8 messages in com.mysql.lists.clusterquery performance slow
FromSent OnAttachments
Bob Pisani25 Jul 2007 08:43 
Anatoly Pidruchny25 Jul 2007 08:59 
Bob Pisani25 Jul 2007 09:01 
Bob Pisani25 Jul 2007 09:02 
Brian Moon25 Jul 2007 15:11 
Bob Pisani26 Jul 2007 06:08 
Bob Pisani26 Jul 2007 07:22 
Brian Moon26 Jul 2007 07:43 
Subject:query performance slow
From:Bob Pisani (bpis@schonfeld.com)
Date:07/25/2007 08:43:59 AM
List:com.mysql.lists.cluster

Hey all,

I'm doing some testing of cluster, 5.1.20, on SuSE 10.2. 1 mysql node, 2 data nodes. I have a disk based table, orders, with a primary key on order time and order id. I loaded 1M+ rows into the table and queried as follows:

select * from orders where order_id = 'h0r50000145096' and order_time = '20070718093222'; .... 1 row in set (0.01 sec)

select * from orders where order_id = 'h0r50000145096' and order_time > '20070718090000' and order_time < '20070718100000'; .... 1 row in set (1 min 27.38 sec)

Running an explain on the second query shows: +----+-------------+-------------+-------+---------------+---------+-------- -+------+------+-----------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------------+-------+---------------+---------+-------- -+------+------+-----------------------------------+ | 1 | SIMPLE | orders | range | PRIMARY | PRIMARY | 24 | NULL | 1 | Using where with pushed condition | +----+-------------+-------------+-------+---------------+---------+-------- -+------+------+-----------------------------------+

I know the first query is using the primary key, and it would seem that the second query is supposed to use the ordered index created with the primary hash key. Ndb_desc shows: .... -- Indexes -- PRIMARY KEY(ORDER_ID, ORDER_TIME) - UniqueHashIndex PRIMARY(ORDER_TIME, ORDER_ID) - OrderedIndex

The question is am I missing something? When I've loaded a few more million rows in, the second query practically never finishes. I would expect that a range query would hit the ordered index and be somewhat performant. Thoughts?

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