[lsm] add InitLsmLogBlocks

Author: xxiao23

src/backend/storage/lsm/Makefile

@@ -0,0 +1,18 @@
+#-------------------------------------------------------------------------
+#
+# Makefile--
+# Makefile for storage/lsm
+#
+# IDENTIFICATION
+# src/backend/storage/lsm/Makefile
+#
+#-------------------------------------------------------------------------
+
+subdir = src/backend/storage/lsm
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+
+OBJS = \
+lsm.o
+
+include $(top_srcdir)/src/backend/common.mk

src/backend/storage/lsm/lsm.c

@@ -0,0 +1,28 @@
+/*-------------------------------------------------------------------------
+ *
+ * lsm.c
+ * Log structure merge (LSM) tree methods 
+ *
+ * IDENTIFICATION
+ * src/backend/storage/buffer/lsm.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "storage/lsm.h"
+#include "storage/shmem.h"
+
+char *LsmLogBlocks;
+
+/*
+ * Initialize LSM log blocks
+ */
+void
+InitLsmLogBlocks(void)
+{
+ bool foundBufs;
+ LsmLogBlocks = (char *)
+ ShmemInitStruct("LSM Log Blocks",
+ NBuffers * (Size) LSM_LOG_BLOCKSZ, &foundBufs);
+}

src/include/storage/lsm.h

@@ -10,6 +10,8 @@
 
 #include "c.h"
 
+extern PGDLLIMPORT int NBuffers;
+
 /*
  * The log file contents are a sequence of 32KB blocks.
  * The only exception is that the tail of the file may contain a partial block.
@@ -39,3 +41,8 @@ typedef struct
 } LsmLogRecord;
 
 #endif /* LSM_H */
+
+/*
+ * prototypes for functions in lsm.c
+ */
+extern void InitLsmLogBlocks(void);