On Mon, 18 Jun 2001, Patrizio Bruno wrote:
> "select max(field) from table" returns the greatest field's value in the first
> file of the RAID table (successive files are not considered), adding a where
> clause (for ex. "select max(field) from table where field2 >= 2000000") the
> problem seems not to exist. I don't know if the bug is limited to the
> 'max()' function, but, for the use I make of mysql, this is a big problem.
I think this is impossible. MySQL-s higher lever doesn't know anything
about RAID and because this cannot return rows based on location in files.
You did not supplied enough information to reproduce the bug or even
understand its nature. From current niformation I believe that you have
index file broken in smoe reason and because this MySQL of course can
return wrong result not depenging if it is raided or not.
Run "REPAIR TABLE urlword" and see if problem persists. If yes, give me a
repeatable testcase by mysqldump-ing this table and giving clear example
on which exact commands he gave what exact answer and I try to reproduce
it on my own computer. I cannot fix it before I can reproduce it.
> Environment:
> Linux 2.2.19
> MySQL 3.23.38
> mysql's data directory is on a NFS partition
>
> below the create statement I used to create my table:
>
> create table urlword(url_id integer auto_increment primary key,
> site_id integer not null,
> deleted tinyint DEFAULT 0 NOT NULL,
> url varchar(128) not null,
> next_index_time INT NOT NULL,
> status int(11) DEFAULT '0' NOT NULL,
> crc char(32) DEFAULT '' NOT NULL,
> last_modified varchar(32) DEFAULT '' NOT NULL,
> etag varchar(48) DEFAULT '' NOT NULL,
> last_index_time INT NOT NULL,
> referrer int(11) DEFAULT '0' NOT NULL,
> tag int(11) DEFAULT '0' NOT NULL,
> hops int(11) DEFAULT '0' NOT NULL,
> redir integer,
> origin integer,
> unique index(url),
> index(next_index_time),
> index(hops,next_index_time),
> index crc (site_id,crc(8))) DELAY_KEY_WRITE=1 RAID_TYPE=STRIPED RAID_CHU
> NKS=8 RAID_CHUNKSIZE=153600 PACK_KEYS=1 TYPE=MyISAM;
>
> the mysql configuration file is my-huge.cnf taken from the mysql's
> source-distribution.
>
BTW, why did you change the chunksize? By default it is 256000 and I
tested it for speed with many different values. 256000 seemed to be best
value. If you have any experience showing that I was wrong, please share
it with me.
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