Subject Re: [Firebird-Architect] Re: Some benchmarks about 'Order by' - temporary
Author Adriano dos Santos Fernandes
Vlad Horsun wrote:
>> When the set to be sorted is larger than can be handled in a memory
>> only sort, does it make sense to write the data to a temporary file
>> and perform a tag sort on the key values using the offset into that
>> file of the required data as the tag?
> This is what i wrote yesterday ;)
Don't this mean, more or less, in practice, as don't merge runs?

>> That would eliminate all the
>> page cache issues - and avoid churning the cache for other threads -
>> while reducing the size of the data to be sorted. The temporary file
>> would be written and read serially - relatively fast for a hard disk
>> operation.
> Written - yes, read - no.