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perf: Simplify plans by deferring aliasing above joins where possible #2253

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perf: Simplify plans by deferring aliasing above joins where possible #2253

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79 changes: 76 additions & 3 deletions bigframes/core/rewrite/select_pullup.py
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,10 @@ def pull_up_select_unary(node: nodes.UnaryNode) -> nodes.BigFrameNode:
if not isinstance(child, nodes.SelectionNode):
return node

# case where selection must be kept in place to prevent ambiguity
if set(child.child.ids) & set(node.defined_variables):
return node

# Schema-preserving nodes
if isinstance(
node,
Expand Down Expand Up @@ -157,9 +161,78 @@ def pull_up_select_unary(node: nodes.UnaryNode) -> nodes.BigFrameNode:
return node


def pull_up_selects_under_join(node: nodes.JoinNode) -> nodes.JoinNode:
# Can in theory pull up selects here, but it is a bit dangerous, in particular or self-joins, when there are more transforms to do.
# TODO: Safely pull up selects above join
def pull_up_selects_under_join(node: nodes.JoinNode) -> nodes.BigFrameNode:
if isinstance(node.left_child, nodes.SelectionNode) and isinstance(
node.right_child, nodes.SelectionNode
):
conflicts = set(node.left_child.child.ids) & set(node.right_child.child.ids)
if not conflicts:
lmap = {id: ref.id for ref, id in node.left_child.input_output_pairs}
rmap = {id: ref.id for ref, id in node.right_child.input_output_pairs}
new_join = nodes.JoinNode(
node.left_child.child,
node.right_child.child,
conditions=tuple(
(lref.remap_column_refs(lmap), rref.remap_column_refs(rmap))
for lref, rref in node.conditions
),
type=node.type,
propogate_order=node.propogate_order,
)
new_select = nodes.SelectionNode(
new_join,
(
*node.left_child.input_output_pairs,
*node.right_child.input_output_pairs,
),
)
return new_select
elif isinstance(node.left_child, nodes.SelectionNode):
conflicts = set(node.left_child.child.ids) & set(node.right_child.ids)
if not conflicts:
lmap = {id: ref.id for ref, id in node.left_child.input_output_pairs}
new_join = nodes.JoinNode(
node.left_child.child,
node.right_child,
conditions=tuple(
(lref.remap_column_refs(lmap), rref)
for lref, rref in node.conditions
),
type=node.type,
propogate_order=node.propogate_order,
)
new_select = nodes.SelectionNode(
new_join,
(
*node.left_child.input_output_pairs,
*(nodes.AliasedRef.identity(id) for id in node.right_child.ids),
),
)
return new_select

elif isinstance(node.right_child, nodes.SelectionNode):
conflicts = set(node.right_child.child.ids) & set(node.left_child.ids)
if not conflicts:
rmap = {id: ref.id for ref, id in node.right_child.input_output_pairs}
new_join = nodes.JoinNode(
node.left_child,
node.right_child.child,
conditions=tuple(
(lref, rref.remap_column_refs(rmap))
for lref, rref in node.conditions
),
type=node.type,
propogate_order=node.propogate_order,
)
new_select = nodes.SelectionNode(
new_join,
(
*(nodes.AliasedRef.identity(id) for id in node.left_child.ids),
*node.right_child.input_output_pairs,
),
)
return new_select

return node


Expand Down