Fixing NULL compression dump/restore issue

.unreleased/pr_8153

@@ -0,0 +1 @@
+Fixes: #8153 Restoring a database having NULL compressed data

test/sql/utils/pg_dump_aux_plain_dump.sh

@@ -0,0 +1,15 @@
+DUMPFILE=${DUMPFILE:-$1}
+EXTRA_PGOPTIONS=${EXTRA_PGOPTIONS:-$2}
+DUMP_OPTIONS=${DUMP_OPTIONS:-$3}
+# Override PGOPTIONS to remove verbose output
+PGOPTIONS="--client-min-messages=warning $EXTRA_PGOPTIONS"
+
+export PGOPTIONS
+echo ${DUMP_OPTIONS}
+echo $DUMP_OPTIONS
+echo $(echo $DUMP_OPTIONS)
+
+${PG_BINDIR}/pg_dump -h ${PGHOST} -U ${TEST_ROLE_SUPERUSER} ${DUMP_OPTIONS} -Fp ${TEST_DBNAME} -f ${DUMPFILE}
+# ${PG_BINDIR}/pg_dump -h ${PGHOST} -U ${TEST_ROLE_SUPERUSER} ${DUMP_OPTIONS} -Fp ${TEST_DBNAME} > /dev/null 2>&1 -f ${DUMPFILE}
+${PG_BINDIR}/dropdb -h ${PGHOST} -U ${TEST_ROLE_SUPERUSER} ${TEST_DBNAME}
+${PG_BINDIR}/createdb -h ${PGHOST} -U ${TEST_ROLE_SUPERUSER} ${TEST_DBNAME}

tsl/src/compression/algorithms/null.c

@@ -35,8 +35,15 @@ null_compressed_send(CompressedDataHeader *header, StringInfo buffer)
 extern Datum
 null_compressed_recv(StringInfo buffer)
 {
-	elog(ERROR, "null compression doesn't implement recv");
-	PG_RETURN_VOID();
+	/* Sanity checks for invalid buffer */
+	if (buffer->len == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("compressed data is invalid to be a null compressed block")));
+	if (buffer->data == NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("compressed data is NULL")));
+	PG_RETURN_POINTER(null_compressor_get_dummy_block());
 }
 
 extern Compressor *

tsl/src/compression/compression.c

@@ -2015,14 +2015,7 @@ tsl_compressed_data_recv(PG_FUNCTION_ARGS)
 	if (header.compression_algorithm >= _END_COMPRESSION_ALGORITHMS)
 		elog(ERROR, "invalid compression algorithm %d", header.compression_algorithm);
 
-	if (header.compression_algorithm == COMPRESSION_ALGORITHM_NULL)
-	{
-		PG_RETURN_NULL();
-	}
-	else
-	{
-		return definitions[header.compression_algorithm].compressed_data_recv(buf);
-	}
+	return definitions[header.compression_algorithm].compressed_data_recv(buf);
 }
 
 extern Datum

tsl/test/expected/compression_null_dump_restore.out

@@ -0,0 +1,80 @@
+-- This file and its contents are licensed under the Timescale License.
+-- Please see the included NOTICE for copyright information and
+-- LICENSE-TIMESCALE for a copy of the license.
+-- This test is to verify fixing the behaviour reported in: SDC #2912
+-- Create destination database
+\set TEST_DBNAME_3 :TEST_DBNAME _3
+\c postgres :ROLE_SUPERUSER
+CREATE DATABASE :TEST_DBNAME_3;
+\c :TEST_DBNAME_3 :ROLE_SUPERUSER
+create extension timescaledb CASCADE;
+-- Create source database
+\set TEST_DBNAME_2 :TEST_DBNAME _2
+\c postgres :ROLE_SUPERUSER
+CREATE DATABASE :TEST_DBNAME_2;
+\c :TEST_DBNAME_2 :ROLE_SUPERUSER
+create extension timescaledb CASCADE;
+-- Create compressed table with one column having all NULL
+-- values, so it will be compressed with the NULL algorithm
+--
+create table null_dump (ts int primary key, n int);
+select create_hypertable('null_dump', 'ts');
+   create_hypertable    
+------------------------
+ (1,public,null_dump,t)
+(1 row)
+
+insert into null_dump values (1), (2), (3), (4);
+alter table null_dump set (timescaledb.compress, timescaledb.compress_orderby = 'ts');
+select compress_chunk(show_chunks('null_dump'));
+             compress_chunk             
+----------------------------------------
+ _timescaledb_internal._hyper_1_1_chunk
+(1 row)
+
+-- Dump the content of the source database
+\setenv TEST_DBNAME :TEST_DBNAME_2
+\setenv DUMP_OPTIONS '--quote-all-identifiers --no-tablespaces --no-owner --no-privileges --exclude-schema=test'
+\c postgres :ROLE_SUPERUSER
+\! utils/pg_dump_aux_plain_dump.sh dump/null-compress-dump.sql
+--quote-all-identifiers --no-tablespaces --no-owner --no-privileges --exclude-schema=test
+--quote-all-identifiers --no-tablespaces --no-owner --no-privileges --exclude-schema=test
+--quote-all-identifiers --no-tablespaces --no-owner --no-privileges --exclude-schema=test
+pg_dump: warning: there are circular foreign-key constraints on this table:
+pg_dump: detail: hypertable
+pg_dump: hint: You might not be able to restore the dump without using --disable-triggers or temporarily dropping the constraints.
+pg_dump: hint: Consider using a full dump instead of a --data-only dump to avoid this problem.
+pg_dump: warning: there are circular foreign-key constraints on this table:
+pg_dump: detail: chunk
+pg_dump: hint: You might not be able to restore the dump without using --disable-triggers or temporarily dropping the constraints.
+pg_dump: hint: Consider using a full dump instead of a --data-only dump to avoid this problem.
+pg_dump: warning: there are circular foreign-key constraints on this table:
+pg_dump: detail: continuous_agg
+pg_dump: hint: You might not be able to restore the dump without using --disable-triggers or temporarily dropping the constraints.
+pg_dump: hint: Consider using a full dump instead of a --data-only dump to avoid this problem.
+-- Restore the data into the destination database
+\c :TEST_DBNAME_3 :ROLE_SUPERUSER
+select public.timescaledb_pre_restore();
+ timescaledb_pre_restore 
+-------------------------
+ t
+(1 row)
+
+\set ECHO none
+select public.timescaledb_post_restore();
+ timescaledb_post_restore 
+--------------------------
+ t
+(1 row)
+
+select * from public.null_dump order by 1;
+ ts | n 
+----+---
+  1 |  
+  2 |  
+  3 |  
+  4 |  
+(4 rows)
+
+drop database db_compression_null_dump_restore_2;
+drop database db_compression_null_dump_restore_3;

