Excellent. Thank you for the information.
Keith
Jim Starkey wrote:
> Keith Murphy wrote:
>> Hello everyone,
>>
>> I have a quick question. Testing seems to indicate that Falcon keeps
>> accurate stats on the number of rows in a table. It appears similar
>> to the way MyISAM tables work. This can shown by running a 'SHOW
>> TABLE STATUS' command and comparing the number of rows with the
>> SELECT COUNT(*) command. Am I correct in this? Or have I not done
>> enough tests?
>>
>> Also, SELECT COUNT(*) appears to return a number of rows much quick
>> than a similar command on InnoDB tables. Again..similar to MyISAM. Am
>> I accurate in this?
>>
> The row count is Falcon is not guaranteed accurate and should not be
> depended upon. Falcon does a good faith effort to track table
> cardinalities, but number of records visible to any given transaction
> is not necessarily the number of committed records in the table.
> Other transaction may have committed records that are not yet visible,
> and pending transactions have have insert records that will eventually
> be rolled back.
>
> Count(*) is accurate from a transaction's perspective, but will not
> include record insert -- even if committed -- by a concurrent
> transaction.
>
> The record could from SHOW TABLE STATUS is a good faith estimate,
> nothing more.
>
>
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