def checkJoins(self, joins, allAttributes, cachedLHS, cachedRHS):
for join in joins:
if join.joinMethod == 'hash':
lhsCheck = join.lhsKeySchema.fields # This is a list
rhsCheck = join.rhsKeySchema.fields # This is a list
joinAttr = lhsCheck + rhsCheck
contains = all(x in allAttributes for x in joinAttr) and any(
y in cachedRHS.schema().fields for y in joinAttr)
# print(lhsCheck, rhsCheck, contains)
if contains:
keySchema1 = DBSchema('keyschema1', [(lhsCheck[0], 'int')])
keySchema2 = DBSchema('keyschema2', [(rhsCheck[0], 'int')])
hashFn1 = 'hash(' + lhsCheck[0] + ') % 7'
hashFn2 = 'hash(' + rhsCheck[0] + ') % 7'
joinExpr = lhsCheck[0] + ' == ' + rhsCheck[0]
if lhsCheck[0] in cachedLHS.schema().fields:
return True, {
'joinMethod': 'hash',
'lhsHashFn': hashFn1,
'lhsKeySchema': keySchema1,
'rhsHashFn': hashFn2,
'rhsKeySchema': keySchema2,
'joinExpr': joinExpr
}
else:
return True, {
'joinMethod': 'hash',
'lhsHashFn': hashFn2,
'lhsKeySchema': keySchema2,
'rhsHashFn': hashFn1,
'rhsKeySchema': keySchema1,
'joinExpr': joinExpr
}
elif join.joinExpr:
joinAttr = ExpressionInfo(join.joinExpr).getAttributes()
contains = all(x in allAttributes for x in joinAttr)
if contains:
joinAttr1 = joinAttr.pop()
joinAttr2 = joinAttr.pop()
try:
joinAttr.pop()
except KeyError:
pass
# print('There are only two attributes in this, as expected')
keySchema1 = DBSchema('keySchema1', [([joinAttr1, 'int'])])
keySchema2 = DBSchema('keySchema1', [([joinAttr2, 'int'])])
hashFn1 = 'hash(' + joinAttr1 + ') % 7'
hashFn2 = 'hash(' + joinAttr2 + ') % 7'
joinExpr = join.joinExpr
if joinAttr1 in cachedLHS.schema().fields:
return True, {
'joinMethod': 'hash',
'lhsHashFn': hashFn1,
'lhsKeySchema': keySchema1,
'rhsHashFn': hashFn2,
'rhsKeySchema': keySchema2,
'joinExpr': joinExpr
}
else:
return True, {
'joinMethod': 'hash',
'lhsHashFn': hashFn2,
'lhsKeySchema': keySchema2,
'rhsHashFn': hashFn1,
'rhsKeySchema': keySchema1,
'joinExpr': joinExpr
}
else:
return False, None
