Push single-variable WHERE predicates across all MATCH clauses#4
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Build the pushdown map once from every non-optional MATCH's WHERE so a single-variable predicate prunes the scan that first binds its variable, even when the WHERE is written on a later clause. Previously pushdown was per-clause, so `MATCH (t)-[:R]->(c) MATCH (c)-..-(x) WHERE t.name = ...` materialized the entire (t)-[:R]->(c) relation before filtering t. The global map is only applied while evaluating non-optional MATCH patterns (gated by pushdown_active); it must stay off during OPTIONAL MATCH expansion and EXISTS subqueries, where pruning a candidate that fails a single-variable predicate can change results — e.g. an `OPTIONAL MATCH ... WHERE t IS NULL` anti-join would otherwise null-fill every row and wrongly keep them all. Adds the cross-clause pushdown regression test and a pushdown/OPTIONAL MATCH safety test. Co-authored-by: River <shopify.river@shopify.com>
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Builds the pushdown map once from every non-optional MATCH's WHERE, so a single-variable predicate prunes the scan that first binds its variable even when the WHERE is written on a later clause.
MATCH (t)-[:R]->(c) MATCH (c)-..-(x) WHERE t.name = ...previously materialized the whole(t)-[:R]->(c)relation before filteringt.Review note / correctness fix
The original patch made the pushdown map global and always-on, which introduced a latent correctness bug: it would then be applied inside
OPTIONAL MATCHandEXISTS. A pushedt IS NULLpredicate on an optionally-boundtwould prune every realt, null-fill every row, and wrongly keep them all (breaking the anti-join). This PR keeps the global map but gates application to non-optional MATCH pattern evaluation (pushdown_active), restoring the pre-existing invariant that pushdown never fires in OPTIONAL MATCH / EXISTS.Includes the cross-clause regression test and a new
pushdown_optional_safetytest that fails against the always-on variant.Co-authored-by: River shopify.river@shopify.com