add some notes about getMemoryAmount() and `getNumberOfPhysicalCPUC…

…ores()` (#5126) close #5125
pingcap · Jun 10, 2022 · 8a81342 · 8a81342
1 parent 8916afe
commit 8a81342
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Showing 3 changed files with 6 additions and 2 deletions.
diff --git a/dbms/src/Common/getNumberOfPhysicalCPUCores.h b/dbms/src/Common/getNumberOfPhysicalCPUCores.h
@@ -15,4 +15,5 @@
 #pragma once
 
 /// Get number of CPU cores without hyper-threading.
+/// Note: do not support environment under resource isolation mechanism like Docker, CGroup.
 unsigned getNumberOfPhysicalCPUCores();
diff --git a/dbms/src/Storages/DeltaMerge/workload/Handle.h b/dbms/src/Storages/DeltaMerge/workload/Handle.h
@@ -51,14 +51,16 @@ class HandleLock
 
     std::vector<std::unique_lock<std::recursive_mutex>> getLocks(const std::vector<uint64_t> & handles)
     {
-        std::vector<uint64_t> indexes(handles.size());
+        std::vector<uint64_t> indexes;
+        indexes.reserve(handles.size());
         for (const auto & h : handles)
         {
             indexes.push_back(index(h));
         }
         // Sort mutex indexes to avoid dead lock.
         sort(indexes.begin(), indexes.end());
-        std::vector<std::unique_lock<std::recursive_mutex>> locks(indexes.size());
+        std::vector<std::unique_lock<std::recursive_mutex>> locks;
+        locks.reserve(indexes.size());
         for (auto i : indexes)
         {
             locks.push_back(getLockByIndex(i));

diff --git a/libs/libcommon/include/common/getMemoryAmount.h b/libs/libcommon/include/common/getMemoryAmount.h
@@ -19,5 +19,6 @@
 /**
 * Returns the size of physical memory (RAM) in bytes.
 * Returns 0 on unsupported platform
+* Note: do not support environment under resource isolation mechanism like Docker, CGroup.
 */
 uint64_t getMemoryAmount();