“FreeBSD:软件安装”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： @@
-搜索软件包
+<pre>
-<source lang="bash">
+mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G
-portsnap fetch
+*************************** 1. row ***************************
-portsnap extract
+           id: 1
-portsnap update
+  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>
-portsnap fetch update
+其中：
+*id	select_id	The SELECT identifier
-pkg search git
+*select_type	None	The SELECT type
-pkg search -o git
+*table	table_name	The table for the output row
-whereis git
+*partitions	partitions	The matching partitions
-echo /usr/ports/*/*git*
+*type	access_type	The join type
-</source>
+*possible_keys	possible_keys	The possible indexes to choose
+*key	key	The index actually chosen
-已安装的软件包
+*key_len	key_length	The length of the chosen key
-<source lang="bash">
+*ref	ref	The columns compared to the index
-pkg info
+*rows	rows	Estimate of rows to be examined
-</source>
+*filtered	filtered	Percentage of rows filtered by table condition
+*Extra	None	Additional information
-安装
+[[Category:Datebase]]
-<source lang="bash">
-pkg install curl
-</source>
-升级
-<source lang="bash">
-pkg upgrade
-</source>
-删除
-<source lang="bash">
-pkg delete curl
-</source>
-[[Category:Linux/Unix]]