2 files changed, 79 insertions, 11 deletions

diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 717bb0b2aa9..47f62c28d42 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -30,6 +30,7 @@
 #include "catalog/objectaccess.h"
 #include "catalog/pg_sequence.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_xlog.h"
 #include "commands/defrem.h"
 #include "commands/sequence.h"
 #include "commands/tablecmds.h"
@@ -95,6 +96,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
 static SeqTableData *last_used_seq = NULL;
 
 static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_fork_with_data(Relation rel, HeapTuple tuple, ForkNumber forkNum);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -133,12 +135,6 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 	bool		pgs_nulls[Natts_pg_sequence];
 	int			i;
 
-	/* Unlogged sequences are not implemented -- not clear if useful. */
-	if (seq->sequence->relpersistence == RELPERSISTENCE_UNLOGGED)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("unlogged sequences are not supported")));
-
 	/*
 	 * If if_not_exists was given and a relation with the same name already
 	 * exists, bail out. (Note: we needn't check this when not if_not_exists,
@@ -492,10 +488,34 @@ SetSequence(Oid seq_relid, bool transactional, int64 last_value, int64 log_cnt,
 
 /*
  * Initialize a sequence's relation with the specified tuple as content
+ *
+ * This handles unlogged sequences by writing to both the main and the init
+ * fork as necessary.
  */
 static void
 fill_seq_with_data(Relation rel, HeapTuple tuple)
 {
+	fill_seq_fork_with_data(rel, tuple, MAIN_FORKNUM);
+
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED)
+	{
+		SMgrRelation srel;
+
+		srel = smgropen(rel->rd_node, InvalidBackendId);
+		smgrcreate(srel, INIT_FORKNUM, false);
+		log_smgrcreate(&rel->rd_node, INIT_FORKNUM);
+		fill_seq_fork_with_data(rel, tuple, INIT_FORKNUM);
+		FlushRelationBuffers(rel);
+		smgrclose(srel);
+	}
+}
+
+/*
+ * Initialize a sequence's relation fork with the specified tuple as content
+ */
+static void
+fill_seq_fork_with_data(Relation rel, HeapTuple tuple, ForkNumber forkNum)
+{
 	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
@@ -503,7 +523,7 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
+	buf = ReadBufferExtended(rel, forkNum, P_NEW, RBM_NORMAL, NULL);
 	Assert(BufferGetBlockNumber(buf) == 0);
 
 	page = BufferGetPage(buf);
@@ -549,7 +569,7 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 		elog(ERROR, "failed to add sequence tuple to page");
 
 	/* XLOG stuff */
-	if (RelationNeedsWAL(rel))
+	if (RelationNeedsWAL(rel) || forkNum == INIT_FORKNUM)
 	{
 		xl_seq_rec	xlrec;
 		XLogRecPtr	recptr;
@@ -683,6 +703,28 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 }
 
 void
+SequenceChangePersistence(Oid relid, char newrelpersistence)
+{
+	SeqTable	elm;
+	Relation	seqrel;
+	Buffer		buf;
+	HeapTupleData seqdatatuple;
+
+	init_sequence(relid, &elm, &seqrel);
+
+	/* check the comment above nextval_internal()'s equivalent call. */
+	if (RelationNeedsWAL(seqrel))
+		GetTopTransactionId();
+
+	(void) read_seq_tuple(seqrel, &buf, &seqdatatuple);
+	RelationSetNewRelfilenode(seqrel, newrelpersistence);
+	fill_seq_with_data(seqrel, &seqdatatuple);
+	UnlockReleaseBuffer(buf);
+
+	relation_close(seqrel, NoLock);
+}
+
+void
 DeleteSequenceTuple(Oid relid)
 {
 	Relation	rel;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index a241b444975..4dd545cdd20 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -319,6 +319,7 @@ struct DropRelationCallbackState
 #define		ATT_COMPOSITE_TYPE		0x0010
 #define		ATT_FOREIGN_TABLE		0x0020
 #define		ATT_PARTITIONED_INDEX	0x0040
+#define		ATT_SEQUENCE			0x0080
 
 /*
  * ForeignTruncateInfo
@@ -4660,7 +4661,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_MISC;
 			break;
 		case AT_SetLogged:		/* SET LOGGED */
-			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE);
+			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_SEQUENCE);
 			if (tab->chgPersistence)
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
@@ -4675,7 +4676,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_MISC;
 			break;
 		case AT_SetUnLogged:	/* SET UNLOGGED */
-			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE);
+			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_SEQUENCE);
 			if (tab->chgPersistence)
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
@@ -5425,7 +5426,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
 		 * and assigns a new relfilenode, we automatically create or drop an
 		 * init fork for the relation as appropriate.
 		 */
-		if (tab->rewrite > 0)
+		if (tab->rewrite > 0 && tab->relkind != RELKIND_SEQUENCE)
 		{
 			/* Build a temporary relation and copy data */
 			Relation	OldHeap;
@@ -5546,6 +5547,11 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
 
 			InvokeObjectPostAlterHook(RelationRelationId, tab->relid, 0);
 		}
+		else if (tab->rewrite > 0 && tab->relkind == RELKIND_SEQUENCE)
+		{
+			if (tab->chgPersistence)
+				SequenceChangePersistence(tab->relid, tab->newrelpersistence);
+		}
 		else
 		{
 			/*
@@ -5564,6 +5570,23 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
 			if (tab->newTableSpace)
 				ATExecSetTableSpace(tab->relid, tab->newTableSpace, lockmode);
 		}
+
+		/*
+		 * Also change persistence of owned sequences, so that it matches the
+		 * table persistence.
+		 */
+		if (tab->chgPersistence)
+		{
+			List	   *seqlist = getOwnedSequences(tab->relid);
+			ListCell   *lc;
+
+			foreach(lc, seqlist)
+			{
+				Oid         seq_relid = lfirst_oid(lc);
+
+				SequenceChangePersistence(seq_relid, tab->newrelpersistence);
+			}
+		}
 	}
 
 	/*
@@ -6224,6 +6247,9 @@ ATSimplePermissions(AlterTableType cmdtype, Relation rel, int allowed_targets)
 		case RELKIND_FOREIGN_TABLE:
 			actual_target = ATT_FOREIGN_TABLE;
 			break;
+		case RELKIND_SEQUENCE:
+			actual_target = ATT_SEQUENCE;
+			break;
 		default:
 			actual_target = 0;
 			break;