COPY FROM deparse more complete, PG_SHARDMAN macro.

Now column names, FORCE NULL and FORCE NOT NULL are deparsed too.
PG_SHARDMAN macro ensures this PG contains patches for Postgres.

Author: arssher

contrib/postgres_fdw/deparse.c

@@ -3176,33 +3176,89 @@ get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
 }
 
 /*
- * Deparse COPY FROM
+ * Deparse COPY FROM into given buf.
  */
 void
 deparseCopyFromSql(StringInfo buf, Relation rel, CopyState cstate,
 				   const char *dest_relname)
 {
+	ListCell *cur;
+
 	appendStringInfoString(buf, "COPY ");
 	if (dest_relname == NULL)
 		deparseRelation(buf, rel);
 	else
 		appendStringInfoString(buf, dest_relname);
-	appendStringInfoString(buf, " FROM STDIN WITH (");
 
-	/* TODO: deparse column names */
 	if (cstate->binary)
 	{
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("cannot copy to postgres_fdw table \"%s\" in binary format ",
-							RelationGetRelationName(rel))));
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot copy to postgres_fdw table \"%s\" in binary format ",
+						RelationGetRelationName(rel))));
+	}
+
+	/* deparse column names */
+	if (cstate->attnumlist != NIL)
+	{
+		bool first = true;
+
+		appendStringInfoString(buf, " (");
+		foreach(cur, cstate->attnumlist)
+		{
+			int attnum = lfirst_int(cur);
+			char *attname;
+
+			if (!first)
+				appendStringInfoString(buf, ", ");
+			first = false;
+
+			attname = get_relid_attribute_name(rel->rd_id, attnum);
+			appendStringInfoString(buf, quote_identifier(attname));
+		}
+		appendStringInfoString(buf, " )");
 	}
+
+	appendStringInfoString(buf, " FROM STDIN WITH (");
 	if (cstate->csv_mode)
 	{
 		appendStringInfoString(buf, " FORMAT csv ");
 		appendStringInfo(buf, ", QUOTE '%c'", *(cstate->quote));
 		appendStringInfo(buf, ", ESCAPE '%c'", *(cstate->escape));
-		/* TODO: force quote, force not null, force null */
+		if (cstate->force_notnull != NIL)
+		{
+			bool first = true;
+
+			appendStringInfoString(buf, " FORCE NOT NULL (");
+			foreach(cur, cstate->force_notnull)
+			{
+				char *attname = strVal(lfirst(cur));
+
+				if (!first)
+					appendStringInfoString(buf, ", ");
+				first = false;
+
+				appendStringInfoString(buf, quote_identifier(attname));
+			}
+			appendStringInfoString(buf, " )");
+		}
+		if (cstate->force_null != NIL)
+		{
+			bool first = true;
+
+			appendStringInfoString(buf, " FORCE NULL (");
+			foreach(cur, cstate->force_null)
+			{
+				char *attname = strVal(lfirst(cur));
+
+				if (!first)
+					appendStringInfoString(buf, ", ");
+				first = false;
+
+				appendStringInfoString(buf, quote_identifier(attname));
+			}
+			appendStringInfoString(buf, " )");
+		}
 	}
 	else
 	{

contrib/postgres_fdw/postgres_fdw.c

@@ -360,7 +360,7 @@ static void postgresGetForeignUpperPaths(PlannerInfo *root,
 static void postgresBeginForeignCopyFrom(EState *estate,
 										 ResultRelInfo *rinfo,
 										 CopyState cstate,
-										 const char *dest_relname);
+										 ResultRelInfo *parent_rinfo);
 static void postgresForeignNextCopyFrom(EState *estate,
 										ResultRelInfo *rinfo,
 										CopyState cstate);
@@ -5219,20 +5219,28 @@ postgres_fdw_exec(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
-/* Begin COPY FROM to foreign table */
+/*
+ * Begin COPY FROM to foreign table. Currently we do it in a bit perverted
+ * way: we redirect COPY FROM to parent table on foreign server, assuming it
+ * exists in public schema (as in shardman), and let it direct tuples to
+ * proper partitions. Otherwise we would have to modify logic of managing
+ * connections and keep many connections open to one server from one backend.
+ * This probably should not be used outside pg_shardman.
+ */
 static void
 postgresBeginForeignCopyFrom(EState *estate, ResultRelInfo *rinfo,
-							 CopyState cstate, const char *dest_relname)
+							 CopyState cstate, ResultRelInfo *parent_rinfo)
 {
 	Relation		rel = rinfo->ri_RelationDesc;
 	RangeTblEntry	*rte;
 	Oid				userid;
 	ForeignTable	*table;
 	UserMapping		*user;
 	StringInfoData 	sql;
-	PGconn	   *conn;
-	PGresult   *res;
-	bool *copy_from_started;
+	PGconn	   		*conn;
+	PGresult   		*res;
+	bool			*copy_from_started;
+	char 			*dest_relname;
 
 	/*
 	 * Identify which user to do the remote access as.  This should match what
@@ -5253,6 +5261,11 @@ postgresBeginForeignCopyFrom(EState *estate, ResultRelInfo *rinfo,
 		return;
 
 	/* deparse COPY stmt */
+	dest_relname = psprintf(
+		"public.%s", quote_identifier(RelationGetRelationName(
+										  parent_rinfo == NULL ?
+										  rinfo->ri_RelationDesc :
+										  parent_rinfo->ri_RelationDesc)));
 	initStringInfo(&sql);
 	deparseCopyFromSql(&sql, rel, cstate, dest_relname);
 
@@ -5327,4 +5340,4 @@ _PG_init(void)
 							 "Use repeatable read isilation error for remote transactions", NULL,
 							 &UseRepeatableRead, true, PGC_USERSET, 0, NULL,
 							 NULL, NULL);
-}
+}

src/include/foreign/fdwapi.h

@@ -163,7 +163,7 @@ typedef bool (*IsForeignScanParallelSafe_function) (PlannerInfo *root,
 typedef void (*BeginForeignCopyFrom_function) (EState *estate,
 											   ResultRelInfo *rinfo,
 											   CopyState cstate,
-											   const char *dest_relname);
+											   ResultRelInfo *parent_rinfo);
 /*
  * Currently we support only text and csv format and pass each row in
  * cstate->line_buf. We should also pass binary data and/or deformed tuple.

src/include/pg_config.h.in

@@ -753,6 +753,9 @@
 /* PostgreSQL version as a number */
 #undef PG_VERSION_NUM
 
+/* This version contains patches for pg_shardman */
+#define PG_SHARDMAN
+
 /* A string containing the version number, platform, and C compiler */
 #undef PG_VERSION_STR
 

src/include/pg_config.h.win32

@@ -565,6 +565,9 @@
 /* PostgreSQL version as a number */
 #define PG_VERSION_NUM 100000
 
+/* This version contains patches for pg_shardman */
+#define PG_SHARDMAN
+
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "postgresql"