SERVER-29465 Add warning about Windows SystemFileCacheSize for WiredTiger

9 files changed, 80 insertions, 0 deletions

diff --git a/src/mongo/db/startup_warnings_mongod.cpp b/src/mongo/db/startup_warnings_mongod.cpp
index a15bf056428..6f0c42263f3 100644
--- a/src/mongo/db/startup_warnings_mongod.cpp
+++ b/src/mongo/db/startup_warnings_mongod.cpp
@@ -369,6 +369,23 @@ void logMongodStartupWarnings(const StorageGlobalParams& storageParams,
         warned = true;
     }
 
+    if (storageParams.engine == "wiredTiger") {
+        // If the filesystemMaxCacheSize / totalMemorySize > 0.4, we should raise this
+        // warning because it leads to terrible performance for WiredTiger
+        const double filesystemCachePercentageThreshold = 0.4;
+        if (p.getMaxSystemFileCachePercentage() > filesystemCachePercentageThreshold) {
+            log() << startupWarningsLog;
+            log()
+                << "** WARNING: The file system cache of this machine is configured to be greater "
+                << "than " << 100 * filesystemCachePercentageThreshold << "% of the total memory. "
+                << "This can lead to increased memory pressure and poor performance."
+                << startupWarningsLog;
+            log() << "See http://dochub.mongodb.org/core/wt-windows-system-file-cache"
+                  << startupWarningsLog;
+            warned = true;
+        }
+    }
+
 #endif  // #ifdef _WIN32
 
     if (storageParams.engine == "ephemeralForTest") {
diff --git a/src/mongo/util/processinfo.h b/src/mongo/util/processinfo.h
index f44ef37799a..0a2d2cc1d22 100644
--- a/src/mongo/util/processinfo.h
+++ b/src/mongo/util/processinfo.h
@@ -157,6 +157,12 @@ public:
     static bool blockInMemory(const void* start);
 
     /**
+     * Returns a positive floating point number between 0.0 and 1.0 that
+     * reflects the maximum percentage of RAM the filesystem cache is allowed to grow.
+     */
+    static double getMaxSystemFileCachePercentage();
+
+    /**
      * Returns a positive floating point number between 0.0 and 1.0 to inform MMapV1 how much it
      * must remap pages to bring the system page file implementation back below a certain
      * threshold. A number of 1.0 means remap everything.
diff --git a/src/mongo/util/processinfo_freebsd.cpp b/src/mongo/util/processinfo_freebsd.cpp
index d9bf1aa72fd..ce07c514753 100644
--- a/src/mongo/util/processinfo_freebsd.cpp
+++ b/src/mongo/util/processinfo_freebsd.cpp
@@ -120,6 +120,10 @@ int ProcessInfo::getResidentSize() {
     return rss;
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_linux.cpp b/src/mongo/util/processinfo_linux.cpp
index c2813b026b0..a3310e64e95 100644
--- a/src/mongo/util/processinfo_linux.cpp
+++ b/src/mongo/util/processinfo_linux.cpp
@@ -451,6 +451,10 @@ int ProcessInfo::getResidentSize() {
     return (int)((p.getResidentSizeInPages() * getPageSize()) / (1024.0 * 1024));
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_openbsd.cpp b/src/mongo/util/processinfo_openbsd.cpp
index dc3e43d8636..a4c1d0f9ab2 100644
--- a/src/mongo/util/processinfo_openbsd.cpp
+++ b/src/mongo/util/processinfo_openbsd.cpp
@@ -130,6 +130,10 @@ int ProcessInfo::getResidentSize() {
     return rss;
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_osx.cpp b/src/mongo/util/processinfo_osx.cpp
index c82aa3f9411..475016de313 100644
--- a/src/mongo/util/processinfo_osx.cpp
+++ b/src/mongo/util/processinfo_osx.cpp
@@ -118,6 +118,10 @@ int ProcessInfo::getResidentSize() {
     return (int)(ti.resident_size / (1024 * 1024));
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_solaris.cpp b/src/mongo/util/processinfo_solaris.cpp
index c8a7110e738..3bd892de4e8 100644
--- a/src/mongo/util/processinfo_solaris.cpp
+++ b/src/mongo/util/processinfo_solaris.cpp
@@ -127,6 +127,10 @@ int ProcessInfo::getResidentSize() {
     return static_cast<int>(p.psinfo.pr_rssize / 1024);
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_unknown.cpp b/src/mongo/util/processinfo_unknown.cpp
index 8984012b13c..a8960e27de0 100644
--- a/src/mongo/util/processinfo_unknown.cpp
+++ b/src/mongo/util/processinfo_unknown.cpp
@@ -53,6 +53,10 @@ int ProcessInfo::getResidentSize() {
     return -1;
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    return 0.0;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     return 0.0;
 }
diff --git a/src/mongo/util/processinfo_windows.cpp b/src/mongo/util/processinfo_windows.cpp
index 06c81b2e0f8..676204c9856 100644
--- a/src/mongo/util/processinfo_windows.cpp
+++ b/src/mongo/util/processinfo_windows.cpp
@@ -119,6 +119,39 @@ int ProcessInfo::getResidentSize() {
     return _wconvertmtos(pmc.WorkingSetSize);
 }
 
+double ProcessInfo::getMaxSystemFileCachePercentage() {
+    SIZE_T minCacheSize = 0;
+    SIZE_T maxCacheSize = 0;
+    DWORD flags = 0;
+    BOOL status = GetSystemFileCacheSize(&minCacheSize, &maxCacheSize, &flags);
+    if (!status) {
+        DWORD gle = GetLastError();
+        severe() << "GetSystemFileCacheSize failed with " << errnoWithDescription(gle);
+        fassertFailed(40667);
+    }
+
+    if (!(flags & FILE_CACHE_MAX_HARD_ENABLE)) {
+        return 1.0;
+    }
+
+    MEMORYSTATUSEX mse;
+    mse.dwLength = sizeof(mse);
+    status = GlobalMemoryStatusEx(&mse);
+    if (!status) {
+        DWORD gle = GetLastError();
+        severe() << "GlobalMemoryStatusEx failed with " << errnoWithDescription(gle);
+        fassertFailed(40668);
+    }
+
+    DWORDLONG totalMemorySize = mse.ullTotalPhys;
+    if (totalMemorySize == 0) {
+        severe() << "Total memory is 0";
+        fassertFailed(40669);
+    }
+
+    return static_cast<double>(maxCacheSize) / totalMemorySize;
+}
+
 double ProcessInfo::getSystemMemoryPressurePercentage() {
     MEMORYSTATUSEX mse;
     mse.dwLength = sizeof(mse);