Re: Why is ORDER BY ASC is slow but ORDER DESC is fast ? and how can i fix it ?

[Ronald Brown]

Rick James Wrote:
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> Or you could "DROP INDEX comments_count" unless it
> is otherwise needed.


i have dropped index for now and resetting the slow query log, will watch for next 24 hours.,

the query is quite fast now

25 rows in set (0.03 sec)

mysql> explain SELECT * FROM content WHERE enabled = 1 AND category IN (600,601,602,603,604,605,606,607,608,609,610,611,612,613,614,615,616,617,618,619,620) AND upload_date >= '2015-08-31' ORDER BY comments_count ASC LIMIT 900,25\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: content
type: range
possible_keys: upload_date,e_c_d_v,e_d_v,e_c_v,e_v,e_u,e_s_d
key: e_c_d_v
key_len: 8
ref: NULL
rows: 34390
Extra: Using index condition; Using filesort
1 row in set (0.00 sec)