Fix table_rewrite event trigger for ALTER TYPE/SET DATA TYPE CASCADE

When a composite type being used in a typed table is modified by way
of ALTER TYPE, a table rewrite occurs appearing to come from ALTER TYPE.
The existing event_trigger.c code was unable to cope with that
and raised a spurious error.  The fix is just to accept that command
tag for the event, and document this properly.

Noted while fooling with deparsing of DDL commands.  This appears to be
an oversight in commit 618c9430a.

Thanks to Mark Wong for documentation wording help.

diff --git a/doc/src/sgml/event-trigger.sgml b/doc/src/sgml/event-trigger.sgml
index 04353eac3d76c0ff6e15421f12b652384e557c35..f151eb73754f1998367149a1ed377c7131d5e3ce 100644 (file)
--- a/doc/src/sgml/event-trigger.sgml
+++ b/doc/src/sgml/event-trigger.sgml
@@ -68,12 +68,11 @@
 
    <para>
     The <literal>table_rewrite</> event occurs just before a table is
-    rewritten by the command <literal>ALTER TABLE</literal>. While other
+    rewritten by some actions of the commands <literal>ALTER TABLE</> and
+    <literal>ALTER TYPE</>.  While other
     control statements are available to rewrite a table,
     like <literal>CLUSTER</literal> and <literal>VACUUM</literal>,
-    the <literal>table_rewrite</> event is currently only triggered by
-    the <literal>ALTER TABLE</literal> command, and only when that command
-    attempts to rewrite the table.
+    the <literal>table_rewrite</> event is not triggered by them.
    </para>
 
    <para>
@@ -318,7 +317,7 @@
         <entry align="center"><literal>X</literal></entry>
         <entry align="center"><literal>X</literal></entry>
         <entry align="center"><literal>-</literal></entry>
-        <entry align="center"><literal>-</literal></entry>
+        <entry align="center"><literal>X</literal></entry>
         <entry align="center"></entry>
        </row>
        <row>

diff --git a/src/backend/commands/event_trigger.c b/src/backend/commands/event_trigger.c
index dcf5b987477a5fafacf2c559fcd7e0e472eb09af..deeb8dcfaf164821eb40a6af77b4a3054f85a457 100644 (file)
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -326,7 +326,8 @@ validate_table_rewrite_tags(const char *filtervar, List *taglist)
 static event_trigger_command_tag_check_result
 check_table_rewrite_ddl_tag(const char *tag)
 {
-       if (pg_strcasecmp(tag, "ALTER TABLE") == 0)
+       if (pg_strcasecmp(tag, "ALTER TABLE") == 0 ||
+               pg_strcasecmp(tag, "ALTER TYPE") == 0)
                return EVENT_TRIGGER_COMMAND_TAG_OK;
 
        return EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED;

diff --git a/src/test/regress/expected/event_trigger.out b/src/test/regress/expected/event_trigger.out
index 2095794576675c515bd20a96561763536d6becf8..8462fbff1c185b5a59d7c14724116425f8ad70f0 100644 (file)
--- a/src/test/regress/expected/event_trigger.out
+++ b/src/test/regress/expected/event_trigger.out
@@ -370,6 +370,17 @@ alter table rewriteme
 NOTICE:  Table 'rewriteme' is being rewritten (reason = 6)
 -- shouldn't trigger a table_rewrite event
 alter table rewriteme alter column foo type numeric(12,4);
+-- typed tables are rewritten when their type changes
+create type rewritetype as (a int);
+create table rewritemetoo1 of rewritetype;
+create table rewritemetoo2 of rewritetype;
+alter type rewritetype alter attribute a type text cascade;
+NOTICE:  Table 'rewritemetoo1' is being rewritten (reason = 4)
+NOTICE:  Table 'rewritemetoo2' is being rewritten (reason = 4)
+-- but this doesn't work
+create table rewritemetoo3 (a rewritetype);
+alter type rewritetype alter attribute a type varchar cascade;
+ERROR:  cannot alter type "rewritetype" because column "rewritemetoo3.a" uses it
 drop table rewriteme;
 drop event trigger no_rewrite_allowed;
 drop function test_evtrig_no_rewrite();

diff --git a/src/test/regress/sql/event_trigger.sql b/src/test/regress/sql/event_trigger.sql
index c6e47ed856eb7046ed57a68d6cbd2f7ffeae9726..4baad80b1df6b3c891aae097c19aee3fa025567d 100644 (file)
--- a/src/test/regress/sql/event_trigger.sql
+++ b/src/test/regress/sql/event_trigger.sql
@@ -276,6 +276,16 @@ alter table rewriteme
 -- shouldn't trigger a table_rewrite event
 alter table rewriteme alter column foo type numeric(12,4);
 
+-- typed tables are rewritten when their type changes
+create type rewritetype as (a int);
+create table rewritemetoo1 of rewritetype;
+create table rewritemetoo2 of rewritetype;
+alter type rewritetype alter attribute a type text cascade;
+
+-- but this doesn't work
+create table rewritemetoo3 (a rewritetype);
+alter type rewritetype alter attribute a type varchar cascade;
+
 drop table rewriteme;
 drop event trigger no_rewrite_allowed;
 drop function test_evtrig_no_rewrite();