4 千万的数据量， postgre order by 优化。

[xmge]

各位大佬，有个这样的数据库优化问题：

select xxxx,xxx from tables where a > xx order by update limit 100;

a 和 update 都有索引

数据量 4 千万，执行 explain analyze 分析 sql 结果如下，主要的花费在于 Recheck Cond,

这个问题如何解决呢？？？

Sort  (cost=2058.65..2059.93 rows=512 width=89) (actual time=513.218..513.274 rows=333 loops=1)
  Sort Key: updated
  Sort Method: quicksort  Memory: 74kB
  ->  Bitmap Heap Scan on Tables_XXX  (cost=20.53..2035.61 rows=512 width=89) (actual time=15.101..512.814 rows=333 loops=1)
        Recheck Cond: ((user_id)::text = 'XXXXXXX'::text)
        Heap Blocks: exact=318
        ->  Bitmap Index Scan on XXXX_INDEX  (cost=0.00..20.41 rows=512 width=0) (actual time=11.006..11.006 rows=333 loops=1)
              Index Cond: ((user_id)::text = 'XXXXXXX'::text)
Planning time: 0.089 ms
Execution time: 513.320 ms

[MoYi123]

min_pk,max_pk = select min(primary_key), max(primary_key) from table where a > xx;
select xxxx from tables where min_pk < pk and pk < max_pk and a > xx order by update limit 100;
可以试一试这样有没有用。
参考了这篇博客
https://github.com/digoal/blog/blob/master/202007/20200710_01.md

[xmge]

@MoYi123 好的，我看一下，感谢啦

[yuan434356430]

把 postgre 的并行打开试试会不会变快