[fix](memtable-limiter) do not block write if load mem usage is low (a…

…pache#28602) Co-authored-by: Yongqiang YANG <98214048+dataroaring@users.noreply.github.com>
seawinde · Dec 19, 2023 · 1253ed0 · 1253ed0
1 parent 9434ee5
commit 1253ed0
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Showing 4 changed files with 18 additions and 2 deletions.
diff --git a/be/src/common/config.cpp b/be/src/common/config.cpp
@@ -602,6 +602,10 @@ DEFINE_Int32(load_process_max_memory_limit_percent, "50"); // 50%
 // might avoid all load jobs hang at the same time.
 DEFINE_Int32(load_process_soft_mem_limit_percent, "80");
 
+// If load memory consumption is within load_process_safe_mem_permit_percent,
+// memtable memory limiter will do nothing.
+DEFINE_Int32(load_process_safe_mem_permit_percent, "5");
+
 // result buffer cancelled time (unit: second)
 DEFINE_mInt32(result_buffer_cancelled_interval_time, "300");
 

diff --git a/be/src/common/config.h b/be/src/common/config.h
@@ -661,6 +661,10 @@ DECLARE_Int32(load_process_max_memory_limit_percent); // 50%
 // might avoid all load jobs hang at the same time.
 DECLARE_Int32(load_process_soft_mem_limit_percent);
 
+// If load memory consumption is within load_process_safe_mem_permit_percent,
+// memtable memory limiter will do nothing.
+DECLARE_Int32(load_process_safe_mem_permit_percent);
+
 // result buffer cancelled time (unit: second)
 DECLARE_mInt32(result_buffer_cancelled_interval_time);
 

diff --git a/be/src/olap/memtable_memory_limiter.cpp b/be/src/olap/memtable_memory_limiter.cpp
@@ -59,6 +59,8 @@ MemTableMemoryLimiter::~MemTableMemoryLimiter() {
 Status MemTableMemoryLimiter::init(int64_t process_mem_limit) {
     _load_hard_mem_limit = calc_process_max_load_memory(process_mem_limit);
     _load_soft_mem_limit = _load_hard_mem_limit * config::load_process_soft_mem_limit_percent / 100;
+    _load_safe_mem_permit =
+            _load_hard_mem_limit * config::load_process_safe_mem_permit_percent / 100;
     g_load_hard_mem_limit.set_value(_load_hard_mem_limit);
     g_load_soft_mem_limit.set_value(_load_soft_mem_limit);
     _mem_tracker = std::make_unique<MemTrackerLimiter>(MemTrackerLimiter::Type::LOAD,
@@ -97,10 +99,14 @@ bool MemTableMemoryLimiter::_hard_limit_reached() {
            _proc_mem_extra() >= 0;
 }
 
+bool MemTableMemoryLimiter::_load_usage_low() {
+    return _mem_tracker->consumption() <= _load_safe_mem_permit;
+}
+
 void MemTableMemoryLimiter::handle_memtable_flush() {
     // Check the soft limit.
     DCHECK(_load_soft_mem_limit > 0);
-    if (!_soft_limit_reached()) {
+    if (!_soft_limit_reached() || _load_usage_low()) {
         return;
     }
     MonotonicStopWatch timer;
@@ -243,4 +249,4 @@ void MemTableMemoryLimiter::_refresh_mem_tracker() {
     }
 }
 
-} // namespace doris
+} // namespace doris
diff --git a/be/src/olap/memtable_memory_limiter.h b/be/src/olap/memtable_memory_limiter.h
@@ -54,6 +54,7 @@ class MemTableMemoryLimiter {
 
     bool _soft_limit_reached();
     bool _hard_limit_reached();
+    bool _load_usage_low();
     void _flush_active_memtables(int64_t need_flush);
     int64_t _flush_memtable(std::weak_ptr<MemTableWriter> writer_to_flush, int64_t threshold);
     void _refresh_mem_tracker();
@@ -68,6 +69,7 @@ class MemTableMemoryLimiter {
     std::unique_ptr<MemTrackerLimiter> _mem_tracker;
     int64_t _load_hard_mem_limit = -1;
     int64_t _load_soft_mem_limit = -1;
+    int64_t _load_safe_mem_permit = -1;
 
     std::vector<std::weak_ptr<MemTableWriter>> _writers;
     std::vector<std::weak_ptr<MemTableWriter>> _active_writers;