Append shardId before escaping the table name

Fixes #550, fixes #545

If table name contains special characters, it needs to be escaped. However in some cases,
we escape table name before appending shardId, which causes syntax error in the queries
sent to worker nodes. With this change we now append shardId before escaping table names.

src/backend/distributed/commands/multi_copy.c

@@ -1078,14 +1078,20 @@ static StringInfo
 ConstructCopyStatement(CopyStmt *copyStatement, int64 shardId)
 {
 	StringInfo command = makeStringInfo();
-	char *qualifiedName = NULL;
 
-	qualifiedName = quote_qualified_identifier(copyStatement->relation->schemaname,
+	char *schemaName = copyStatement->relation->schemaname;
-											   copyStatement->relation->relname);
+	char *relationName = copyStatement->relation->relname;
 
-	appendStringInfo(command, "COPY %s_%ld ", qualifiedName, shardId);
+	char *shardName = pstrdup(relationName);
+	char *shardQualifiedName = NULL;
 
-	appendStringInfoString(command, "FROM STDIN WITH (FORMAT BINARY)");
+	AppendShardIdToName(&shardName, shardId);
+
+	shardQualifiedName = quote_qualified_identifier(schemaName, shardName);
+
+	appendStringInfo(command,
+					 "COPY %s FROM STDIN WITH (FORMAT BINARY)",
+					 shardQualifiedName);
 
 	return command;
 }

src/backend/distributed/master/master_stage_protocol.c

@@ -476,14 +476,14 @@ UpdateShardStatistics(int64 shardId)
 	shardQualifiedName = LoadShardAlias(relationId, shardId);
 	if (shardQualifiedName == NULL)
 	{
-		char *relationName = get_rel_name(relationId);
+		char *shardName = get_rel_name(relationId);
 
 		Oid schemaId = get_rel_namespace(relationId);
 		char *schemaName = get_namespace_name(schemaId);
 
-		shardQualifiedName = quote_qualified_identifier(schemaName, relationName);
+		AppendShardIdToName(&shardName, shardId);
 
-		AppendShardIdToName(&shardQualifiedName, shardId);
+		shardQualifiedName = quote_qualified_identifier(schemaName, shardName);
 	}
 
 	shardPlacementList = FinalizedShardPlacementList(shardId);

src/test/regress/input/multi_copy.source

@@ -378,3 +378,39 @@ COPY append.customer_copy FROM '@abs_srcdir@/data/customer.2.data' with (delimit
 
 -- Test the content of the table
 SELECT min(c_custkey), max(c_custkey), avg(c_acctbal), count(*) FROM append.customer_copy;
+
+-- Test with table name which contains special character
+CREATE TABLE "customer_with_special_\\_character"(
+        c_custkey integer,
+        c_name varchar(25) not null);
+
+SELECT master_create_distributed_table('"customer_with_special_\\_character"', 'c_custkey', 'hash');
+
+SELECT master_create_worker_shards('"customer_with_special_\\_character"', 4, 1);
+
+COPY "customer_with_special_\\_character" (c_custkey, c_name) FROM STDIN
+WITH (FORMAT 'csv');
+1,customer1
+2,customer2
+\.
+
+-- Confirm that data was copied
+SELECT count(*) FROM "customer_with_special_\\_character";
+
+-- Test with table name which starts with number
+CREATE TABLE "1_customer"(
+        c_custkey integer,
+        c_name varchar(25) not null);
+
+SELECT master_create_distributed_table('"1_customer"', 'c_custkey', 'hash');
+
+SELECT master_create_worker_shards('"1_customer"', 4, 1);
+
+COPY "1_customer" (c_custkey, c_name) FROM STDIN
+WITH (FORMAT 'csv');
+1,customer1
+2,customer2
+\.
+
+-- Confirm that data was copied
+SELECT count(*) FROM "1_customer";

src/test/regress/output/multi_copy.source

@@ -500,3 +500,53 @@ SELECT min(c_custkey), max(c_custkey), avg(c_acctbal), count(*) FROM append.cust
    1 | 7000 | 4443.8028800000000000 |  2000
 (1 row)
 
+-- Test with table name which contains special character
+CREATE TABLE "customer_with_special_\\_character"(
+        c_custkey integer,
+        c_name varchar(25) not null);
+SELECT master_create_distributed_table('"customer_with_special_\\_character"', 'c_custkey', 'hash');
+ master_create_distributed_table 
+---------------------------------
+ 
+(1 row)
+
+SELECT master_create_worker_shards('"customer_with_special_\\_character"', 4, 1);
+ master_create_worker_shards 
+-----------------------------
+ 
+(1 row)
+
+COPY "customer_with_special_\\_character" (c_custkey, c_name) FROM STDIN
+WITH (FORMAT 'csv');
+-- Confirm that data was copied
+SELECT count(*) FROM "customer_with_special_\\_character";
+ count 
+-------
+     2
+(1 row)
+
+-- Test with table name which starts with number
+CREATE TABLE "1_customer"(
+        c_custkey integer,
+        c_name varchar(25) not null);
+SELECT master_create_distributed_table('"1_customer"', 'c_custkey', 'hash');
+ master_create_distributed_table 
+---------------------------------
+ 
+(1 row)
+
+SELECT master_create_worker_shards('"1_customer"', 4, 1);
+ master_create_worker_shards 
+-----------------------------
+ 
+(1 row)
+
+COPY "1_customer" (c_custkey, c_name) FROM STDIN
+WITH (FORMAT 'csv');
+-- Confirm that data was copied
+SELECT count(*) FROM "1_customer";
+ count 
+-------
+     2
+(1 row)
+