feat(buffer): integrate IVF and DiskANN with shared page cache

src/ailego/buffer/vector_page_table.cc

@@ -993,6 +993,18 @@ VecBufferPool::VecBufferPool(const std::string &filename, bool writable) {
 #endif
     throw std::runtime_error("Failed to stat file: " + filename);
   }
+#if !defined(_MSC_VER)
+  // Atomic replacement between the two opens must not mix metadata from one
+  // file with pages from another. Windows CRT opens prevent deletion while
+  // either descriptor is live; POSIX needs an explicit identity check.
+  struct stat meta_st;
+  if (fstat(meta_fd_, &meta_st) < 0 || st.st_dev != meta_st.st_dev ||
+      st.st_ino != meta_st.st_ino) {
+    ::close(fd_);
+    ::close(meta_fd_);
+    throw std::runtime_error("Backing file changed while opening: " + filename);
+  }
+#endif
   file_size_ = st.st_size;
   initial_file_size_ = file_size_;
 #if defined(__linux__) && !defined(__ANDROID__)

src/ailego/io/libaio_loader.h

@@ -54,8 +54,12 @@ typedef int (*aio_getevents_fn)(io_context_t ctx, long min_nr, long nr,
 class LibAioLoader {
  public:
   static LibAioLoader &Instance() {
-    static LibAioLoader instance;
-    return instance;
+    // Global thread pools may join workers during static destruction, after
+    // this loader would be destroyed. Their thread-local AIO contexts still
+    // need io_destroy(), so retain the loader and library until process exit.
+    // Individual AIO contexts must still be destroyed by their owners.
+    static LibAioLoader *const instance = new LibAioLoader();
+    return *instance;
   }
 
   // Load (or confirm already loaded) libaio.  Returns true on success.

src/core/algorithm/diskann/diskann_context.cc

@@ -85,7 +85,8 @@ int DiskAnnContext::resize_fetch_sector_buffer(
 }
 
 int DiskAnnContext::init(ContextType type, uint32_t /*graph_degree*/,
-                         uint32_t pq_chunk_num, uint32_t element_size) {
+                         uint32_t pq_chunk_num, uint32_t element_size,
+                         bool setup_io_context) {
   if (!entity_ || element_size == 0) {
     LOG_ERROR("Invalid DiskAnn context parameters");
     return IndexError_InvalidArgument;
@@ -137,10 +138,12 @@ int DiskAnnContext::init(ContextType type, uint32_t /*graph_degree*/,
         return IndexError_NoMemory;
       }
 
-      ret = setup_io_ctx(io_ctx_);
-      if (ret != 0) {
-        LOG_ERROR("setup io ctx error, ret=%d", ret);
-        return ret;
+      if (setup_io_context) {
+        ret = setup_io_ctx(io_ctx_);
+        if (ret != 0) {
+          LOG_ERROR("setup io ctx error, ret=%d", ret);
+          return ret;
+        }
       }
       break;
 
@@ -150,10 +153,12 @@ int DiskAnnContext::init(ContextType type, uint32_t /*graph_degree*/,
         return ret;
       }
 
-      ret = setup_io_ctx(io_ctx_);
-      if (ret != 0) {
-        LOG_ERROR("setup fetch io ctx error, ret=%d", ret);
-        return ret;
+      if (setup_io_context) {
+        ret = setup_io_ctx(io_ctx_);
+        if (ret != 0) {
+          LOG_ERROR("setup fetch io ctx error, ret=%d", ret);
+          return ret;
+        }
       }
       break;
 

src/core/algorithm/diskann/diskann_context.h

@@ -67,7 +67,7 @@ class DiskAnnContext : public IndexContext,
  public:
   //! Init
   int init(ContextType type, uint32_t graph_degree, uint32_t pq_chunk_num,
-           uint32_t element_size);
+           uint32_t element_size, bool setup_io_context = true);
 
   //! Update context, the context may be shared by different searcher/streamer
   int update_context(ContextType type, const IndexMeta &meta,