1 files changed, 130 insertions, 21 deletions

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 98da9c54401..17f84d28a95 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -317,6 +317,7 @@ static void appendReloptionsArrayAH(PQExpBuffer buffer, const char *reloptions,
 static char *get_synchronized_snapshot(Archive *fout);
 static void setupDumpWorker(Archive *AHX);
 static TableInfo *getRootTableInfo(const TableInfo *tbinfo);
+static bool forcePartitionRootLoad(const TableInfo *tbinfo);
 
 
 int
@@ -2192,11 +2193,13 @@ dumpTableData_insert(Archive *fout, const void *dcontext)
 			insertStmt = createPQExpBuffer();
 
 			/*
-			 * When load-via-partition-root is set, get the root table name
-			 * for the partition table, so that we can reload data through the
-			 * root table.
+			 * When load-via-partition-root is set or forced, get the root
+			 * table name for the partition table, so that we can reload data
+			 * through the root table.
 			 */
-			if (dopt->load_via_partition_root && tbinfo->ispartition)
+			if (tbinfo->ispartition &&
+				(dopt->load_via_partition_root ||
+				 forcePartitionRootLoad(tbinfo)))
 				targettab = getRootTableInfo(tbinfo);
 			else
 				targettab = tbinfo;
@@ -2395,6 +2398,35 @@ getRootTableInfo(const TableInfo *tbinfo)
 }
 
 /*
+ * forcePartitionRootLoad
+ *     Check if we must force load_via_partition_root for this partition.
+ *
+ * This is required if any level of ancestral partitioned table has an
+ * unsafe partitioning scheme.
+ */
+static bool
+forcePartitionRootLoad(const TableInfo *tbinfo)
+{
+	TableInfo  *parentTbinfo;
+
+	Assert(tbinfo->ispartition);
+	Assert(tbinfo->numParents == 1);
+
+	parentTbinfo = tbinfo->parents[0];
+	if (parentTbinfo->unsafe_partitions)
+		return true;
+	while (parentTbinfo->ispartition)
+	{
+		Assert(parentTbinfo->numParents == 1);
+		parentTbinfo = parentTbinfo->parents[0];
+		if (parentTbinfo->unsafe_partitions)
+			return true;
+	}
+
+	return false;
+}
+
+/*
  * dumpTableData -
  *	  dump the contents of a single table
  *
@@ -2408,34 +2440,40 @@ dumpTableData(Archive *fout, const TableDataInfo *tdinfo)
 	PQExpBuffer copyBuf = createPQExpBuffer();
 	PQExpBuffer clistBuf = createPQExpBuffer();
 	DataDumperPtr dumpFn;
+	char	   *tdDefn = NULL;
 	char	   *copyStmt;
 	const char *copyFrom;
 
 	/* We had better have loaded per-column details about this table */
 	Assert(tbinfo->interesting);
 
