75 lines
3.7 KiB
Plaintext
75 lines
3.7 KiB
Plaintext
select PROCESSLIST_ID from performance_schema.session_connect_attrs limit 1
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into @plid;
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====================================================================
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Testing index for columns PROCESSLIST_ID, ATTR_NAME
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====================================================================
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = "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 session_connect_attrs NULL ref PRIMARY PRIMARY 8 const # 100.00 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID > "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 session_connect_attrs NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID < "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 session_connect_attrs NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid;
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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 session_connect_attrs NULL ref PRIMARY PRIMARY 8 const # 100.00 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = "impossible"
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and ATTR_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 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 ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid
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and ATTR_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 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 ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid
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and ATTR_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 session_connect_attrs NULL ref PRIMARY PRIMARY 8 const # 33.33 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid
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and ATTR_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 session_connect_attrs NULL ref PRIMARY PRIMARY 8 const # 33.33 Using where
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############ Explain for Query ####################################
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explain select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid
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and ATTR_NAME = "_os";
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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 session_connect_attrs NULL const PRIMARY PRIMARY 138 const,const # 100.00 NULL
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############# Explain End #########################################
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flush status;
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select ORDINAL_POSITION
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from performance_schema.session_connect_attrs
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where PROCESSLIST_ID = @plid
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and ATTR_NAME = "_os";
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ORDINAL_POSITION
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#
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OK: handler_read_key incremented
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