bug_duplicate where x = 2;
count
- -----
146
(1
row)
===============
This examples are not the same as
drop table bug_duplicate;
create table bug_duplicate (x int);
create index bug_duplicate_i on bug_duplicate (x);
copy bug_duplicate from '/home/postgres/My/Btree/BUG/I2';
- -- ^^
- -- = 450 records with x = 2
vacuum bug_duplicate;
And now:
vac=> select count(*) from bug_duplicate where x = 2;
count
- -----
450
(1 row)
vac=> insert into bug_duplicate values (1);
INSERT 1695826
vac=> select count(*) from bug_duplicate where x = 2;
count
- -----
204
(1 row)
: it's fixed currently - having 450 items with 2 splitting occures
before we inserts item with 1, - but in the new example
splitting occures when we insert item with 1.
=============
Ok. Found but unfixed, yet. I suggest to postpone release for
2-3 day and got to sleep.
Vadim
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