Garage, Glorp, PostgreSQL and Cursors

Hello,

I was trying the version of Glorp ported to Garage, and I must say it
runs smoothly, nice job!

I am reading large amount of data from a Postgres db, and I was curious
about the use of cursors.
I remember that the old version of Glorp for Pharo did not support
cursors in Postgresql, has this changed in Garage?

I tried to run some tests, using a query like:

(Query readManyOf: MyClass)
    collectionType: GlorpCursoredStream;
    yourself.

but with a large number of rows (~300k), the whole image crashes.

Is this still not supported, or am I doing something wrong?

Thanks,
Tommaso

03/08/15 16:10, Yuriy Mironenko [via Smalltalk] пишет:

I'm little bit shy, but what is Garage?

http://pharo.org/news/garage-database

2015-08-03 15:33 GMT+03:00 Tommaso Dal Sasso <[hidden email]>:

Hello,

I was trying the version of Glorp ported to Garage, and I must say it
runs smoothly, nice job!

I am reading large amount of data from a Postgres db, and I was curious
about the use of cursors.
I remember that the old version of Glorp for Pharo did not support
cursors in Postgresql, has this changed in Garage?

I tried to run some tests, using a query like:

(Query readManyOf: MyClass)
    collectionType: GlorpCursoredStream;
    yourself.

but with a large number of rows (~300k), the whole image crashes.

Is this still not supported, or am I doing something wrong?

Thanks,
Tommaso

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NAML

vmusulainen wrote

http://pharo.org/news/garage-database

I'm also confused. What is the relationship between OpenDBX and Garage? IIRC DBXTalk was the previous name of OpenDBX, right? Maybe an FAQ is in order as the DB-related names seem to be multiplying ;)

> On 03 Aug 2015, at 15:35, Sean P. DeNigris <[hidden email]> wrote:
>
> vmusulainen wrote
>> http://pharo.org/news/garage-database
>
> I'm also confused. What is the relationship between OpenDBX and Garage? IIRC
> DBXTalk was the previous name of OpenDBX, right? Maybe an FAQ is in order as
> the DB-related names seem to be multiplying ;)

not really.

DBXTalk is the suite that includes the OpenDBX driver (and others)
it also includes Garage, as a common layer for different database drivers, one of them OpenDBX

Esteban

Garage is a (IMO lousy named) Pharo database interface abstraction,
like Perl's DBI, ADODB, or JDBC.
Any program that uses Garage's objects to access the database should
be abstract enough to enable you to replace the backend by something
else without changing the programming logic (e.g. replace PostgreSQL
by SQLite).

DBXTalk is the same, but at the database driver level, it uses the
OpenDBX database drivers.

So the relation would be:
DB Interface -> DB Adapter -> DB Driver

With these possible combinations (among others):
Garage -> DBXTalk -> OpenDBX libs (libopendbx.so/dll)
Garage -> PostgreSQLv2 -> (written in Smalltalk)
Garage -> SQLite -> (written in Smalltalk)

The confusion comes also when you add GLORP (ORM) to the combo, which
is the most common use case when dealing with RDBMS, with the added
misnomer of GLORP calling "Driver" what in practice is an Adapter
(pattern) written in Smalltalk .

So you have the following
GlorpDriver (Adapter) -> DB Interface

So:
GlorpDBXTalk -> Garage
GlorpPostgresV2 -> PostgresV2
GlorpSQLite -> PunQLite


The benefits of having an abstraction layer like Garage are many,
maybe the misnomer and the lack of coordination provokes this
confusion.

Regards!

--
Esteban A. Maringolo


















Esteban A. Maringolo


2015-08-03 10:35 GMT-03:00 Sean P. DeNigris <[hidden email]>:

Esteban A. Maringolo wrote

Garage is...

Thank you! Very helpful. It seems like this would be a great clarification to add to http://guillep.github.io/DBXTalk/ , no?

yes… just that is not accurate :)
is basically like that, just that DBXTalk is not a driver, is an umbrella project. The OpenDBX drivers is still called OpenDBXDriver :P

Esteban

2015-08-03 16:20 GMT-03:00 Esteban Lorenzano <[hidden email]>:
> yes… just that is not accurate :)
> is basically like that, just that DBXTalk is not a driver, is an umbrella project. The OpenDBX drivers is still called OpenDBXDriver :P

TooManyAbstractionsException signal.

;)

Esteban A. Maringolo

On 04/08/15 16:25, Guillermo Polito wrote:
Hi Guillermo,

thanks, that would be really interesting.

Unfortunately right now I'm in a hurry to read some data from posgtgres,
so I'll manage to do that "by hand" (i.e. without cursors), but I think
that if we want to use Pharo for data analysis, being able to process
large volume of data in a lean way is a must (it is not the first time I
need it) and the option of glorp+cursors to stream the data from the db
without kill the ram would be amazing.

I would be happy to help enable this feature for Garage, but I don't
really know where to look, do you have any hints?

Tommaso