[iotdb] branch fix-compaction-tmp-error updated: optimize the way of counting open file handler

[marklau99]

This is an automated email from the ASF dual-hosted git repository.

marklau99 pushed a commit to branch fix-compaction-tmp-error
in repository https://gitbox.apache.org/repos/asf/iotdb.git


The following commit(s) were added to refs/heads/fix-compaction-tmp-error by 
this push:
     new 34d38b0d8c0 optimize the way of counting open file handler
34d38b0d8c0 is described below

commit 34d38b0d8c08264aa80bd2384a6761355c656515
Author: Liu Xuxin <liuxu...@outlook.com>
AuthorDate: Fri Apr 28 17:14:11 2023 +0800

    optimize the way of counting open file handler
---
 .../iotdb/db/service/metrics/FileMetrics.java      | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git 
a/server/src/main/java/org/apache/iotdb/db/service/metrics/FileMetrics.java 
b/server/src/main/java/org/apache/iotdb/db/service/metrics/FileMetrics.java
index 483c2b7345b..55e27148e27 100644
--- a/server/src/main/java/org/apache/iotdb/db/service/metrics/FileMetrics.java
+++ b/server/src/main/java/org/apache/iotdb/db/service/metrics/FileMetrics.java
@@ -35,6 +35,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.BufferedReader;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
 
@@ -47,6 +48,11 @@ public class FileMetrics implements IMetricSet {
   private static final WALManager WAL_MANAGER = WALManager.getInstance();
   private final Runtime runtime = Runtime.getRuntime();
   private String[] getOpenFileNumberCommand;
+  private String fileHandlerCntPath = "/proc/%s/fd";
+
+  public FileMetrics() {
+    fileHandlerCntPath = String.format(fileHandlerCntPath, 
METRIC_CONFIG.getPid());
+  }
 
   @Override
   public void bindTo(AbstractMetricService metricService) {
@@ -245,9 +251,17 @@ public class FileMetrics implements IMetricSet {
   }
 
   private long getOpenFileHandlersNumber() {
+    long fdCount = 0;
     try {
-      if ((METRIC_CONFIG.getSystemType() == SystemType.LINUX
-              || METRIC_CONFIG.getSystemType() == SystemType.MAC)
+      if (METRIC_CONFIG.getSystemType() == SystemType.LINUX) {
+        // count the fd in the system directory instead of
+        // calling runtime.exec() which could be much slower
+        File fdDir = new File(fileHandlerCntPath);
+        if (fdDir.exists()) {
+          File[] fds = fdDir.listFiles();
+          fdCount = fds == null ? 0 : fds.length;
+        }
+      } else if ((METRIC_CONFIG.getSystemType() == SystemType.MAC)
           && METRIC_CONFIG.getPid().length() != 0) {
         Process process = runtime.exec(getOpenFileNumberCommand);
         StringBuilder result = new StringBuilder();
@@ -258,11 +272,11 @@ public class FileMetrics implements IMetricSet {
             result.append(line);
           }
         }
-        return Long.parseLong(result.toString().trim());
+        fdCount = Long.parseLong(result.toString().trim());
       }
     } catch (IOException e) {
       LOGGER.warn("Failed to get open file number, because ", e);
     }
-    return 0L;
+    return fdCount;
   }
 }