Storages: Fix queries with no segment get stuck (#9110) (#9112)

close #9108 If segment count of a query is zero, finishing it directly. And do not add it to the sheduler. Signed-off-by: JaySon-Huang <tshent@qq.com> Co-authored-by: jinhelin <linjinhe33@gmail.com> Co-authored-by: JaySon-Huang <tshent@qq.com>
pingcap · May 31, 2024 · c5885bb · c5885bb
1 parent 61348e8
commit c5885bb
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 12 deletions.
diff --git a/dbms/src/Storages/DeltaMerge/ReadThread/SegmentReadTaskScheduler.cpp b/dbms/src/Storages/DeltaMerge/ReadThread/SegmentReadTaskScheduler.cpp
@@ -32,6 +32,10 @@ SegmentReadTaskScheduler::~SegmentReadTaskScheduler()
 
 void SegmentReadTaskScheduler::add(const SegmentReadTaskPoolPtr & pool)
 {
+    if (pool->getTasks().empty())
+    {
+        return;
+    }
     Stopwatch sw_add;
     std::lock_guard lock(mtx);
     Stopwatch sw_do_add;

diff --git a/dbms/src/Storages/DeltaMerge/SegmentReadTaskPool.h b/dbms/src/Storages/DeltaMerge/SegmentReadTaskPool.h
@@ -191,7 +191,12 @@ class SegmentReadTaskPool : private boost::noncopyable
         // Limiting the minimum number of reading segments to 2 is to avoid, as much as possible,
         // situations where the computation may be faster and the storage layer may not be able to keep up.
         , active_segment_limit(std::max(num_streams_, 2))
-    {}
+    {
+        if (tasks_wrapper.empty())
+        {
+            q.finish();
+        }
+    }
 
     ~SegmentReadTaskPool()
     {
@@ -201,17 +206,17 @@ class SegmentReadTaskPool : private boost::noncopyable
         auto total_bytes = blk_stat.totalBytes();
         auto blk_avg_bytes = total_count > 0 ? total_bytes / total_count : 0;
         auto approximate_max_pending_block_bytes = blk_avg_bytes * max_queue_size;
-        LOG_DEBUG(log, "Done. pool_id={} table_id={} pop={} pop_empty={} pop_empty_ratio={} max_queue_size={} blk_avg_bytes={} approximate_max_pending_block_bytes={:.2f}MB total_count={} total_bytes={:.2f}MB", //
-                  pool_id,
-                  table_id,
-                  pop_times,
-                  pop_empty_times,
-                  pop_empty_ratio,
-                  max_queue_size,
-                  blk_avg_bytes,
-                  approximate_max_pending_block_bytes / 1024.0 / 1024.0,
-                  total_count,
-                  total_bytes / 1024.0 / 1024.0);
+        LOG_INFO(log, "Done. pool_id={} table_id={} pop={} pop_empty={} pop_empty_ratio={} max_queue_size={} blk_avg_bytes={} approximate_max_pending_block_bytes={:.2f}MB total_count={} total_bytes={:.2f}MB", //
+                 pool_id,
+                 table_id,
+                 pop_times,
+                 pop_empty_times,
+                 pop_empty_ratio,
+                 max_queue_size,
+                 blk_avg_bytes,
+                 approximate_max_pending_block_bytes / 1024.0 / 1024.0,
+                 total_count,
+                 total_bytes / 1024.0 / 1024.0);
     }
 
     SegmentReadTaskPtr nextTask();