Flexible Freeze outline

gistfile1.txt

Specification:

BASIC VERSION

Config File:
   Series of time windows for "low traffic" points.
      e.g. "Sunday 1am-4am"
   Postgres connection info for 1 database
   vacuum settings
   min_freeze threshold (default 1,000,000)
   pause between freeze length (default 1 minute)

Actions:
   
1. Called by Cron every hour
2. Checks if it's already running.  If so, quits.
3. Checks if it's in a freeze time window.  If not, quits.
4. Gets list of unfrozen relations, sorted by oldest XID, minimum per config
5. Loops through relations one at a time:
   a. Checks if still in time window (if not, exits)
   b. Does VACUUM FREEZE with config settings
   c. Pauses per config
6. When it runs out of relations or time, exits.

Requirements
   Perl or Python
   PostgreSQL drivers
   Cron


ADVANCED VERSION

Same as basic version, except:

A. Supports multiple databases
B. Supports checks on system load, concurrent transactions, and wait status
   with thresholds for quitting if load is too high
C. Supports multiple threads for parallel freeezing
D. Kills running VACUUM at end of time window if still running.