From 45b35eaf977430a8fda304c0054eb0f5efb3a96e Mon Sep 17 00:00:00 2001
From: chenlinfeng <723609220@qq.com>
Date: Mon, 18 Oct 2021 11:23:20 +0800
Subject: [PATCH] =?UTF-8?q?=E7=A6=81=E6=AD=A2=E5=A4=9A=E5=8C=BA=E9=97=B4?=
 =?UTF-8?q?=E5=88=87=E5=88=86?=
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---
 sql/handler.cc                            |  1 +
 storage/innobase/handler/handler0alter.cc | 10 +++++-----
 storage/innobase/include/row0pread.h      |  5 ++++-
 storage/innobase/row/row0pread.cc         |  2 +-
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/sql/handler.cc b/sql/handler.cc
index e283ef34cc9f..a22a51a78e83 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -6376,6 +6376,7 @@ int handler::multi_range_read_init(RANGE_SEQ_IF *seq_funcs,
   DBUG_TRACE;
   mrr_iter = seq_funcs->init(seq_init_param, n_ranges, mode);
   mrr_funcs = *seq_funcs;
+  ranges_in_seq = n_ranges;
   mrr_is_output_sorted = mode & HA_MRR_SORTED;
   mrr_have_range = false;
   return 0;
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 25e8b935b577..fa90c3b1d1a1 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -1296,7 +1296,7 @@ int ha_innobase::pq_leader_range_select_scan_init(uint keyno, void *&pq_ctx, uin
      config.m_range_errno = range_errno;
      config.m_pcur = pcur;
      config.m_pq_reverse_scan = pq_reverse_scan;
-
+     config.m_is_single_range = ranges_in_seq == 1;
      auto success =
           pq_reader->add_scan(trx, config, nullptr,false);
      pq_reader->snapshot = trx->read_view;
@@ -1416,7 +1416,7 @@ int ha_innobase::pq_leader_ref_init(uint keyno, void *&pq_ctx, uint &n_threads)
   config.m_range_errno = range_errno;
   config.m_pcur = pcur;
   config.m_pq_reverse_scan = pq_reverse_scan;
-
+  config.m_is_single_range = true;
   auto success =
        pq_reader->add_scan(trx, config, nullptr, false);
   pq_reader->snapshot = trx->read_view;
@@ -1509,7 +1509,7 @@ int ha_innobase::pq_leader_scan_init(uint keyno, void *&pq_ctx, uint &n_threads)
   config.m_range_errno = ret;
   config.m_pcur = pcur;
   config.m_pq_reverse_scan = pq_reverse_scan;
-
+  config.m_is_single_range = true;
   auto success =
         pq_reader->add_scan(trx, config, nullptr, false);
   pq_reader->snapshot = trx->read_view;
@@ -1666,7 +1666,7 @@ int ha_innobase::parallel_scan_init(void *&scan_ctx, size_t &num_threads) {
   Parallel_reader::Scan_range full_scan{};
 
   Parallel_reader::Config config(full_scan, m_prebuilt->table->first_index());
-
+  config.m_is_single_range = true;
   dberr_t err =
       adapter->add_scan(trx, config, [=](const Parallel_reader::Ctx *ctx) {
         return (adapter->process_rows(ctx));
@@ -10270,7 +10270,7 @@ int ha_innopart::parallel_scan_init(void *&scan_ctx, size_t &num_threads) {
 
     Parallel_reader::Config config(FULL_SCAN, m_prebuilt->table->first_index(),
                                    0, dd_partitions[i]->number());
-
+    config.m_is_single_range = true;
     dberr_t err =
         adapter->add_scan(trx, config, [=](const Parallel_reader::Ctx *ctx) {
           return (adapter->process_rows(ctx));
diff --git a/storage/innobase/include/row0pread.h b/storage/innobase/include/row0pread.h
index 0ebf957e110a..d581f862a128 100644
--- a/storage/innobase/include/row0pread.h
+++ b/storage/innobase/include/row0pread.h
@@ -184,7 +184,8 @@ class Parallel_reader {
           m_read_ahead(config.m_read_ahead),
           m_range_errno(config.m_range_errno),
           m_pcur(config.m_pcur),
-          m_pq_reverse_scan(config.m_pq_reverse_scan) {}
+          m_pq_reverse_scan(config.m_pq_reverse_scan),
+          m_is_single_range(config.m_is_single_range) {}
 
     ~Config() {
     }
@@ -216,6 +217,8 @@ class Parallel_reader {
     btr_pcur_t *m_pcur{nullptr};
 
     bool m_pq_reverse_scan{false};
+
+    bool m_is_single_range{false};
   };
 
   /** Constructor.
diff --git a/storage/innobase/row/row0pread.cc b/storage/innobase/row/row0pread.cc
index 748706fcc543..dc9cfaea883b 100644
--- a/storage/innobase/row/row0pread.cc
+++ b/storage/innobase/row/row0pread.cc
@@ -1384,7 +1384,7 @@ dberr_t Parallel_reader::Scan_ctx::create_ranges(const Scan_range &scan_range,
 
     page_cur_move_to_next(&page_cursor);
   }
-  if (ranges.size() == 1 && depth == split_level) {
+  if (ranges.size() == 1 && depth == split_level && m_config.m_is_single_range) {
     if (at_leaf) {
       ranges.clear();
       while (!page_cur_is_after_last(&start_page_cursor)) {