Hi,
Simon Riggs wrote:
On Fri, 2008-01-04 at 13:06 -0500, Andrew Sullivan wrote:
On Fri, Jan 04, 2008 at 01:29:55PM +0100, Markus Schiltknecht wrote:
Agreed. Just a minor note: I find "marked read-only" too strong, as it
implies an impossibility to write. I propose speaking about mostly-read
segments, or optimized for reading or similar.
Hm.. yeah, after rereading, I realize that I've mixed up states no. 2
and 3 here, sorry.
I do want some segments to be _marked_ read-only: I want attempted writes to
them to _fail_.
Well, I can see use cases for marking tuples or complete relations as
read only. But segments?
I'm still puzzled about how a DBA is expected to figure out which
segments to mark. Simon, are you assuming we are going to pass on
segment numbers to the DBA one day?
If not, a more user friendly command like "MARK READ ONLY WHERE date <=
2006" would have to move tuples around between segments, so as to be
able to satisfy the split point exactly, right?
I think Markus thought that we would mark them read only automatically,
which was not my intention. I believe its possible to have this in a way
that will make you both happy. Some more explanation:
There would be three different states for a segment:
1. read write
2. "optimized for reading", as Markus says it
3. marked read only by explicit command
Thanks for clarification.
Regards
Markus
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