Separate build of citus.so and citus_columnar.so.

Because columnar code is statically-linked to both modules, it doesn't
make sense to load them both at once.

A subsequent commit will make the modules entirely separate and allow
loading them both simultaneously.

Makefile

@@ -13,10 +13,16 @@ include Makefile.global
 
 all: extension
 
+
+#build columnar only
+columnar:
+	$(MAKE) -C src/backend/columnar all
 # build extension
-extension: $(citus_top_builddir)/src/include/citus_version.h
+extension: $(citus_top_builddir)/src/include/citus_version.h columnar
 	$(MAKE) -C src/backend/distributed/ all
-install-extension: extension
+install-columnar: columnar
+	$(MAKE) -C src/backend/columnar install
+install-extension: extension install-columnar
 	$(MAKE) -C src/backend/distributed/ install
 install-headers: extension
 	$(MKDIR_P) '$(DESTDIR)$(includedir_server)/distributed/'
@@ -27,6 +33,7 @@ install-headers: extension
 
 clean-extension:
 	$(MAKE) -C src/backend/distributed/ clean
+	$(MAKE) -C src/backend/columnar/ clean
 clean-full:
 	$(MAKE) -C src/backend/distributed/ clean-full
 .PHONY: extension install-extension clean-extension clean-full
@@ -35,6 +42,7 @@ install: install-extension install-headers
 install-downgrades:
 	$(MAKE) -C src/backend/distributed/ install-downgrades
 install-all: install-headers
+	$(MAKE) -C src/backend/columnar/ install-all
 	$(MAKE) -C src/backend/distributed/ install-all
 
 clean: clean-extension

src/backend/columnar/Makefile

@@ -0,0 +1,17 @@
+citus_subdir = src/backend/columnar
+citus_top_builddir = ../../..
+safestringlib_srcdir = $(citus_abs_top_srcdir)/vendor/safestringlib
+SUBDIRS = . safeclib
+SUBDIRS +=
+ENSURE_SUBDIRS_EXIST := $(shell mkdir -p $(SUBDIRS))
+OBJS += \
+	$(patsubst $(citus_abs_srcdir)/%.c,%.o,$(foreach dir,$(SUBDIRS), $(sort $(wildcard $(citus_abs_srcdir)/$(dir)/*.c))))
+
+MODULE_big = citus_columnar
+
+PG_CPPFLAGS += -I$(libpq_srcdir) -I$(safestringlib_srcdir)/include
+
+include $(citus_top_builddir)/Makefile.global
+
+.PHONY: install-all
+install-all: install

src/backend/columnar/columnar.c

@@ -22,6 +22,7 @@
 
 #include "citus_version.h"
 #include "columnar/columnar.h"
+#include "columnar/columnar_tableam.h"
 
 /* Default values for option parameters */
 #define DEFAULT_STRIPE_ROW_COUNT 150000
@@ -53,6 +54,14 @@ static const struct config_enum_entry columnar_compression_options[] =
 	{ NULL, 0, false }
 };
 
+void
+columnar_init(void)
+{
+	columnar_init_gucs();
+	columnar_tableam_init();
+}
+
+
 void
 columnar_init_gucs()
 {

src/backend/columnar/columnar_debug.c

@@ -11,7 +11,6 @@
 #include "postgres.h"
 
 #include "funcapi.h"
-#include "pg_config.h"
 #include "access/nbtree.h"
 #include "access/table.h"
 #include "catalog/pg_am.h"

src/backend/columnar/mod.c

@@ -18,13 +18,15 @@
 #include "citus_version.h"
 
 #include "columnar/columnar.h"
-#include "columnar/mod.h"
-
 #include "columnar/columnar_tableam.h"
 
+
+PG_MODULE_MAGIC;
+
+void _PG_init(void);
+
 void
-columnar_init(void)
+_PG_init(void)
 {
-	columnar_init_gucs();
-	columnar_tableam_init();
+	columnar_init();
 }

src/backend/distributed/Makefile

@@ -30,9 +30,11 @@ ENSURE_SUBDIRS_EXIST := $(shell mkdir -p $(SUBDIRS))
 
 # That patsubst rule searches all directories listed in SUBDIRS for .c
 # files, and adds the corresponding .o files to OBJS
-OBJS += \
+ALL_OBJS = \
 	$(patsubst $(citus_abs_srcdir)/%.c,%.o,$(foreach dir,$(SUBDIRS), $(sort $(wildcard $(citus_abs_srcdir)/$(dir)/*.c))))
 
+OBJS += $(filter-out ../columnar/mod.o,$(ALL_OBJS))
+
 # be explicit about the default target
 all:
 
@@ -84,7 +86,8 @@ endif
 .PHONY: clean-full install install-downgrades install-all
 
 cleanup-before-install:
-	rm -f $(DESTDIR)$(datadir)/$(datamoduledir)/citus*
+	rm -f $(DESTDIR)$(datadir)/$(datamoduledir)/citus.control
+	rm -f $(DESTDIR)$(datadir)/$(datamoduledir)/citus--*
 
 install: cleanup-before-install
 

src/backend/distributed/shared_library_init.c

@@ -95,7 +95,7 @@
 #include "utils/syscache.h"
 #include "utils/varlena.h"
 
-#include "columnar/mod.h"
+#include "columnar/columnar.h"
 
 /* marks shared object as one loadable by the postgres version compiled against */
 PG_MODULE_MAGIC;

src/include/columnar/columnar.h

@@ -207,6 +207,7 @@ extern int columnar_compression_level;
 typedef void (*ColumnarTableSetOptions_hook_type)(Oid relid, ColumnarOptions options);
 extern ColumnarTableSetOptions_hook_type ColumnarTableSetOptions_hook;
 
+extern void columnar_init(void);
 extern void columnar_init_gucs(void);
 
 extern CompressionType ParseCompressionType(const char *compressionTypeString);

src/include/columnar/mod.h

@@ -1,19 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * mod.h
- *
- * Type and function declarations for columnar
- *
- * Copyright (c) Citus Data, Inc.
- *
- *-------------------------------------------------------------------------
- */
-
-#ifndef MOD_H
-#define MOD_H
-
-/* Function declarations for extension loading and unloading */
-extern void columnar_init(void);
-extern void columnar_fini(void);
-
-#endif /* MOD_H */

src/test/regress/expected/columnar_create.out

@@ -185,3 +185,11 @@ SELECT columnar_test_helpers.columnar_metadata_has_storage_id(:columnar_temp_sto
  f
 (1 row)
 
+--
+-- Will throw error due to redefining GUCs, because citus is already
+-- loaded and has already initialized columnar code. This test is to
+-- ensure that the citus_columnar module is built and present, and
+-- that it can be loaded without link failures.
+--
+LOAD 'citus_columnar';
+ERROR:  attempt to redefine parameter "columnar.compression"

src/test/regress/sql/columnar_create.sql

@@ -129,3 +129,11 @@ SELECT COUNT(*)=1 FROM pg_class WHERE relname='columnar_temp';
 SELECT COUNT(*)=0 FROM columnar_temp;
 -- since we deleted all the rows, we shouldn't have any stripes for table
 SELECT columnar_test_helpers.columnar_metadata_has_storage_id(:columnar_temp_storage_id);
+
+--
+-- Will throw error due to redefining GUCs, because citus is already
+-- loaded and has already initialized columnar code. This test is to
+-- ensure that the citus_columnar module is built and present, and
+-- that it can be loaded without link failures.
+--
+LOAD 'citus_columnar';