+	/*
+	 * When load-via-partition-root is set or forced, get the root table name
+	 * for the partition table, so that we can reload data through the root
+	 * table.  Then construct a comment to be inserted into the TOC entry's
+	 * defn field, so that such cases can be identified reliably.
+	 */
+	if (tbinfo->ispartition &&
+		(dopt->load_via_partition_root ||
+		 forcePartitionRootLoad(tbinfo)))
+	{
+		TableInfo  *parentTbinfo;
+
+		parentTbinfo = getRootTableInfo(tbinfo);
+		copyFrom = fmtQualifiedDumpable(parentTbinfo);
+		printfPQExpBuffer(copyBuf, "-- load via partition root %s",
+						  copyFrom);
+		tdDefn = pg_strdup(copyBuf->data);
+	}
+	else
+		copyFrom = fmtQualifiedDumpable(tbinfo);
+
 	if (dopt->dump_inserts == 0)
 	{
 		/* Dump/restore using COPY */
 		dumpFn = dumpTableData_copy;
-
-		/*
-		 * When load-via-partition-root is set, get the root table name for
-		 * the partition table, so that we can reload data through the root
-		 * table.
-		 */
-		if (dopt->load_via_partition_root && tbinfo->ispartition)
-		{
-			TableInfo  *parentTbinfo;
-
-			parentTbinfo = getRootTableInfo(tbinfo);
-			copyFrom = fmtQualifiedDumpable(parentTbinfo);
-		}
-		else
-			copyFrom = fmtQualifiedDumpable(tbinfo);
-
 		/* must use 2 steps here 'cause fmtId is nonreentrant */
-		appendPQExpBuffer(copyBuf, "COPY %s ",
+		printfPQExpBuffer(copyBuf, "COPY %s ",
 						  copyFrom);
 		appendPQExpBuffer(copyBuf, "%s FROM stdin;\n",
 						  fmtCopyColumnList(tbinfo, clistBuf));
@@ -2463,6 +2501,7 @@ dumpTableData(Archive *fout, const TableDataInfo *tdinfo)
 									   .owner = tbinfo->rolname,
 									   .description = "TABLE DATA",
 									   .section = SECTION_DATA,
+									   .createStmt = tdDefn,
 									   .copyStmt = copyStmt,
 									   .deps = &(tbinfo->dobj.dumpId),
 									   .nDeps = 1,
@@ -6655,6 +6694,76 @@ getInherits(Archive *fout, int *numInherits)
 }
 
 /*
+ * getPartitioningInfo
+ *	  get information about partitioning
+ *
+ * For the most part, we only collect partitioning info about tables we
+ * intend to dump.  However, this function has to consider all partitioned
+ * tables in the database, because we need to know about parents of partitions
+ * we are going to dump even if the parents themselves won't be dumped.
+ *
+ * Specifically, what we need to know is whether each partitioned table
+ * has an "unsafe" partitioning scheme that requires us to force
+ * load-via-partition-root mode for its children.  Currently the only case
+ * for which we force that is hash partitioning on enum columns, since the
+ * hash codes depend on enum value OIDs which won't be replicated across
+ * dump-and-reload.  There are other cases in which load-via-partition-root
+ * might be necessary, but we expect users to cope with them.
+ */
+void
+getPartitioningInfo(Archive *fout)
+{
+	PQExpBuffer query;
+	PGresult   *res;
+	int			ntups;
+
+	/* hash partitioning didn't exist before v11 */
+	if (fout->remoteVersion < 110000)
+		return;
+	/* needn't bother if schema-only dump */
+	if (fout->dopt->schemaOnly)
+		return;
+
+	query = createPQExpBuffer();
+
+	/*
+	 * Unsafe partitioning schemes are exactly those for which hash enum_ops
+	 * appears among the partition opclasses.  We needn't check partstrat.
+	 *
+	 * Note that this query may well retrieve info about tables we aren't
+	 * going to dump and hence have no lock on.  That's okay since we need not
+	 * invoke any unsafe server-side functions.
+	 */
+	appendPQExpBufferStr(query,
+						 "SELECT partrelid FROM pg_partitioned_table WHERE\n"
+						 "(SELECT c.oid FROM pg_opclass c JOIN pg_am a "
+						 "ON c.opcmethod = a.oid\n"
+						 "WHERE opcname = 'enum_ops' "
+						 "AND opcnamespace = 'pg_catalog'::regnamespace "
+						 "AND amname = 'hash') = ANY(partclass)");
+
+	res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
+
+	ntups = PQntuples(res);
+
+	for (int i = 0; i < ntups; i++)
+	{
+		Oid			tabrelid = atooid(PQgetvalue(res, i, 0));
+		TableInfo  *tbinfo;
+
+		tbinfo = findTableByOid(tabrelid);
+		if (tbinfo == NULL)
+			pg_fatal("failed sanity check, table OID %u appearing in pg_partitioned_table not found",
+					 tabrelid);
+		tbinfo->unsafe_partitions = true;
+	}
+
+	PQclear(res);
+
+	destroyPQExpBuffer(query);
+}
+
+/*
  * getIndexes
  *	  get information about every index on a dumpable table
  *