Details
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Bug
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Status: Open (View Workflow)
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Major
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Resolution: Unresolved
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10.3(EOL), 10.11, 11.4, 11.8, 12.3
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None
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None
Description
Apply the following diff to the test and observe constant results:
diff --git a/mysql-test/suite/vcol/t/query_cache.test b/mysql-test/suite/vcol/t/query_cache.test
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index 46bcba7d03f..d71cfc70d74 100644
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--- a/mysql-test/suite/vcol/t/query_cache.test
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+++ b/mysql-test/suite/vcol/t/query_cache.test
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@@ -7,9 +7,16 @@ set query_cache_type=1;
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set rand_seed1=1234567890, rand_seed2=20;
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create table t1 (a int, b float as (rand()));
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insert into t1 (a) values (1);
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+disable_query_log;
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+flush tables;
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+enable_query_log;
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--disable_ps2_protocol
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select * from t1;
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select * from t1;
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+select * from t1;
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+select * from t1;
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+select * from t1;
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+select * from t1;
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set global query_cache_type=default;
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select * from t1;
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--enable_ps2_protocol
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Result diff:
CURRENT_TEST: vcol.query_cache
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--- mysql-test/suite/vcol/r/query_cache.result 2026-06-16 23:59:34.534628154 +0400
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+++ mysql-test/suite/vcol/r/query_cache.reject 2026-10-15 21:22:15.252370091 +0400
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@@ -11,10 +11,22 @@
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1 0.449343
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select * from t1;
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a b
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-1 0.797372
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+1 0.449343
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+select * from t1;
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+a b
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+1 0.449343
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+select * from t1;
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+a b
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+1 0.449343
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+select * from t1;
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+a b
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+1 0.449343
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+select * from t1;
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+a b
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+1 0.449343
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set global query_cache_type=default;
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select * from t1;
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a b
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-1 0.638829
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+1 0.797372
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drop table t1;
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# End of 10.11 tests
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Codex explanation:
After FLUSH TABLES, opening a table with a RAND() virtual column fixes the expression under a temporary LEX. RAND() clears safe_to_cache_query there, but the flag is not propagated to the SELECT's LEX. The additional fix is skipped for newly opened TABLE instances (from_share=true).
With query cache enabled, the SELECT is therefore cached, and subsequent identical queries reuse the random value. The fix for MDEV-29186 does not cover this path.
Note: other functions like AI_EMBED() can also be affected.
Attachments
Issue Links
- relates to
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MDEV-36100 Generate vector embeddings automatically on INSERT
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- In Progress
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- Open
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- Closed
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