Hi.
On Wed 2002-06-05 at 14:25:30 -0400, [EMAIL PROTECTED] wrote:
> Hi all,
>
> Does anyone have any numbers on the speed of MySql replication? I am
> concerned
> with the transfer of up to 10 gigabytes to a master db... what state are
> the slaves in during the replication catch up time? Is the delay primarily
> related to the network bandwidth? I am assuming that all the SQL statements
> are processed on the master and the changes are what get propagated... is
> that correct?
Not completely. The master logs all queries which change the database
(mainly INSERT and DELETE) and will send them to the slave on request.
AFAIK, the slave will execute the queries as if they were coming from
an usual client (with a few exceptions), so it does the processing
again. But that should not impose a major performance issue.
I am not sure what the transfer method for initial synchronisation is,
but I presume, some parsing is involved, too.
Network speed usually won't be a major bottleneck, except if you are
inserting really large records[1] or the connection to the database is
slow.
In my experience disk speed will be your main issue.
Bye,
Benjamin.
[1] I.e. in a production database of ours the average INSERT/UPDATE
size of the most common query is about 600 bytes (user postings).
You would be able to transmit about 18.000 INSERTs over a standard
100MBit line.
Of course you wouldn't be able to transfer those 10GB faster than
10GB/100MBit =~ 1000 secs =~ 17 mins on that line (in fact, you
are lucky, if you get full transfer speed), but I have yet to see
a standard (=non-high-end) hardware which could do so much inserts
on average.
--
[EMAIL PROTECTED]
---------------------------------------------------------------------
Before posting, please check:
http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
To request this thread, e-mail <[EMAIL PROTECTED]>
To unsubscribe, e-mail <[EMAIL PROTECTED]>
Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
