“FreeBSD:软件安装”与“MySQL explain”:页面之间的差异

来自WHY42
(页面间差异)
imported>Riguz
(创建页面,内容为“搜索软件包 <source lang="bash"> pkg search git pkg search -o git whereis git echo /usr/ports/*/*git* </source> Category:Linux/Unix”)
 
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搜索软件包
<pre>
<source lang="bash">
mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G
pkg search git
*************************** 1. row ***************************
pkg search -o git
          id: 1
whereis git
  select_type: SIMPLE
echo /usr/ports/*/*git*
        table: vehicle_prod
</source>
  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)
</pre>


[[Category:Linux/Unix]]
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
[[Category:Datebase]]

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