Details
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Task
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
Description
Document all performance schema tables using per-column COMMENT, like in
--- a/storage/perfschema/table_file_instances.cc
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+++ b/storage/perfschema/table_file_instances.cc
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@@ -49,9 +49,9 @@ table_file_instances::m_share=
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sizeof(PFS_simple_index),
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&m_table_lock,
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{ C_STRING_WITH_LEN("CREATE TABLE file_instances("
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- "FILE_NAME VARCHAR(512) not null,"
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- "EVENT_NAME VARCHAR(128) not null,"
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- "OPEN_COUNT INTEGER unsigned not null)") },
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+ "FILE_NAME VARCHAR(512) not null comment 'File name',"
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+ "EVENT_NAME VARCHAR(128) not null comment 'Instrument name associated with the file',"
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+ "OPEN_COUNT INTEGER unsigned not null comment 'Open handles on the file. A value of greater than zero means that the file is currently open')") },
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false /* perpetual */
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};
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After that one can see the built-in documentation with
show create table performance_schema.file_instances |
or, better, with
select column_name, column_comment from information_schema.columns where table_schema='performance_schema' and table_name='file_instances' |
returning
+-------------+----------------------------------------------------------------------------------------------+
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| column_name | column_comment |
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+-------------+----------------------------------------------------------------------------------------------+
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| FILE_NAME | File name |
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| EVENT_NAME | Instrument name associated with the file |
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| OPEN_COUNT | Open handles on the file. A value of greater than zero means that the file is currently open |
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+-------------+----------------------------------------------------------------------------------------------+
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The documentation text is taken from https://mariadb.com/kb/en/performance-schema-file_instances-table/