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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10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 10.10, 10.11
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None
Description
SET optimizer_trace= 'enabled=on'; |
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CREATE TABLE t (col_bit BIT) ENGINE=MyISAM; |
INSERT INTO t VALUES (1); |
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SELECT * FROM t t1 WHERE EXISTS ( SELECT * FROM t t2 WHERE t2.col_bit <= t1.col_bit ); |
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select json_valid(trace), json_compact(trace) from information_schema.optimizer_trace; |
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# Cleanup
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DROP TABLE t; |
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10.5 b8f4b984 |
SELECT * FROM t t1 WHERE EXISTS ( SELECT * FROM t t2 WHERE t2.col_bit <= t1.col_bit ); |
col_bit
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select json_valid(trace), json_compact(trace) from information_schema.optimizer_trace; |
json_valid(trace) json_compact(trace)
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0 NULL |
Warnings:
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Warning 4036 Character disallowed in JSON in argument 1 to function 'json_compact' at position 2451 |
The problematic part of the trace is
{
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"condition_on_constant_tables": "<in_optimizer>(1,exists(/* select#2 */ select 1 from t t2 where t2.col_bit <= ^A limit 1))",
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"evaluated": "false",
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"cause": "expensive cond"
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},
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{
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"attaching_conditions_to_tables": {
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"original_condition": "<in_optimizer>(1,exists(/* select#2 */ select 1 from t t2 where t2.col_bit <= ^A limit 1))",
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"attached_conditions_computation": [],
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"attached_conditions_summary": []
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}
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},
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{
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"join_optimization": {
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"select_id": 2,
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"steps": [
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{
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"condition_processing": {
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"condition": "WHERE",
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"original_condition": "t2.col_bit <= ^A",
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"steps": [
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{
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"transformation": "equality_propagation",
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"resulting_condition": "t2.col_bit <= ^A"
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},
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{
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"transformation": "constant_propagation",
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"resulting_condition": "t2.col_bit <= ^A"
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},
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{
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"transformation": "trivial_condition_removal",
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"resulting_condition": "t2.col_bit <= ^A"
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}
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where ^A represent the problematic symbols.
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