On 4/6/15 12:29 PM, k...@rice.edu wrote:
On Mon, Apr 06, 2015 at 12:07:47PM -0500, Jim Nasby wrote:
...
As I understand it, the goal here is to prevent huge amounts of
periodic freeze work due to XID wraparound. I don't think we need
the Freeze state to accomplish that.
With a single bit per page in the Frozen Map, checking a 800GB table
would require reading a mere 100MB of FM. That's pretty tiny, and
largely accomplishes the goal.
Obviously it would be nice to eliminate even that 100MB read, but I
suggest you leave that for a 3rd patch. I think you'll find that
just getting the first 2 accomplished will be a significant amount
of work.
Hi,
I may have my math wrong, but 800GB ~ 100M pages or 12.5MB and not
100MB.
Doh! 8 bits per byte and all that...
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
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