this is a bug, fixed in r4857 of the 0.4 branch.
On Jun 16, 3:14 pm, "Matthew Dennis" <[EMAIL PROTECTED]> wrote:
> Using Postgres 8.3.1
>
> Consider the following script. In SA 0.4.3 it works as intended. In SA
> 0.4.6, it does not. In particular, the time to get the resultset in 0.4.3
> is sub-second. The time in 0.4.6 is about 20 seconds. Also, when running
> on 0.4.3 the memory consumption of the script is constant under 10MB. When
> running on 0.4.6, it grows to hundreds of MB and is dependent on the size of
> the result set. Seems to me that 0.4.3 used a cursor like it was configured
> to and 0.4.6 ignored the server_side_cursors=True parameter to the
> create_engine call. How do I make 0.4.6 use server side cursors?
>
> #!/usr/bin/python
>
> from time import time
> from sqlalchemy import text
> from sqlalchemy import create_engine
>
> stime = time()
> engine = create_engine('postgres://[EMAIL PROTECTED]/postgres',
> server_side_cursors=True, encoding='utf-8')
> conn = engine.connect()
> trans = conn.begin()
> print "have engine, connection, transaction after about %.4f seconds" %
> (time() - stime)
>
> stime = time()
> rs = conn.execute(text("select * from generate_series(1,1000) s0,
> generate_series(1,10000) s1"))
> print "have resultset after about %.4f seconds" % (time() - stime)
>
> count = 0
> stime = time()
> for r in rs:
> count += 1
> print "counted %s rows after about %.4f seconds" % (count, time() - stime)
>
> stime = time()
> rs.close()
> print "closed resultset after about %.4f seconds" % (time() - stime)
>
> stime = time()
> trans.commit()
> print "commited after about %.4f seconds" % (time() - stime)
>
> stime = time()
> conn.close()
> print "closed connection after about %.4f seconds" % (time() - stime)
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