“Main Page”与“MySQL explain”：页面之间的差异

2018年9月18日 (二) 09:16的版本

mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: vehicle_prod
   partitions: NULL
         type: index
possible_keys: NULL
          key: idx_vehicle_prod_fin
      key_len: 203
          ref: NULL
         rows: 3182812
     filtered: 11.11
        Extra: Using where; Using index
1 row in set, 1 warning (0.00 sec)

其中：

id select_id The SELECT identifier
select_type None The SELECT type
table table_name The table for the output row
partitions partitions The matching partitions
type access_type The join type
possible_keys possible_keys The possible indexes to choose
key key The index actually chosen
key_len key_length The length of the chosen key
ref ref The columns compared to the index
rows rows Estimate of rows to be examined
filtered filtered Percentage of rows filtered by table condition
Extra None Additional information

@@ 第1行： / 第1行： @@
-<strong>MediaWiki has been installed.</strong>
+<pre>
+mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G
+*************************** 1. row ***************************
+           id: 1
+  select_type: SIMPLE
+        table: vehicle_prod
+   partitions: NULL
+         type: index
+possible_keys: NULL
+          key: idx_vehicle_prod_fin
+      key_len: 203
+          ref: NULL
+         rows: 3182812
+     filtered: 11.11
+        Extra: Using where; Using index
+row in set, 1 warning (0.00 sec)
+</pre>
-Consult the [https://www.mediawiki.org/wiki/Special:MyLanguage/Help:Contents User's Guide] for information on using the wiki software.
+其中：
+*id	select_id	The SELECT identifier
-== Getting started ==
+*select_type	None	The SELECT type
-* [https://www.mediawiki.org/wiki/Special:MyLanguage/Manual:Configuration_settings Configuration settings list]
+*table	table_name	The table for the output row
-* [https://www.mediawiki.org/wiki/Special:MyLanguage/Manual:FAQ MediaWiki FAQ]
+*partitions	partitions	The matching partitions
-* [https://lists.wikimedia.org/postorius/lists/mediawiki-announce.lists.wikimedia.org/ MediaWiki release mailing list]
+*type	access_type	The join type
-* [https://www.mediawiki.org/wiki/Special:MyLanguage/Localisation#Translation_resources Localise MediaWiki for your language]
+*possible_keys	possible_keys	The possible indexes to choose
-* [https://www.mediawiki.org/wiki/Special:MyLanguage/Manual:Combating_spam Learn how to combat spam on your wiki]
+*key	key	The index actually chosen
+*key_len	key_length	The length of the chosen key
+*ref	ref	The columns compared to the index
+*rows	rows	Estimate of rows to be examined
+*filtered	filtered	Percentage of rows filtered by table condition
+*Extra	None	Additional information
+[[Category:Datebase]]