Migration COPY to new framework.

This implies several behaviour changes:
- COPY is now transactional
- failure to compute stats for append partitioned tables is an error

src/include/distributed/master_protocol.h

@@ -66,7 +66,7 @@
 #define CREATE_SCHEMA_COMMAND "CREATE SCHEMA IF NOT EXISTS %s"
 #define CREATE_EMPTY_SHARD_QUERY "SELECT master_create_empty_shard('%s')"
 #define FINALIZED_SHARD_PLACEMENTS_QUERY \
-	"SELECT nodename, nodeport FROM pg_dist_shard_placement WHERE shardstate = 1 AND shardid = %ld"
+	"SELECT placementid, nodename, nodeport FROM pg_dist_shard_placement WHERE shardstate = 1 AND shardid = %ld"
 #define UPDATE_SHARD_STATISTICS_QUERY \
 	"SELECT master_update_shard_statistics(%ld)"
 #define PARTITION_METHOD_QUERY "SELECT part_method FROM master_get_table_metadata('%s');"

src/test/regress/expected/multi_modifying_xacts.out

@@ -160,31 +160,27 @@ INSERT INTO labs VALUES (6, 'Bell Labs');
 SELECT count(*) FROM researchers WHERE lab_id = 6;
 ERROR:  cannot open new connections after the first modification command within a transaction
 ABORT;
--- COPY can't happen second,
+-- Check COPY can happen after INSERT
 BEGIN;
 INSERT INTO labs VALUES (6, 'Bell Labs');
 \copy labs from stdin delimiter ','
-ERROR:  distributed copy operations must not appear in transaction blocks containing other distributed modifications
-CONTEXT:  COPY labs, line 1: "10,Weyland-Yutani"
 COMMIT;
--- though it will work if before any modifications
+-- Check COPY can happen before INSERT
 BEGIN;
 \copy labs from stdin delimiter ','
 SELECT name FROM labs WHERE id = 10;
       name      
 ----------------
  Weyland-Yutani
-(1 row)
+ Weyland-Yutani
+(2 rows)
 
 INSERT INTO labs VALUES (6, 'Bell Labs');
-ERROR:  cannot open new connections after the first modification command within a transaction
 COMMIT;
--- but a double-copy isn't allowed (the first will persist)
+-- Two COPYs are also ok
 BEGIN;
 \copy labs from stdin delimiter ','
 \copy labs from stdin delimiter ','
-ERROR:  distributed copy operations must not appear in transaction blocks containing other distributed modifications
-CONTEXT:  COPY labs, line 1: "12,fsociety"
 COMMIT;
 SELECT name FROM labs WHERE id = 11;
       name      
@@ -192,13 +188,12 @@ SELECT name FROM labs WHERE id = 11;
  Planet Express
 (1 row)
 
--- finally, ALTER and copy aren't compatible
+-- finally, check ALTER and copy are compatible
 BEGIN;
 ALTER TABLE labs ADD COLUMN motto2 text;
 \copy labs from stdin delimiter ','
-ERROR:  distributed copy operations must not appear in transaction blocks containing other distributed modifications
-CONTEXT:  COPY labs, line 1: "12,fsociety,lol"
 COMMIT;
+ALTER TABLE labs DROP COLUMN motto2;
 -- but the DDL should correctly roll back
 \d labs
      Table "public.labs"
@@ -207,30 +202,33 @@ COMMIT;
  id     | bigint | not null
  name   | text   | not null
 
-SELECT * FROM labs WHERE id = 12;
- id | name 
-----+------
-(0 rows)
-
--- and if the copy is before the ALTER...
-BEGIN;
-\copy labs from stdin delimiter ','
-ALTER TABLE labs ADD COLUMN motto3 text;
-ERROR:  distributed DDL commands must not appear within transaction blocks containing data modifications
-COMMIT;
--- the DDL fails, but copy persists
-\d labs
-     Table "public.labs"
- Column |  Type  | Modifiers 
---------+--------+-----------
- id     | bigint | not null
- name   | text   | not null
-
 SELECT * FROM labs WHERE id = 12;
  id |   name   
 ----+----------
  12 | fsociety
-(1 row)
+ 12 | fsociety
+(2 rows)
+
+-- and if the copy is before the ALTER...
+BEGIN;
+\copy labs from stdin delimiter ','
+ALTER TABLE labs ADD COLUMN motto3 text;
+ERROR:  distributed DDL commands must not appear within transaction blocks containing data modifications
+COMMIT;
+-- the DDL fails, and copy does not persist
+\d labs
+     Table "public.labs"
+ Column |  Type  | Modifiers 
+--------+--------+-----------
+ id     | bigint | not null
+ name   | text   | not null
+
+SELECT * FROM labs WHERE id = 12;
+ id |   name   
+----+----------
+ 12 | fsociety
+ 12 | fsociety
+(2 rows)
 
 -- now, for some special failures...
 CREATE TABLE objects (

src/test/regress/output/multi_copy.source

@@ -702,8 +702,4 @@ SELECT master_create_distributed_table('composite_partition_column_table', 'comp
 WARNING:  function min(number_pack) does not exist
 HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 CONTEXT:  while executing command on localhost:57637
-WARNING:  function min(number_pack) does not exist
+ERROR:  failure on connection marked as essential: localhost:57637
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
-CONTEXT:  while executing command on localhost:57638
-WARNING:  could not get statistics for shard public.composite_partition_column_table_560164
-DETAIL:  Setting shard statistics to NULL

src/test/regress/sql/multi_modifying_xacts.sql

@@ -131,7 +131,7 @@ INSERT INTO labs VALUES (6, 'Bell Labs');
 SELECT count(*) FROM researchers WHERE lab_id = 6;
 ABORT;
 
--- COPY can't happen second,
+-- Check COPY can happen after INSERT
 BEGIN;
 INSERT INTO labs VALUES (6, 'Bell Labs');
 \copy labs from stdin delimiter ','
@@ -139,7 +139,7 @@ INSERT INTO labs VALUES (6, 'Bell Labs');
 \.
 COMMIT;
 
--- though it will work if before any modifications
+-- Check COPY can happen before INSERT
 BEGIN;
 \copy labs from stdin delimiter ','
 10,Weyland-Yutani
@@ -148,7 +148,7 @@ SELECT name FROM labs WHERE id = 10;
 INSERT INTO labs VALUES (6, 'Bell Labs');
 COMMIT;
 
--- but a double-copy isn't allowed (the first will persist)
+-- Two COPYs are also ok
 BEGIN;
 \copy labs from stdin delimiter ','
 11,Planet Express
@@ -160,13 +160,14 @@ COMMIT;
 
 SELECT name FROM labs WHERE id = 11;
 
--- finally, ALTER and copy aren't compatible
+-- finally, check ALTER and copy are compatible
 BEGIN;
 ALTER TABLE labs ADD COLUMN motto2 text;
 \copy labs from stdin delimiter ','
 12,fsociety,lol
 \.
 COMMIT;
+ALTER TABLE labs DROP COLUMN motto2;
 
 -- but the DDL should correctly roll back
 \d labs
@@ -180,7 +181,7 @@ BEGIN;
 ALTER TABLE labs ADD COLUMN motto3 text;
 COMMIT;
 
--- the DDL fails, but copy persists
+-- the DDL fails, and copy does not persist
 \d labs
 SELECT * FROM labs WHERE id = 12;