BUG: Repeated compilation of the same expression gives different results

[cpcloud]

This also appears to be due to some global state changing during compilation:

In [1]: con = ibis.postgres.connect(database='ibis_testing')

In [2]: t = con.table('batting')

In [3]: print(t.sort_by(ibis.desc(t.playerID)).count().compile().compile())
SELECT count(%(count_1)s) AS count 
FROM batting AS t0 ORDER BY t0."playerID" DESC

In [4]: con = ibis.postgres.connect(database='ibis_testing')

In [5]: t = con.table('batting')

In [6]: print(t.sort_by(ibis.desc(t.playerID)).count().compile().compile())
SELECT count(%(count_1)s) AS count 
FROM (SELECT t1."playerID" AS "playerID", t1."yearID" AS "yearID", t1.stint AS stint, t1."teamID" AS "teamID", t1."lgID" AS "lgID", t1."G" AS "G", t1."AB" AS "AB", t1."R" AS "R", t1."H" AS "H", t1."X2B" AS "X2B", t1."X3B" AS "X3B", t1."HR" AS "HR", t1."RBI" AS "RBI", t1."SB" AS "SB", t1."CS" AS "CS", t1."BB" AS "BB", t1."SO" AS "SO", t1."IBB" AS "IBB", t1."HBP" AS "HBP", t1."SH" AS "SH", t1."SF" AS "SF", t1."GIDP" AS "GIDP" 
FROM batting AS t1 ORDER BY t1."playerID" DESC) AS t0

[cpcloud]

This is due to using toolz.memoize as a decorator, which caches the result of every call.