Обсуждение: a couple of newbie question - deferrable, varchar vs text, 2 dbs

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a couple of newbie question - deferrable, varchar vs text, 2 dbs

От
"Sergei Shelukhin"
Дата:
1) Do I understand it correctly that cross database queries are not
possible? Two dbs on the same server are used in this case.

2) What's the difference between unlimited length varchar and text
columns? I am mostly interested in performance, namely = 'blah' and
like '%blah%' queries over these column types.

3) Will adding "deferrable" to FKs that reference very large tables
speed up insert performance for individual inserts? for multiple
inserts within a single transaction?

Thanks ;)


Re: a couple of newbie question - deferrable, varchar vs text, 2 dbs

От
Peter Eisentraut
Дата:
Sergei Shelukhin wrote:
> 1) Do I understand it correctly that cross database queries are not
> possible?

Yes.

> 2) What's the difference between unlimited length varchar and text
> columns?

Mostly only the spelling.

> 3) Will adding "deferrable" to FKs that reference very large tables
> speed up insert performance for individual inserts? for multiple
> inserts within a single transaction?

I think you can answer that yourself with a quick test.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

Re: a couple of newbie question - deferrable, varchar vs text, 2 dbs

От
"Sergei Shelukhin"
Дата:
Thanks :)
As for pt3, I don't have the database I will use yet so it's hard to
test :(