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a0cb7551a4
Introduced a print_key_value function to makes sure that the trace prints data in readable format for readable characters and the rest of the characters are printed as hexadecimal.
55 lines
1.4 KiB
Plaintext
55 lines
1.4 KiB
Plaintext
create or replace table t1 (col1 char(10) character set ucs2, filler char(100), key(col1)) ;
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insert into t1 values ('a', 'a');
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insert into t1 values ('a', 'a');
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set optimizer_trace=1;
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explain format=json select * from t1 force index(col1) where col1 >='a';
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"table": {
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"table_name": "t1",
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"access_type": "range",
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"possible_keys": ["col1"],
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"key": "col1",
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"key_length": "21",
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"used_key_parts": ["col1"],
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"rows": 2,
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"filtered": 100,
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"index_condition": "t1.col1 >= 'a'"
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}
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}
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}
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select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
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JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives'))
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[
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{
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"range_scan_alternatives":
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[
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{
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"index": "col1",
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"ranges":
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[
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"(a) <= (col1)"
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],
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"rowid_ordered": false,
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"using_mrr": false,
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"index_only": false,
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"rows": 2,
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"cost": 3.7609,
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"chosen": true
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}
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],
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"analyzing_roworder_intersect":
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{
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"cause": "too few roworder scans"
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},
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"analyzing_index_merge_union":
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[
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]
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}
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]
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drop table t1;
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