basic tlog question

whenever a transaction or a SQL statement executes, do the changes get
written to the log file first ? I know they do, but are they also in
memory.. I understand the part where dirty pages are written to disk.. at
checkpoints or lazy writers or thru worker threads...what im a bit confused
is when it talks about writing to disk, is it referring to the data files on
disk or the log files on disk..
Can someone just give me a 2 to 3 liner on the initial part before the data
actually gets written to the disk i.e. disk that contains the data files ?
Yes, the log records are written to memory too, to an area called 'log
cache', and SQL Server has a logic to make sure these cached log records are
written to log files, before the associated dirty pages are written to disk.
Vyas, MVP (SQL Server)
http://vyaskn.tripod.com/
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:e3WwGOvaEHA.3524@.TK2MSFTNGP12.phx.gbl...
> whenever a transaction or a SQL statement executes, do the changes get
> written to the log file first ? I know they do, but are they also in
> memory.. I understand the part where dirty pages are written to disk.. at
> checkpoints or lazy writers or thru worker threads...what im a bit
confused
> is when it talks about writing to disk, is it referring to the data files
on
> disk or the log files on disk..
> Can someone just give me a 2 to 3 liner on the initial part before the
data
> actually gets written to the disk i.e. disk that contains the data files ?
>