Three patches for you today, all committed by Robert Hass:

• On 7th of February, patch:

  Add a transform function for numeric typmod coercisions.
   
  This enables ALTER TABLE to skip table and index rebuilds when a column
  is changed to an unconstrained numeric, or when the scale is unchanged
  and the precision does not decrease.
   
  Noah Misch, with a few stylistic changes and a fix for an OID
  collision by me.

• also on 7th, patch:

  Add a transform function for varbit typmod coercisions.
   
  This enables ALTER TABLE to skip table and index rebuilds when the
  new type is unconstraint varbit, or when the allowable number of bits
  is not decreasing.
   
  Noah Misch, with review and a fix for an OID collision by me.

• and a day later final patch:

  Add transform functions for various temporal typmod coercisions.
   
  This enables ALTER TABLE to skip table and index rebuilds in some cases.
   
  Noah Misch, with trivial changes by me.

Continue reading Waiting for 9.2 – More rewrite-less ALTER TABLE ALTER TYPEs