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

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

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#i2698625>*
* 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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