Allow new values to be added to an existing enum type.

After much expenditure of effort, we've got this to the point where the
performance penalty is pretty minimal in typical cases.

Andrew Dunstan, reviewed by Brendan Jurd, Dean Rasheed, and Tom Lane

2 files changed, 237 insertions, 2 deletions

diff --git a/src/test/regress/expected/enum.out b/src/test/regress/expected/enum.out
index 56240c0e7a2..b1ba3f1fad3 100644
--- a/src/test/regress/expected/enum.out
+++ b/src/test/regress/expected/enum.out
@@ -25,6 +25,155 @@ ERROR:  invalid input value for enum rainbow: "mauve"
 LINE 1: SELECT 'mauve'::rainbow;
                ^
 --
+-- adding new values
+--
+CREATE TYPE planets AS ENUM ( 'venus', 'earth', 'mars' );
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+ enumlabel | enumsortorder 
+-----------+---------------
+ venus     |             1
+ earth     |             2
+ mars      |             3
+(3 rows)
+
+ALTER TYPE planets ADD 'uranus';
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+ enumlabel | enumsortorder 
+-----------+---------------
+ venus     |             1
+ earth     |             2
+ mars      |             3
+ uranus    |             4
+(4 rows)
+
+ALTER TYPE planets ADD 'mercury' BEFORE 'venus';
+ALTER TYPE planets ADD 'saturn' BEFORE 'uranus';
+ALTER TYPE planets ADD 'jupiter' AFTER 'mars';
+ALTER TYPE planets ADD 'neptune' AFTER 'uranus';
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+ enumlabel | enumsortorder 
+-----------+---------------
+ mercury   |             0
+ venus     |             1
+ earth     |             2
+ mars      |             3
+ jupiter   |          3.25
+ saturn    |           3.5
+ uranus    |             4
+ neptune   |             5
+(8 rows)
+
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY enumlabel::planets;
+ enumlabel | enumsortorder 
+-----------+---------------
+ mercury   |             0
+ venus     |             1
+ earth     |             2
+ mars      |             3
+ jupiter   |          3.25
+ saturn    |           3.5
+ uranus    |             4
+ neptune   |             5
+(8 rows)
+
+-- errors for adding labels
+ALTER TYPE planets ADD
+  'plutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutopluto';
+ERROR:  invalid enum label "plutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutopluto"
+DETAIL:  Labels must be 63 characters or less.
+ALTER TYPE planets ADD 'pluto' AFTER 'zeus';
+ERROR:  "zeus" is not an existing enum label
+--
+-- Test inserting so many values that we have to renumber
+--
+create type insenum as enum ('L1', 'L2');
+alter type insenum add 'i1' before 'L2';
+alter type insenum add 'i2' before 'L2';
+alter type insenum add 'i3' before 'L2';
+alter type insenum add 'i4' before 'L2';
+alter type insenum add 'i5' before 'L2';
+alter type insenum add 'i6' before 'L2';
+alter type insenum add 'i7' before 'L2';
+alter type insenum add 'i8' before 'L2';
+alter type insenum add 'i9' before 'L2';
+alter type insenum add 'i10' before 'L2';
+alter type insenum add 'i11' before 'L2';
+alter type insenum add 'i12' before 'L2';
+alter type insenum add 'i13' before 'L2';
+alter type insenum add 'i14' before 'L2';
+alter type insenum add 'i15' before 'L2';
+alter type insenum add 'i16' before 'L2';
+alter type insenum add 'i17' before 'L2';
+alter type insenum add 'i18' before 'L2';
+alter type insenum add 'i19' before 'L2';
+alter type insenum add 'i20' before 'L2';
+alter type insenum add 'i21' before 'L2';
+alter type insenum add 'i22' before 'L2';
+alter type insenum add 'i23' before 'L2';
+alter type insenum add 'i24' before 'L2';
+alter type insenum add 'i25' before 'L2';
+alter type insenum add 'i26' before 'L2';
+alter type insenum add 'i27' before 'L2';
+alter type insenum add 'i28' before 'L2';
+alter type insenum add 'i29' before 'L2';
+alter type insenum add 'i30' before 'L2';
+-- The exact values of enumsortorder will now depend on the local properties
+-- of float4, but in any reasonable implementation we should get at least
+-- 20 splits before having to renumber; so only hide values > 20.
+SELECT enumlabel,
+       case when enumsortorder > 20 then null else enumsortorder end as so
+FROM pg_enum
+WHERE enumtypid = 'insenum'::regtype
+ORDER BY enumsortorder;
+ enumlabel | so 
+-----------+----
+ L1        |  1
+ i1        |  2
+ i2        |  3
+ i3        |  4
+ i4        |  5
+ i5        |  6
+ i6        |  7
+ i7        |  8
+ i8        |  9
+ i9        | 10
+ i10       | 11
+ i11       | 12
+ i12       | 13
+ i13       | 14
+ i14       | 15
+ i15       | 16
+ i16       | 17
+ i17       | 18
+ i18       | 19
+ i19       | 20
+ i20       |   
+ i21       |   
+ i22       |   
+ i23       |   
+ i24       |   
+ i25       |   
+ i26       |   
+ i27       |   
+ i28       |   
+ i29       |   
+ i30       |   
+ L2        |   
+(32 rows)
+
+--
 -- Basic table creation, row selection
 --
 CREATE TABLE enumtest (col rainbow);
@@ -403,7 +552,7 @@ SELECT COUNT(*) FROM pg_type WHERE typname = 'rainbow';
 
