125 lines
6.5 KiB
Plaintext
125 lines
6.5 KiB
Plaintext
create database explain_test_db;
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use explain_test_db;
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truncate table performance_schema.events_statements_summary_by_digest;
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select 1;
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1
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1
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select digest from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = 'explain_test_db' limit 1
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into @digest;
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use test;
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====================================================================
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Testing index for columns SCHEMA_NAME, DIGEST, BUCKET_NUMBER
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====================================================================
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 259 const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME > "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ALL SCHEMA_NAME NULL NULL NULL # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME < "2";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ALL SCHEMA_NAME NULL NULL NULL # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 259 const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "impossible"
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and DIGEST = "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 518 const,const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 518 const,const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST > "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 259 const # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST < "2";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 259 const # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 518 const,const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "impossible"
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and DIGEST = "impossible"
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and BUCKET_NUMBER = "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest
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and BUCKET_NUMBER = "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL const SCHEMA_NAME SCHEMA_NAME 522 const,const,const # 100.00 NULL
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest
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and BUCKET_NUMBER > "impossible";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 518 const,const # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest
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and BUCKET_NUMBER < "2";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL ref SCHEMA_NAME SCHEMA_NAME 518 const,const # 33.33 Using where
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############ Explain for Query ####################################
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explain select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest
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and BUCKET_NUMBER = 0;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE events_statements_histogram_by_digest NULL const SCHEMA_NAME SCHEMA_NAME 522 const,const,const # 100.00 NULL
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############# Explain End #########################################
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flush status;
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select COUNT_BUCKET
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from performance_schema.events_statements_histogram_by_digest
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where SCHEMA_NAME = "explain_test_db"
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and DIGEST = @digest
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and BUCKET_NUMBER = 0;
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COUNT_BUCKET
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#
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OK: handler_read_key incremented
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drop database explain_test_db;
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