Hi,
1.5b rows is rather big data.
Could you test what .values() or .values_list() produces in terms of speed.
also print qs might actually pull in all selected records in Python memory so
it may take a while to constuct bunch of objects.
On Thu, 22 Jan 2015 07:32:36 -0800 (PST)
Joris Benschop <joris.bensc...@gmail.com> wrote:
> Dear List,
>
> I'm trying to run a simple select on a very large Oracle table (1500
> million records).
>
> I create a standard django model:
> ------------------
> class Marker(models.Model):
> marker_id = SYSGUID16Field(primary_key=True) # This field type is a
> guess.
> markid = models.CharField(unique=True, max_length=20, blank=True)
> crop = models.ForeignKey("variantdb_admin.Crop", blank=True, null=True)
> insid = models.CharField(max_length=5, blank=True)
> insdate = models.DateTimeField(blank=True, null=True)
>
> class Meta:
> managed = False
> db_table = "prod_schema"."marker"
> ------------------
>
> then simply run:
> >>> x = Marker.objects.filter(markid = 'TO11')
> >>> print x
>
> in debugger, this basically creates the following simple query:
> DEBUG (44.120) QUERY = u'SELECT "PROD_SCHEMA"."MARKER"."MARKER_ID",
> "PROD_SCHEMA"."MARKER"."MARKID", "PROD_SCHEMA"."MARKER"."CROP_ID",
> "PROD_SCHEMA"."MARKER"."INSID", "PROD_SCHEMA"."MARKER"."INSDATE" FROM
> "PROD_SCHEMA"."MARKER" WHERE "PROD_SCHEMA"."MARKER"."MARKID" = :arg0' -
> PARAMS = (u'TO11',); args=('TO11',)
>
> As you see, in Django this takes 44 seconds to run.
> If I run this exact same query with cx_oracle directly the response time =
> < 0.1sec.
>
> For small tables the performance of django is quite good, so it almost
> seems like django tries to do a count on the table before runnign the query
> or something. Any suggestions on how I can make this lookup faster?
>
> thanks
> joris
>
>
>
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