tsl/test/sql/CMakeLists.txt

@@ -33,6 +33,7 @@ set(TEST_FILES
     compression_fks.sql
     compression_indexcreate.sql
     compression_insert.sql
+    compression_null_dump_restore.sql
     compression_nulls_and_defaults.sql
     compression_policy.sql
     compression_qualpushdown.sql

tsl/test/sql/compression_null_dump_restore.sql

@@ -0,0 +1,51 @@
+-- This file and its contents are licensed under the Timescale License.
+-- Please see the included NOTICE for copyright information and
+-- LICENSE-TIMESCALE for a copy of the license.
+
+-- This test is to verify fixing the behaviour reported in: SDC #2912
+
+-- Create destination database
+\set TEST_DBNAME_3 :TEST_DBNAME _3
+\c postgres :ROLE_SUPERUSER
+CREATE DATABASE :TEST_DBNAME_3;
+\c :TEST_DBNAME_3 :ROLE_SUPERUSER
+create extension timescaledb CASCADE;
+
+-- Create source database
+\set TEST_DBNAME_2 :TEST_DBNAME _2
+\c postgres :ROLE_SUPERUSER
+CREATE DATABASE :TEST_DBNAME_2;
+\c :TEST_DBNAME_2 :ROLE_SUPERUSER
+create extension timescaledb CASCADE;
+
+-- Create compressed table with one column having all NULL
+-- values, so it will be compressed with the NULL algorithm
+--
+create table null_dump (ts int primary key, n int);
+select create_hypertable('null_dump', 'ts');
+insert into null_dump values (1), (2), (3), (4);
+alter table null_dump set (timescaledb.compress, timescaledb.compress_orderby = 'ts');
+select compress_chunk(show_chunks('null_dump'));
+
+-- Dump the content of the source database
+\setenv TEST_DBNAME :TEST_DBNAME_2
+\setenv DUMP_OPTIONS '--quote-all-identifiers --no-tablespaces --no-owner --no-privileges --exclude-schema=test'
+\c postgres :ROLE_SUPERUSER
+\! utils/pg_dump_aux_plain_dump.sh dump/null-compress-dump.sql
+
+-- Restore the data into the destination database
+\c :TEST_DBNAME_3 :ROLE_SUPERUSER
+select public.timescaledb_pre_restore();
+\set ECHO none
+\o /dev/null
+SET client_min_messages = 'error';
+\i dump/null-compress-dump.sql
+\o
+\set ECHO queries
+select public.timescaledb_post_restore();
+
+select * from public.null_dump order by 1;
+
+\c postgres :ROLE_SUPERUSER
+drop database :TEST_DBNAME_2;
+drop database :TEST_DBNAME_3;

tsl/test/src/compression_unit_test.c

@@ -999,14 +999,8 @@ test_null()
 		TestAssertTrue(transmission.len > 0);
 		TestAssertTrue(transmission.data != NULL);
 
-		LOCAL_FCINFO(local_fcinfo, 1);
-		local_fcinfo->args[0] =
-			(NullableDatum){ .value = PointerGetDatum(&transmission), .isnull = false };
-
-		// Call the function directly
-		tsl_compressed_data_recv(local_fcinfo);
-
-		TestAssertTrue(local_fcinfo->isnull);
+		Datum res = DirectFunctionCall1(tsl_compressed_data_recv, PointerGetDatum(&transmission));
+		TestAssertTrue(DatumGetPointer(res) != NULL);
 	}
 	{
 		void *compressed = null_compressor_get_dummy_block();