Merge pull request #3660 from vespa-engine/vekterli/log-with-backtrace-on-empty-bucketdb-update

Log with backtrace when inserting an empty bucket into the database

1 files changed, 18 insertions, 0 deletions

diff --git a/storage/src/vespa/storage/bucketdb/mapbucketdatabase.cpp b/storage/src/vespa/storage/bucketdb/mapbucketdatabase.cpp
index fbc2b6d348f..5ac4c4b1ee7 100644
--- a/storage/src/vespa/storage/bucketdb/mapbucketdatabase.cpp
+++ b/storage/src/vespa/storage/bucketdb/mapbucketdatabase.cpp
@@ -2,8 +2,12 @@
 
 #include "mapbucketdatabase.h"
 #include <vespa/storage/common/bucketoperationlogger.h>
+#include <vespa/vespalib/util/backtrace.h>
 #include <ostream>
 
+#include <vespa/log/bufferedlogger.h>
+LOG_SETUP(".mapbucketdatabase");
+
 namespace storage {
 
 MapBucketDatabase::MapBucketDatabase()
@@ -136,10 +140,24 @@ MapBucketDatabase::remove(const document::BucketId& bucket)
     remove(0, 0, bucket);
 }
 
+namespace {
+
+void __attribute__((noinline)) log_empty_bucket_insertion(const document::BucketId& id) {
+    // Use buffered logging to avoid spamming the logs in case this is triggered for
+    // many buckets simultaneously.
+    LOGBP(error, "Inserted empty bucket %s into database.\n%s",
+          id.toString().c_str(), vespalib::getStackTrace(2).c_str());
+}
+
+}
+
 void
 MapBucketDatabase::update(const Entry& newEntry)
 {
     assert(newEntry.valid());
+    if (newEntry->getNodeCount() == 0) {
+        log_empty_bucket_insertion(newEntry.getBucketId());
+    }
     LOG_BUCKET_OPERATION_NO_LOCK(
             newEntry.getBucketId(),
             vespalib::make_string(