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Re: Verifing Data Integrity
From: bob b <robertcb-1(at)comcast.net>
Date: Sun Jul 15 2007 - 05:34:35 EDT
>> To thoroughly verify data in a table slave/master, first stop the
>> db applications.
>>
>> Then sum any numeric columns (I prefer a floating columns.) e.g.,
>>
>> select sum(columnfp1), sum(colmnfp2) from table1;
>>
>> Do this on both master and slave. Should point out that if you
>> choose an index with numeric value it will be much faster.
>>
>>
>> Bob B
>>
>> ----- Original Message ----
>> From: Andrew Brosnan <andrew@broscom.com>
>> To: Paul Sindelar <paul.lists@mnwebhost.net>
>> Cc: replication@lists.mysql.com
>> Sent: Saturday, July 14, 2007 6:14:55 PM
>> Subject: Re: Verifing Data Integrity
>>
>> On 7/14/07 at 12:18 PM, paul.lists@mnwebhost.net (Paul Sindelar)
>> wrote:
>>
>>
>>> Does anyone know a reliable/efficient way of thoroughly verifying
>>> the integrity of a slave?
>>>
>>
>> Would this be done on a routine basis? I think it's more realistic
>> to do
>> routine sanity checks - perhaps you already do. What I do is check
>> for
>> same number of records on master and slave, thoroughly verify
>> *some* of
>> the data by checking random rows, compare file sizes, etc. I can't
>> imagine going through bit by bit without suspecting a problem. I
>> think
>> I'd be more likely to reset the slave with a new snapshot of the
>> masters
>> data. :-)
>>
>> Regards,
>> Andrew
>>
>>
>> --
>> MySQL Replication Mailing List
>> For list archives: http://lists.mysql.com/replication
>> To unsubscribe: http://lists.mysql.com/replication?
>> unsub=robertcb@yahoo.com
>>
>>
>>
>>
>>
>>
>>
>> _____________________________________________________________________
>> _______________
>> Park yourself in front of a world of choices in alternative
>> vehicles. Visit the Yahoo! Auto Green Center.
>> http://autos.yahoo.com/green_center/
>>
>
Date: Sun Jul 15 2007 - 05:34:35 EDT
What I meant was If you have an index ind1 that has a numeric key
say key1 then
select sum(key1) from table1 order by key1; (this is a special case and not general )
This will likely not access the table and report the sum of key1 using only the idex ind1. It is probably not a good idea to sum (primary key) but something else like transaction # which might be indexed.
But any numeric item can be summed whether it is indexed or not and will normally scan the entire table.
On Jul 15, 2007, at 12:52 AM, Darpan Dinker wrote:
> R Bankay wrote:
>> To thoroughly verify data in a table slave/master, first stop the
>> db applications.
>>
>> Then sum any numeric columns (I prefer a floating columns.) e.g.,
>>
>> select sum(columnfp1), sum(colmnfp2) from table1;
>>
>> Do this on both master and slave. Should point out that if you
>> choose an index with numeric value it will be much faster.
>>
> When you have to scan the whole table, why will using the index > will be faster?
>>
>> Bob B
>>
>> ----- Original Message ----
>> From: Andrew Brosnan <andrew@broscom.com>
>> To: Paul Sindelar <paul.lists@mnwebhost.net>
>> Cc: replication@lists.mysql.com
>> Sent: Saturday, July 14, 2007 6:14:55 PM
>> Subject: Re: Verifing Data Integrity
>>
>> On 7/14/07 at 12:18 PM, paul.lists@mnwebhost.net (Paul Sindelar)
>> wrote:
>>
>>
>>> Does anyone know a reliable/efficient way of thoroughly verifying
>>> the integrity of a slave?
>>>
>>
>> Would this be done on a routine basis? I think it's more realistic
>> to do
>> routine sanity checks - perhaps you already do. What I do is check
>> for
>> same number of records on master and slave, thoroughly verify
>> *some* of
>> the data by checking random rows, compare file sizes, etc. I can't
>> imagine going through bit by bit without suspecting a problem. I
>> think
>> I'd be more likely to reset the slave with a new snapshot of the
>> masters
>> data. :-)
>>
>> Regards,
>> Andrew
>>
>>
>> --
>> MySQL Replication Mailing List
>> For list archives: http://lists.mysql.com/replication
>> To unsubscribe: http://lists.mysql.com/replication?
>> unsub=robertcb@yahoo.com
>>
>>
>>
>>
>>
>>
>>
>> _____________________________________________________________________
>> _______________
>> Park yourself in front of a world of choices in alternative
>> vehicles. Visit the Yahoo! Auto Green Center.
>> http://autos.yahoo.com/green_center/
>>
>
Robert Bankay -AST:7731^29u18e3
robertcb-1@comcast.net
Received on Sun Jul 15 20:16:33 2007
This archive was generated by hypermail 2.1.8 : Thu Aug 02 2007 - 01:57:07 EDT
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