 SELECT * FROM pg_enum WHERE NOT EXISTS
   (SELECT 1 FROM pg_type WHERE pg_type.oid = enumtypid);
- enumtypid | enumlabel 
------------+-----------
+ enumtypid | enumsortorder | enumlabel 
+-----------+---------------+-----------
 (0 rows)
 
diff --git a/src/test/regress/sql/enum.sql b/src/test/regress/sql/enum.sql
index 387e8e72ed8..70bf8c5f1ba 100644
--- a/src/test/regress/sql/enum.sql
+++ b/src/test/regress/sql/enum.sql
@@ -16,6 +16,92 @@ SELECT 'red'::rainbow;
 SELECT 'mauve'::rainbow;
 
 --
+-- adding new values
+--
+
+CREATE TYPE planets AS ENUM ( 'venus', 'earth', 'mars' );
+
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+
+ALTER TYPE planets ADD 'uranus';
+
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+
+ALTER TYPE planets ADD 'mercury' BEFORE 'venus';
+ALTER TYPE planets ADD 'saturn' BEFORE 'uranus';
+ALTER TYPE planets ADD 'jupiter' AFTER 'mars';
+ALTER TYPE planets ADD 'neptune' AFTER 'uranus';
+
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY 2;
+
+SELECT enumlabel, enumsortorder
+FROM pg_enum
+WHERE enumtypid = 'planets'::regtype
+ORDER BY enumlabel::planets;
+
+-- errors for adding labels
+ALTER TYPE planets ADD
+  'plutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutoplutopluto';
+
+ALTER TYPE planets ADD 'pluto' AFTER 'zeus';
+
+--
+-- Test inserting so many values that we have to renumber
+--
+
+create type insenum as enum ('L1', 'L2');
+
+alter type insenum add 'i1' before 'L2';
+alter type insenum add 'i2' before 'L2';
+alter type insenum add 'i3' before 'L2';
+alter type insenum add 'i4' before 'L2';
+alter type insenum add 'i5' before 'L2';
+alter type insenum add 'i6' before 'L2';
+alter type insenum add 'i7' before 'L2';
+alter type insenum add 'i8' before 'L2';
+alter type insenum add 'i9' before 'L2';
+alter type insenum add 'i10' before 'L2';
+alter type insenum add 'i11' before 'L2';
+alter type insenum add 'i12' before 'L2';
+alter type insenum add 'i13' before 'L2';
+alter type insenum add 'i14' before 'L2';
+alter type insenum add 'i15' before 'L2';
+alter type insenum add 'i16' before 'L2';
+alter type insenum add 'i17' before 'L2';
+alter type insenum add 'i18' before 'L2';
+alter type insenum add 'i19' before 'L2';
+alter type insenum add 'i20' before 'L2';
+alter type insenum add 'i21' before 'L2';
+alter type insenum add 'i22' before 'L2';
+alter type insenum add 'i23' before 'L2';
+alter type insenum add 'i24' before 'L2';
+alter type insenum add 'i25' before 'L2';
+alter type insenum add 'i26' before 'L2';
+alter type insenum add 'i27' before 'L2';
+alter type insenum add 'i28' before 'L2';
+alter type insenum add 'i29' before 'L2';
+alter type insenum add 'i30' before 'L2';
+
+-- The exact values of enumsortorder will now depend on the local properties
+-- of float4, but in any reasonable implementation we should get at least
+-- 20 splits before having to renumber; so only hide values > 20.
+
+SELECT enumlabel,
+       case when enumsortorder > 20 then null else enumsortorder end as so
+FROM pg_enum
+WHERE enumtypid = 'insenum'::regtype
+ORDER BY enumsortorder;
+
+--
 -- Basic table creation, row selection
 --
 CREATE TABLE enumtest (col rainbow);