recover the lines of clearing read buffer that I accidentally removed.

Author: Tianyi Chen

src/network/connection_handle.cpp

@@ -204,6 +204,26 @@ Transition ConnectionHandle::FillReadBuffer() {
   Transition result = Transition::NEED_DATA;
   ssize_t bytes_read = 0;
   bool done = false;
+  
+  // reset buffer if all the contents have been read
+  if (rbuf_->buf_ptr == rbuf_->buf_size) rbuf_->Reset();
+
+  // buf_ptr shouldn't overflow
+  PL_ASSERT(rbuf_->buf_ptr <= rbuf_->buf_size);
+
+  /* Do we have leftover data and are we at the end of the buffer?
+   * Move the data to the head of the buffer and clear out all the old data
+   * Note: The assumption here is that all the packets/headers till
+   *  rbuf_.buf_ptr have been fully processed
+   */
+  if (rbuf_->buf_ptr < rbuf_->buf_size && rbuf_->buf_size == rbuf_->GetMaxSize()) {
+    auto unprocessed_len = rbuf_->buf_size - rbuf_->buf_ptr;
+    // Move this data to the head of rbuf_1
+    std::memmove(rbuf_->GetPtr(0), rbuf_->GetPtr(rbuf_->buf_ptr), unprocessed_len);
+    // update pointers
+    rbuf_->buf_ptr = 0;
+    rbuf_->buf_size = unprocessed_len;
+  }
 
   // return explicitly
   while (done == false) {

test/network/select_all_test.cpp

@@ -54,15 +54,15 @@ void *SelectAllTest(int port) {
     txn1.commit();
 
     pqxx::work txn2(C);
-    for (int i = 0; i < 20; i++) {
+    for (int i = 0; i < 2000; i++) {
       std::string s = "INSERT INTO template VALUES (" + std::to_string(i) + ")";
       LOG_INFO("Start sending query");
       txn2.exec(s);
     }
 
     pqxx::result R = txn2.exec("SELECT * from template;");
     txn2.commit();
-    EXPECT_EQ(R.size(), 20);
+    EXPECT_EQ(R.size(), 2000);
   } catch (const std::exception &e) {
     LOG_INFO("[SelectAllTest] Exception occurred: %s", e.what());
     EXPECT_TRUE(false);

test/network/ssl_test.cpp

@@ -73,15 +73,15 @@ void *BasicTest(int port) {
     txn3.commit();
 
     pqxx::work txn4(C);
-    for (int i = 0; i < 10; i++) {
+    for (int i = 0; i < 1000; i++) {
       std::string s = "INSERT INTO template VALUES (" + std::to_string(i) + ")";
       txn4.exec(s);
     }
 
     R = txn4.exec("SELECT * from template;");
     txn4.commit();
 
-    EXPECT_EQ(R.size(), 10);
+    EXPECT_EQ(R.size(), 1000);
 
   } catch (const std::exception &e) {
     LOG_INFO("[SSLTest] Exception occurred: %s", e.what());