Also i'd like to answer you if postgresQL has implemented rcursive queries
proposed from SQL99 standard?
If yes, are there any restrictions of the model on your implementation?
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TIP 2: you can get off all lists at once wit
Hi,
in case one use 'inherits' relationship to create a hierarchy of
tables, table 'pg_inherits' stores for each table the information of which
is its parent table.
During the evaluation of a query like
select * from Root;
where Root is the 'root' table of our hierarchy, postgreSQL needs to
fi
Hi, i found this form of output of explain analyze, watching some old
mails in lists.
test4=# explain analyze select * from patients;
LOG: query: explain analyze select * from patients;
LOG: duration: 0.603887 sec
LOG: QUERY STATISTICS
! system usage stats:
! 0.624269 elapsed 0.458985 u
> >
> > Is there any compression or what?
>
> Yes, there is:
>
> http://www.postgresql.org/docs/8.0/interactive/storage-toast.html
thanks, is there any way to increase the limit, upper wich toast strategy
is selected? By defaullt is Block_size/4 = about 2000 Bytes.
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>
> varchar means 'character varying'. What varies is the length. So a
> varchar(1000) with 'foo' in it only takes a few bytes ('foo' plus length
> info) instead of 1000 bytes.
Yes i know it, but i have vorgotten to inform you that all the values of
this attribute have really 1000 characthers le
Hi,
i have a table:
create table triples(
att0 varchar(1000),
att1 int4,
att2 varchar(20),
att3 varchar(1000)
)
My table has 990 raws.
The (possibly wrong) way, with wich i compute the size of the table is:
att0: 1000 * 1 Byte + 4 = 1004 Bytes
att2: 20 * 1 Byte
let me, i have turned enable_seqscan to off, in order to discourage
optimizer to choose seq_scan whenever an idex_scan can be used.
But in this case, why optimizer don't chooses seq_scan (discourage is
different than prevent) ?
At many cases i need only a small fragment of raws to be retrieved.
> If there are many identical values in att0, are you sure a sequential
> scan isn't more efficient? Also, are you sure the index isn't working
> well? It seems to me since you have the table clustered, it might be
> fairly efficient as-is (it would get a huge benefit from the spatial
> locality o
Please let me know, if there is any option in postgresql to achieve the
following usage of a b-tree index:
For a relation R(att0, att1) and a btree index on attribute att0
In each insertion of a tuple on table:
- look on index if the value of att0 of new entry does already exist in
index, and
