Doc: in v12 release notes, explain how to replace uses of consrc and adsrc.

tglsfdc · tglsfdc · commit d61e7f174db9 · 2019-11-15T12:31:53.000-05:00
While you can find that info if you drill down far enough, it seems more helpful to put something right in the compatibility notes. Per a question from Ivan Sergio Borgonovo. Discussion: https://postgr.es/m/a6359855-2a5e-a56c-ebba-4ea46a1f0ebe@webthatworks.it
diff --git a/doc/src/sgml/release-12.sgml b/doc/src/sgml/release-12.sgml
@@ -1590,6 +1590,16 @@ Author: Peter Eisentraut <peter_e@gmx.net>
       linkend="catalog-pg-constraint"><structname>pg_constraint</structname></link>.<structfield>consrc</structfield>
       column (Peter Eisentraut)
      </para>
+
+     <para>
+      This column has been deprecated for a long time, because it did not
+      update in response to other catalog changes (such as column renamings).
+      The recommended way to get a text version of a check constraint's
+      expression from <structname>pg_constraint</structname>
+      is <literal>pg_get_expr(conbin, conrelid)</literal>.
+      <function>pg_get_constraintdef()</function> is also a useful
+      alternative.
+     </para>
     </listitem>
 
     <listitem>
@@ -1603,6 +1613,14 @@ Author: Peter Eisentraut <peter_e@gmx.net>
       linkend="catalog-pg-attrdef"><structname>pg_attrdef</structname></link>.<structfield>adsrc</structfield>
       column (Peter Eisentraut)
      </para>
+
+     <para>
+      This column has been deprecated for a long time, because it did not
+      update in response to other catalog changes (such as column renamings).
+      The recommended way to get a text version of a default-value expression
+      from <structname>pg_attrdef</structname> is <literal>pg_get_expr(adbin,
+      adrelid)</literal>.
+     </para>
     </listitem>
 
     <listitem>
