Re: [cx-oracle-users] Arraysize dependent on run time?

[Moritz L. <mor...@go...>]

No I was wrong the Oracle docu *SET ARRAY[SIZE] {15 | n}
<https://docs.oracle.com/cd/B28359_01/server.111/b31189/ch12040.htm#i2698625>
*is
regarding to sql* Plus and is not refering to python.
So it doesn´t matter in my case. But I have some problems with the aslist()
method for objects.

*My case:*
1.) If I only execute the query (cursor.execute(sql) and print the result
the browser needs around 0,8s
2.) If I do the for-loop this way I need 0,2 seconds:

for id, geometry, classname in cursor:
            result.append({"building_nr":id,"geometry":{"type":"
polygon","coordinates":geometry,},"polygon_typ":classname,})
retunr result


3.) But If I create a List and iterate over this list I need 11 seconds!!!:
for id, geometry, classname in cursor:
            mo = geometry.SDO_ORDINATES.aslist()
            result.append({"building_nr":id,"geometry":{"type":"
polygon","coordinates":zip(*[iter(mo)] * ,},"polygon_typ":classname,})

return json.dumps(result)

But sadly I need the coordinates. Is there a workaround for object.aslist()
?

2016-08-28 22:04 GMT+02:00 Shai Berger <sh...@pl...>:

> Then, perhaps you can just avoid doing that?
>
> If I get it right, the ArraySize does not limit the size of overall
> returned
> results, but only the size returned to the client in one batch.
>
> Add to this that, according to the documentation you linked and quoted
> yourself, 6,000 is not a valid value...
>
> Why don't you just try leaving that value alone?
>
> On Thursday 25 August 2016 12:59:07 Moritz Liebelt wrote:
> > Hi Shai,
> >
> > I did a test query in sql Developer and it seems that Oracle is not
> > responsible for that.
> >
> > But to fetch all the rows from my Database I have to increase the
> arraysize
> > in cx_Oracle (*cursor.arraysize* default=50, my setting = 6.000)
> > Furthermore it is written in the Oracle Docu
> >
> > *SET ARRAY[SIZE] {15 | n}
> > <https://docs.oracle.com/cd/B28359_01/server.111/b31189/
> ch12040.htm#i269862
> > 5>* * Sets the number of rows, called a batch, that SQL*Plus will fetch
> > from the database at one time.Valid values are 1 to 5000. A large value
> > increases the efficiency of queries and subqueries that fetch many rows,
> > but requires more memory.*
> >
> > And In my case under 5000 rows it neeeds some milliseconds and over 5000
> > rows it needs some seconds. So is this depending on the arraysize?
> >
> > 2016-08-23 21:42 GMT+02:00 Shai Berger <sh...@pl...>:
> > > Hi Moritz,
> > >
> > > Two notions come to mind:
> > >
> > > 1) Are you sure the time is wasted in Python-land? Do you have a way to
> > > measure the execution of the query without Python or cx_Oracle being
> > > invoved
> > > (e.g. in SQL*Plus)?
> > >
> > > 2) Assuming it is -- I've seen delays on the order of seconds show up
> > > when you
> > > create a lot of circular references -- the Python GC gets invoked then
> > > and can
> > > cause surprisingly large "lapses". You can check the documentation of
> the
> > > stdlib's gc module for ways to verify and/or eliminate this issue.
> > >
> > > HTH,
> > >
> > >         Shai.
> > >
> > > On Tuesday 23 August 2016 18:43:26 Moritz Liebelt wrote:
> > > > Hi,
> > > >
> > > > I fetch rows form an Oracle Locator DB with web.py and cx_Oracle! I
> use
> > >
> > > the
> > >
> > > > unreleased version of cx_Oracle! Furthermore I read the sdo_geometry
> > > > objects in the sql-statement and build a json based on this.
> > > >
> > > > For a 500m-Tile with 4634 rows I need 0,326 (measured time in the
> > >
> > > browser=
> > >
> > > > waiting time (DB + Webserver))
> > > > For a 500m-Tile with 5081 rows I need 10,1 second???
> > > > You can see an overview
> > > >
> > > >   *500m-Tile_A ( 2311 rows)* *500m-Tile_B (3799 rows)* *400m-Tile
> (4137
> > > >
> > > > rows)* *500m-Tile_E (4634 rows)* *500m-Tile_C (5081 rows)* *500m-Tile
> > > > _D (6241 rows)*
> > > > *sdo_geometry (cx_Oracle)* 0,18s 0,26s 0,27s 0,326s 10,1s 13,77s
> > > > *Size* 729KB 1,2 MB 1,3 MB 1,4MB 1,6 MB 2 MB
> > > >
> > > > Is there anywhere a Threshold? Because the time is increasing and I
> do
> > >
> > > not
> > >
> > > > understand why.
> > > > It does not refer to Browser problems. I think that this is depending
> > > > on the webserver.
> > > >
> > > > Does someone knows this issue?
> > >
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-- 
*Moritz Liebelt, B. Sc.*

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76437 Rastatt
E-Mail: mor...@go...