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Add a planner support function for numeric generate_series().

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This allows the planner to estimate the number of rows returned by
generate_series(numeric, numeric[, numeric]), when the input values
can be estimated at plan time.

Song Jinzhou, reviewed by Dean Rasheed and David Rowley.

Discussion: https://postgr.es/m/tencent_F43E7F4DD50EF5986D1051DE8DE547910206%40qq.com
Discussion: https://postgr.es/m/tencent_1F6D5B9A1545E02FD7D0EE508DFD056DE50A%40qq.com
This commit is contained in:
Dean Rasheed
2024-12-02 11:37:57 +00:00
parent 3315235845
commit 97173536ed
5 changed files with 232 additions and 3 deletions
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38
src/test/regress/sql/misc_functions.sql
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@@ -311,6 +311,44 @@ false, true, false, true);
-- the support function.
SELECT * FROM generate_series(TIMESTAMPTZ '2024-02-01', TIMESTAMPTZ '2024-03-01', INTERVAL '0 day') g(s);
--
-- Test the SupportRequestRows support function for generate_series_numeric()
--
-- Ensure the row estimate matches the actual rows
SELECT explain_mask_costs($$
SELECT * FROM generate_series(1.0, 25.0) g(s);$$,
true, true, false, true);
-- As above but with non-default step
SELECT explain_mask_costs($$
SELECT * FROM generate_series(1.0, 25.0, 2.0) g(s);$$,
true, true, false, true);
-- Ensure the estimates match when step is decreasing
SELECT explain_mask_costs($$
SELECT * FROM generate_series(25.0, 1.0, -1.0) g(s);$$,
true, true, false, true);
-- Ensure an empty range estimates 1 row
SELECT explain_mask_costs($$
SELECT * FROM generate_series(25.0, 1.0, 1.0) g(s);$$,
true, true, false, true);
-- Ensure we get the default row estimate for error cases (infinity/NaN values
-- and zero step size)
SELECT explain_mask_costs($$
SELECT * FROM generate_series('-infinity'::NUMERIC, 'infinity'::NUMERIC, 1.0) g(s);$$,
false, true, false, true);
SELECT explain_mask_costs($$
SELECT * FROM generate_series(1.0, 25.0, 'NaN'::NUMERIC) g(s);$$,
false, true, false, true);
SELECT explain_mask_costs($$
SELECT * FROM generate_series(25.0, 2.0, 0.0) g(s);$$,
false, true, false, true);
-- Test functions for control data
SELECT count(*) > 0 AS ok FROM pg_control_checkpoint();
SELECT count(*) > 0 AS ok FROM pg_control_init();