database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Avoid index rebuild for no-rewrite ALTER TABLE .. ALTER TYPE.

Browse Source 
Noah Misch.  Review and minor cosmetic changes by me.
This commit is contained in:
Robert Haas
2011-07-18 11:02:48 -04:00
parent 8f8a273c4d
commit 367bc426a1
20 changed files with 348 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
doc/src/sgml/xindex.sgml
View File

@ -834,8 +834,10 @@ ALTER OPERATOR FAMILY integer_ops USING btree ADD
<para>
In a B-tree operator family, all the operators in the family must sort
compatibly, meaning that the transitive laws hold across all the data types
supported by the family: <quote>if A = B and B = C, then A =
C</>, and <quote>if A &lt; B and B &lt; C, then A &lt; C</>. For each
supported by the family: <quote>if A = B and B = C, then A = C</>,
and <quote>if A &lt; B and B &lt; C, then A &lt; C</>. Moreover, implicit
or binary coercion casts between types represented in the operator family
must not change the associated sort ordering. For each
operator in the family there must be a support function having the same
two input data types as the operator. It is recommended that a family be
complete, i.e., for each combination of data types, all operators are
@ -851,6 +853,9 @@ ALTER OPERATOR FAMILY integer_ops USING btree ADD
by the family's equality operators, even when the values are of different
types. This is usually difficult to accomplish when the types have
different physical representations, but it can be done in some cases.
Furthermore, casting a value from one data type represented in the operator
family to another data type also represented in the operator family via
an implicit or binary coercion cast must not change the computed hash value.
Notice that there is only one support function per data type, not one
per equality operator. It is recommended that a family be complete, i.e.,
provide an equality operator for each combination of data types.