Implement nontransactional truncate

cstore.h

@@ -283,7 +283,7 @@ extern StringInfo DecompressBuffer(StringInfo buffer, CompressionType compressio
 extern void DeleteDataFileMetadataRowIfExists(Oid relfilenode);
 extern void InitCStoreDataFileMetadata(Oid relfilenode, int blockRowCount);
 extern void InsertStripeMetadataRow(Oid relfilenode, StripeMetadata *stripe);
-extern DataFileMetadata * ReadDataFileMetadata(Oid relfilenode);
+extern DataFileMetadata * ReadDataFileMetadata(Oid relfilenode, bool missingOk);
 extern void SaveStripeSkipList(Oid relfilenode, uint64 stripe,
 							   StripeSkipList *stripeSkipList,
 							   TupleDesc tupleDescriptor);

cstore_metadata_tables.c

@@ -343,7 +343,7 @@ InsertStripeMetadataRow(Oid relfilenode, StripeMetadata *stripe)
  * from cstore_data_files and cstore_stripes.
  */
 DataFileMetadata *
-ReadDataFileMetadata(Oid relfilenode)
+ReadDataFileMetadata(Oid relfilenode, bool missingOk)
 {
 	Oid cstoreStripesOid = InvalidOid;
 	Relation cstoreStripes = NULL;
@@ -357,10 +357,17 @@ ReadDataFileMetadata(Oid relfilenode)
 	DataFileMetadata *datafileMetadata = palloc0(sizeof(DataFileMetadata));
 	found = ReadCStoreDataFiles(relfilenode, &datafileMetadata->blockRowCount);
 	if (!found)
+	{
+		if (!missingOk)
 		{
 			ereport(ERROR, (errmsg("Relfilenode %d doesn't belong to a cstore table.",
 								   relfilenode)));
 		}
+		else
+		{
+			return NULL;
+		}
+	}
 
 	ScanKeyInit(&scanKey[0], Anum_cstore_stripes_relfilenode,
 				BTEqualStrategyNumber, F_OIDEQ, Int32GetDatum(relfilenode));

cstore_reader.c

@@ -88,7 +88,7 @@ CStoreBeginRead(Relation relation, TupleDesc tupleDescriptor,
 	MemoryContext stripeReadContext = NULL;
 	Oid relNode = relation->rd_node.relNode;
 
-	datafileMetadata = ReadDataFileMetadata(relNode);
+	datafileMetadata = ReadDataFileMetadata(relNode, false);
 
 	/*
 	 * We allocate all stripe specific data in the stripeReadContext, and reset
@@ -309,7 +309,7 @@ CStoreTableRowCount(Relation relation)
 	ListCell *stripeMetadataCell = NULL;
 	uint64 totalRowCount = 0;
 
-	datafileMetadata = ReadDataFileMetadata(relation->rd_node.relNode);
+	datafileMetadata = ReadDataFileMetadata(relation->rd_node.relNode, false);
 
 	foreach(stripeMetadataCell, datafileMetadata->stripeMetadataList)
 	{

cstore_tableam.c

@@ -443,7 +443,20 @@ cstore_relation_set_new_filenode(Relation rel,
 								 MultiXactId *minmulti)
 {
 	SMgrRelation srel;
+	DataFileMetadata *metadata = ReadDataFileMetadata(rel->rd_node.relNode, true);
+	uint64 blockRowCount = 0;
+
+	if (metadata != NULL)
+	{
+		/* existing table (e.g. TRUNCATE), use existing blockRowCount */
+		blockRowCount = metadata->blockRowCount;
+	}
+	else
+	{
+		/* new table, use options */
 		CStoreOptions *options = CStoreTableAMGetOptions();
+		blockRowCount = options->blockRowCount;
+	}
 
 	/* delete old relfilenode metadata */
 	DeleteDataFileMetadataRowIfExists(rel->rd_node.relNode);
@@ -452,7 +465,7 @@ cstore_relation_set_new_filenode(Relation rel,
 	*freezeXid = RecentXmin;
 	*minmulti = GetOldestMultiXactId();
 	srel = RelationCreateStorage(*newrnode, persistence);
-	InitCStoreDataFileMetadata(newrnode->relNode, options->blockRowCount);
+	InitCStoreDataFileMetadata(newrnode->relNode, blockRowCount);
 	smgrclose(srel);
 }
 
@@ -460,7 +473,20 @@ cstore_relation_set_new_filenode(Relation rel,
 static void
 cstore_relation_nontransactional_truncate(Relation rel)
 {
-	elog(ERROR, "cstore_relation_nontransactional_truncate not implemented");
+	DataFileMetadata *metadata = ReadDataFileMetadata(rel->rd_node.relNode, false);
+
+	/*
+	 * No need to set new relfilenode, since the table was created in this
+	 * transaction and no other transaction can see this relation yet. We
+	 * can just truncate the relation.
+	 *
+	 * This is similar to what is done in heapam_relation_nontransactional_truncate.
+	 */
+	RelationTruncate(rel, 0);
+
+	/* Delete old relfilenode metadata and recreate it */
+	DeleteDataFileMetadataRowIfExists(rel->rd_node.relNode);
+	InitCStoreDataFileMetadata(rel->rd_node.relNode, metadata->blockRowCount);
 }
 
