Bring transaction_cost_limit into master (re-target of #8) - #9
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Caps the cumulative estimated plan cost of the statements executed in one transaction, so a batch interface cannot smuggle unbounded work through many individually-cheap statements. Requested for throttling PostgREST batch endpoints and mapping the error to HTTP 429. - New PGC_SUSET GUC plan_filter.transaction_cost_limit, default 0 (off), same SQLSTATE (54001) as the statement limit - Accounting happens in a new ExecutorStart hook, not the planner hook, so every execution is charged: a PREPARE/EXECUTE loop over a cached generic plan cannot evade a plan-time accumulator - A transaction callback zeroes the accumulator on commit/abort/prepare; ROLLBACK TO SAVEPOINT does not refund cost already charged - Plain EXPLAIN and parallel workers are exempt; filter_select_only applies as it does to the statement limit - Regression tests cover the reset, no-refund, generic-plan, EXPLAIN, filter_select_only, and SQLSTATE behaviors - README, ADR 0004, and ARCHITECTURE.md document the design, and warn that plan-cost limits are not a security boundary against a hostile role: the cost estimate is computed from USERSET planner GUCs a client can lower to evade either limit
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Brings the
transaction_cost_limitfeature (issue #4) intomasterand applies final 1.0.0 release polish.Why this PR exists: #8 (the feature) was opened against the stacked
modernize-pg14-18-cibranch so its review diff would stay clean while #7 was open. But #7 merged that branch tomasterfirst, and #8 then merged into the already-carried branch — so the feature never reachedmaster. This re-applies the reviewed commits directly on currentmaster.Contents:
transaction_cost_limitimplementation — byte-identical to what CI validated green on Add plan_filter.transaction_cost_limit (issue #4) #8; already reviewed there.d36988d): reword the README intro to describe both cost criteria (the old text said "the only criterion" is the per-statement cost, contradicting the new feature), and drop thedocs/superpowers/design-spec process artifact — its rationale is preserved indocs/adr/0004— gitignoring that path.Merging this makes
masterthe complete, tagged-ready 1.0.0 state.