From: Derek Downey
Date: November 4 2011 4:54pm
Subject: Re: Deleting Records in Big tables
List-Archive: http://lists.mysql.com/mysql/226241
Message-Id: <0F1F2754-5BA1-4082-BE1F-7747CD5A2163@orange-pants.com>
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Be careful deleting with limit. If you're replicating, you're not =
guaranteed the same order of those  you've deleted.

Perhaps a better way to delete in smaller chunks is to increase the id =
value:

DELETE FROM my_big_table WHERE id> 5000;
DELETE FROM my_big_table WHERE id> 4000;
etc

-- Derek

On Nov 4, 2011, at 12:47 PM, Andy Wallace wrote:

> I've had some luck in the past under similar restrictions deleting in
> chunks:
>=20
> delete from my_big_table where id > 2474 limit 1000
>=20
> But really, the best way is to buy some more disk space and use the
> new table method
>=20
> On 11/4/11 1:44 AM, Adarsh Sharma wrote:
>> Thanks Anand,
>>=20
>>=20
>> Ananda Kumar wrote:
>>> Why dont you create a new table where id < 2474, rename the original =
table to "_old" and the new table to actual table name.
>> I need to delete rows from 5 tables each > 50 GB , & I don't have =
sufficient space to store extra data.
>> My application loads 2 GB data daily in my databases.
>>>=20
>>> or
>>> You need to write a stored proc to loop through rows and delete, =
which will be faster.
>>=20
>> Can U provide me a simple example of stored proc
>>>=20
>>> Doing just a simple "delete" statement, for deleting huge data will =
take ages.
>>=20
>> Even the Create Index command on ID takes hours too complete.
>>=20
>> I think there is no easiest way to delete that rows from mysql =
tables.
>>=20
>>=20
>>=20
>>=20
>>=20
>>>=20
>>> regards
>>> anandkl
>>>=20
>>> On Fri, Nov 4, 2011 at 12:52 PM, Adarsh Sharma =
<adarsh.sharma@stripped <mailto:adarsh.sharma@stripped>> wrote:
>>>=20
>>>=20
>>> Dear all,
>>>=20
>>> Today I need to delete some records in > 70 GB tables.
>>> I have 4 tables in mysql database.
>>>=20
>>> my delete command is :-
>>>=20
>>> delete from metadata where id>2474;
>>>=20
>>> but it takes hours to complete.
>>>=20
>>> One of my table structure is as :-
>>>=20
>>> CREATE TABLE `metadata` (
>>> `meta_id` bigint(20) NOT NULL AUTO_INCREMENT,
>>> `id` bigint(20) DEFAULT NULL,
>>> `url` varchar(800) DEFAULT NULL,
>>> `meta_field` varchar(200) DEFAULT NULL,
>>> `meta_value` varchar(2000) DEFAULT NULL,
>>> `dt_stamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
>>> PRIMARY KEY (`meta_id`)
>>> ) ENGINE=3DInnoDB AUTO_INCREMENT=3D388780373 ;
>>>=20
>>>=20
>>> Please let me know any quickest way to do this.
>>> I tried to create indexes in these tables on id, but this too
>>> takes time.
>>>=20
>>>=20
>>>=20
>>> Thanks
>>>=20
>>> -- MySQL General Mailing List
>>> For list archives: http://lists.mysql.com/mysql
>>> To unsubscribe: http://lists.mysql.com/mysql?unsub=3Danandkl@stripped=

>>>=20
>>>=20
>>=20
>>=20
>=20
> --=20
> Andy Wallace
> iHOUSEweb, Inc.
> awallace@stripped
> (866) 645-7700 ext 219
> --
> There are two ways to build software:
> Make it so simple that there are obviously no bugs,
> or make it so complex that there are no obvious bugs.
>=20
> --=20
> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe:    =
http://lists.mysql.com/mysql?unsub=3Dderek@stripped
>=20