 

cstore_writer.c

@@ -75,7 +75,7 @@ CStoreBeginWrite(Relation relation,
 	uint64 currentStripeId = 0;
 	Oid relNode = relation->rd_node.relNode;
 
-	datafileMetadata = ReadDataFileMetadata(relNode);
+	datafileMetadata = ReadDataFileMetadata(relNode, false);
 
 	/*
 	 * If stripeMetadataList is not empty, jump to the position right after

expected/am_truncate.out

@@ -153,6 +153,30 @@ SELECT :cstore_data_files_before_truncate - count(*) FROM cstore.cstore_data_fil
         0
 (1 row)
 
+-- test if truncation in the same transaction that created the table works properly
+BEGIN;
+CREATE TABLE cstore_same_transaction_truncate(a int) USING cstore_tableam;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(1, 100);
+TRUNCATE cstore_same_transaction_truncate;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(20, 23);
+COMMIT;
+-- should output "1" for the newly created relation
+SELECT count(*) - :cstore_data_files_before_truncate FROM cstore.cstore_data_files;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT * FROM cstore_same_transaction_truncate;
+ a  
+----
+ 20
+ 21
+ 22
+ 23
+(4 rows)
+
+DROP TABLE cstore_same_transaction_truncate;
 -- test if a cached truncate from a pl/pgsql function works
 CREATE FUNCTION cstore_truncate_test_regular_func() RETURNS void AS $$
 BEGIN

expected/fdw_truncate.out

@@ -150,6 +150,30 @@ SELECT :cstore_data_files_before_truncate - count(*) FROM cstore.cstore_data_fil
         0
 (1 row)
 
+-- test if truncation in the same transaction that created the table works properly
+BEGIN;
+CREATE FOREIGN TABLE cstore_same_transaction_truncate(a int) SERVER cstore_server;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(1, 100);
+TRUNCATE cstore_same_transaction_truncate;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(20, 23);
+COMMIT;
+-- should output "1" for the newly created relation
+SELECT count(*) - :cstore_data_files_before_truncate FROM cstore.cstore_data_files;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT * FROM cstore_same_transaction_truncate;
+ a  
+----
+ 20
+ 21
+ 22
+ 23
+(4 rows)
+
+DROP FOREIGN TABLE cstore_same_transaction_truncate;
 -- test if a cached truncate from a pl/pgsql function works
 CREATE FUNCTION cstore_truncate_test_regular_func() RETURNS void AS $$
 BEGIN

sql/am_truncate.sql

@@ -65,6 +65,20 @@ SELECT * from cstore_truncate_test;
 -- make sure TRUNATE deletes metadata for old relfilenode
 SELECT :cstore_data_files_before_truncate - count(*) FROM cstore.cstore_data_files;
 
+-- test if truncation in the same transaction that created the table works properly
+BEGIN;
+CREATE TABLE cstore_same_transaction_truncate(a int) USING cstore_tableam;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(1, 100);
+TRUNCATE cstore_same_transaction_truncate;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(20, 23);
+COMMIT;
+
+-- should output "1" for the newly created relation
+SELECT count(*) - :cstore_data_files_before_truncate FROM cstore.cstore_data_files;
+SELECT * FROM cstore_same_transaction_truncate;
+
+DROP TABLE cstore_same_transaction_truncate;
+
 -- test if a cached truncate from a pl/pgsql function works
 CREATE FUNCTION cstore_truncate_test_regular_func() RETURNS void AS $$
 BEGIN

sql/fdw_truncate.sql

@@ -62,6 +62,20 @@ SELECT * from cstore_truncate_test;
 -- make sure TRUNATE deletes metadata for old relfilenode
 SELECT :cstore_data_files_before_truncate - count(*) FROM cstore.cstore_data_files;
 
+-- test if truncation in the same transaction that created the table works properly
+BEGIN;
+CREATE FOREIGN TABLE cstore_same_transaction_truncate(a int) SERVER cstore_server;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(1, 100);
+TRUNCATE cstore_same_transaction_truncate;
+INSERT INTO cstore_same_transaction_truncate SELECT * FROM generate_series(20, 23);
+COMMIT;
+
+-- should output "1" for the newly created relation
+SELECT count(*) - :cstore_data_files_before_truncate FROM cstore.cstore_data_files;
+SELECT * FROM cstore_same_transaction_truncate;
+
+DROP FOREIGN TABLE cstore_same_transaction_truncate;
+
 -- test if a cached truncate from a pl/pgsql function works
 CREATE FUNCTION cstore_truncate_test_regular_func() RETURNS void AS $$
 BEGIN