36 lines
933 B
Python
36 lines
933 B
Python
# Test NOWAIT with an updated tuple chain.
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setup
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{
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CREATE TABLE foo (
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id int PRIMARY KEY,
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data text NOT NULL
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);
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INSERT INTO foo VALUES (1, 'x');
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}
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teardown
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{
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DROP TABLE foo;
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}
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session s1
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setup { BEGIN; }
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step s1a { SELECT * FROM foo WHERE pg_advisory_lock(0) IS NOT NULL FOR UPDATE NOWAIT; }
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step s1b { COMMIT; }
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session s2
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step s2a { SELECT pg_advisory_lock(0); }
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step s2b { UPDATE foo SET data = data; }
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step s2c { BEGIN; }
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step s2d { UPDATE foo SET data = data; }
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step s2e { SELECT pg_advisory_unlock(0); }
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step s2f { COMMIT; }
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# s1 takes a snapshot but then waits on an advisory lock, then s2
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# updates the row in one transaction, then again in another without
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# committing, before allowing s1 to proceed to try to lock a row;
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# because it has a snapshot that sees the older version, we reach the
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# waiting code in EvalPlanQualFetch which ereports when in NOWAIT mode.
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permutation s2a s1a s2b s2c s2d s2e s1b s2f
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