Cryptic list index out of range exception when pushing computations to postgres

[shrjain]

For the following query:
`k = scan(kmercntnorm_11_forward_Pkmer);
--kmers = select * from k;

------- original query
X = select a.sampleid as asample, b.sampleid as bsample,
case when a.norm_cnt < b.norm_cnt then a.norm_cnt else b.norm_cnt end as minv
from k a, k b
where a.kmer = b.kmer
and a.sampleid < b.sampleid;

Y = select asample, bsample, 1 - sum(minv) as BCdis
from X;
store(Y, BC);`

when push_sql is false, the query runs fine, but when push_sql is true, the compilation fails with the following trace:
Traceback (most recent call last):
File "/opt/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 570, in dispatch
return method(_args, *_kwargs)
File "/usr/local/myria-web/appengine/myria_web_main.py", line 504, in post
multiway_join=multiway_join, push_sql=push_sql)
File "/usr/local/myria-web/appengine/myria_web_main.py", line 124, in get_physical_plan
multiway_join=multiway_join, push_sql=push_sql)
File "/usr/local/myria-web/appengine/myria_web_main.py", line 110, in get_plan
push_sql=push_sql)
File "/usr/local/myria-web/appengine/raco/myrial/interpreter.py", line 451, in get_physical_plan
return self.get_physical_plan_for(target_phys_algebra, **kwargs)
File "/usr/local/myria-web/appengine/raco/myrial/interpreter.py", line 440, in get_physical_plan_for
return optimize(logical_plan, **kwargs)
File "/usr/local/myria-web/appengine/raco/compile.py", line 70, in optimize
return optimize_by_rules(expr, target.opt_rules(**kwargs))
File "/usr/local/myria-web/appengine/raco/compile.py", line 59, in optimize_by_rules
expr = recursiverule(expr)
File "/usr/local/myria-web/appengine/raco/compile.py", line 44, in recursiverule
newe = rule(e)
File "/usr/local/myria-web/appengine/raco/rules.py", line 31, in call
return self.fire(expr)
File "/usr/local/myria-web/appengine/raco/backends/myria/myria.py", line 1500, in fire
sql_plan = cat.get_sql(expr)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 185, in _get_unary_sql
input = self.get_sql(plan.input).alias("input")
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 247, in get_sql
return self._get_unary_sql(plan)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 190, in _get_unary_sql
cond = self._convert_expr(cols, plan.condition, input_sch)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 116, in _convert_expr
return self._convert_binary_expr(cols, expr, input_scheme)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 156, in _convert_binary_expr
right = self._convert_expr(cols, expr.right, input_scheme)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 110, in _convert_expr
return self._convert_attribute_ref(cols, expr, input_scheme)
File "/usr/local/myria-web/appengine/raco/backends/sql/catalog.py", line 133, in _convert_attribute_ref
return cols[expr.position]
IndexError: list index out of range

[bmyerz]

Looks like a bug in get_sql having to do with attribute indexes, perhaps after a join or after a projection. I would print out what the positions are as the plan is traversed.