我正在尝试诊断为什么特定查询对sqlite的速度很慢.关于
how the query optimizer works似乎有很多信息,但关于如何实际诊断问题的信息很少.
特别是,当我分析数据库时,我得到了预期的sqlite_stat1表,但我不知道stat列告诉我什么.示例行是：
- MyTable,ix_id,25112 1 1 1 1
“25112 1 1 1 1”究竟是什么意思？
作为一个更广泛的问题,有没有人有关于诊断sqlite查询性能的最佳工具和技术的任何好资源？
谢谢
来自analyze.c：
- /* Store the results.
- **
- ** The result is a single row of the sqlite_stmt1 table. The first
- ** two columns are the names of the table and index. The third column
- ** is a string composed of a list of integer statistics about the
- ** index. The first integer in the list is the total number of entires
- ** in the index. There is one additional integer in the list for each
- ** column of the table. This additional integer is a guess of how many
- ** rows of the table the index will select. If D is the count of distinct
- ** values and K is the total number of rows,then the integer is computed
- ** as:
- **
- ** I = (K+D-1)/D
- **
- ** If K==0 then no entry is made into the sqlite_stat1 table.
- ** If K>0 then it is always the case the D>0 so division by zero
- ** is never possible.
