From cee5a2ecbe92212ee1b3bba2b39069973055069a Mon Sep 17 00:00:00 2001
From: yihaoDeng <luomoxyz@126.com>
Date: Tue, 4 Jan 2022 18:01:31 +0800
Subject: [PATCH] optimize tfile

---
 include/util/tfile.h                          |  2 +-
 .../index/inc/index_fst_counting_writer.h     |  5 +++++
 .../index/src/index_fst_counting_writer.c     | 20 ++++++++++++++++++-
 source/libs/index/test/indexTests.cc          |  2 +-
 source/util/src/tfile.c                       | 10 ++++++++++
 5 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/include/util/tfile.h b/include/util/tfile.h
index b3d141c443..d3813051a4 100644
--- a/include/util/tfile.h
+++ b/include/util/tfile.h
@@ -43,7 +43,7 @@ int32_t tfFsync(int64_t tfd);
 bool    tfValid(int64_t tfd);
 int64_t tfLseek(int64_t tfd, int64_t offset, int32_t whence);
 int32_t tfFtruncate(int64_t tfd, int64_t length);
-
+void *  tfMmapReadOnly(int64_t tfd, int64_t length);
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/index/inc/index_fst_counting_writer.h b/source/libs/index/inc/index_fst_counting_writer.h
index fcc0d5a0b3..d7363f2f4c 100644
--- a/source/libs/index/inc/index_fst_counting_writer.h
+++ b/source/libs/index/inc/index_fst_counting_writer.h
@@ -22,6 +22,8 @@ extern "C" {
 
 #include "tfile.h"
 
+//#define USE_MMAP 1
+
 #define DefaultMem 1024 * 1024
 
 static char tmpFile[] = "./index";
@@ -39,6 +41,9 @@ typedef struct WriterCtx {
       bool readOnly;
       char buf[256];
       int  size;
+#ifdef USE_MMAP
+      char* ptr;
+#endif
     } file;
     struct {
       int32_t capa;
diff --git a/source/libs/index/src/index_fst_counting_writer.c b/source/libs/index/src/index_fst_counting_writer.c
index c3e1aab381..2b64d65e46 100644
--- a/source/libs/index/src/index_fst_counting_writer.c
+++ b/source/libs/index/src/index_fst_counting_writer.c
@@ -31,7 +31,12 @@ static int writeCtxDoWrite(WriterCtx* ctx, uint8_t* buf, int len) {
 static int writeCtxDoRead(WriterCtx* ctx, uint8_t* buf, int len) {
   int nRead = 0;
   if (ctx->type == TFile) {
+#ifdef USE_MMAP
+    nRead = len < ctx->file.size ? len : ctx->file.size;
+    memcpy(buf, ctx->file.ptr, nRead);
+#else
     nRead = tfRead(ctx->file.fd, buf, len);
+#endif
   } else {
     memcpy(buf, ctx->mem.buf + ctx->offset, len);
   }
@@ -43,7 +48,13 @@ static int writeCtxDoReadFrom(WriterCtx* ctx, uint8_t* buf, int len, int32_t off
   int nRead = 0;
   if (ctx->type == TFile) {
     // tfLseek(ctx->file.fd, offset, 0);
+#ifdef USE_MMAP
+    int32_t last = ctx->file.size - offset;
+    nRead = last >= len ? len : last;
+    memcpy(buf, ctx->file.ptr + offset, nRead);
+#else
     nRead = tfPread(ctx->file.fd, buf, len, offset);
+#endif
   } else {
     // refactor later
     assert(0);
@@ -83,6 +94,9 @@ WriterCtx* writerCtxCreate(WriterType type, const char* path, bool readOnly, int
       struct stat fstat;
       stat(path, &fstat);
       ctx->file.size = fstat.st_size;
+#ifdef USE_MMAP
+      ctx->file.ptr = (char*)tfMmapReadOnly(ctx->file.fd, ctx->file.size);
+#endif
     }
     memcpy(ctx->file.buf, path, strlen(path));
     if (ctx->file.fd < 0) {
@@ -111,8 +125,12 @@ void writerCtxDestroy(WriterCtx* ctx, bool remove) {
   if (ctx->type == TMemory) {
     free(ctx->mem.buf);
   } else {
-    // ctx->flush(ctx);
     tfClose(ctx->file.fd);
+    if (ctx->file.readOnly) {
+#ifdef USE_MMAP
+      munmap(ctx->file.ptr, ctx->file.size);
+#endif
+    }
     if (remove) { unlink(ctx->file.buf); }
   }
   free(ctx);
diff --git a/source/libs/index/test/indexTests.cc b/source/libs/index/test/indexTests.cc
index c3d6e5541f..badc510b19 100644
--- a/source/libs/index/test/indexTests.cc
+++ b/source/libs/index/test/indexTests.cc
@@ -28,7 +28,7 @@
 #include "tutil.h"
 using namespace std;
 
-#define NUM_OF_THREAD 10
+#define NUM_OF_THREAD 5
 
 class DebugInfo {
  public:
diff --git a/source/util/src/tfile.c b/source/util/src/tfile.c
index 4cb20802c7..0f68e9204d 100644
--- a/source/util/src/tfile.c
+++ b/source/util/src/tfile.c
@@ -158,3 +158,13 @@ int32_t tfFtruncate(int64_t tfd, int64_t length) {
   taosReleaseRef(tsFileRsetId, tfd);
   return code;
 }
+
+void *tfMmapReadOnly(int64_t tfd, int64_t length) {
+  void *p = taosAcquireRef(tsFileRsetId, tfd);
+  if (p == NULL) return NULL;
+  int32_t fd = (int32_t)(uintptr_t)p;
+
+  void *ptr = mmap(NULL, length, PROT_READ, MAP_SHARED, fd, 0);
+  taosReleaseRef(tsFileRsetId, tfd);
+  return ptr;
+}