From c206691cd621378a03ba4c255699b14b2cef82d6 Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org>
Date: Tue, 17 Mar 2020 08:41:40 +0200
Subject: Improve fetchkeys

The new option -b instructs it to fetch only the bucket for each given
key without fetching the actual value, thus eliminating the imact of
non-cached reads.
* src/benchmark.mk.in: Pass FETCHKEYSOPT to fetchkeys.
* src/fetchkeys.c: New option -b: read the bucket, don't fetch value
---
 src/benchmark.mk.in |  2 +-
 src/fetchkeys.c     | 49 +++++++++++++++++++++++++++++++++++++------------
 2 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/src/benchmark.mk.in b/src/benchmark.mk.in
index 5e02f11..43c605c 100644
--- a/src/benchmark.mk.in
+++ b/src/benchmark.mk.in
@@ -30,7 +30,7 @@ test: master.log newcache.log
                                            -e 's/\.$$//' \
                                            -e 'p}') + 100))} \
 			--log-file=$*.log \
-		$(abs_top_builddir)/src/$*/fetchkeys
+		$(abs_top_builddir)/src/$*/fetchkeys $(FETCHKEYSOPT)
 clean:
 	rm -f master.log newcache.log
 allclean: clean
diff --git a/src/fetchkeys.c b/src/fetchkeys.c
index 32f0199..a655a0d 100644
--- a/src/fetchkeys.c
+++ b/src/fetchkeys.c
@@ -9,6 +9,7 @@
 #include <assert.h>
 #include <sys/time.h>
 #include <sys/stat.h>
+#include "gdbmdefs.h"
 
 static unsigned long
 get_size (char const *str)
@@ -185,11 +186,16 @@ main (int argc, char **argv)
   int flags = 0;
   struct timeval t_start, t_open, t_now, td;
   char *keystr;
+  int b_opt = 0;
   
-  while ((i = getopt (argc, argv, "c:t:nTpv")) != EOF)
+  while ((i = getopt (argc, argv, "bc:t:nTpv")) != EOF)
     {
       switch (i)
 	{
+	case 'b':
+	  b_opt = 1;
+	  break;
+	  
 	case 'n':
 	  flags |= GDBM_NOMMAP;
 	  break;
@@ -279,24 +285,43 @@ main (int argc, char **argv)
       
       key.dptr = keystr;
       key.dsize = strlen (key.dptr);
-      data = gdbm_fetch (dbf, key);
-      if (data.dptr == NULL)
+      if (b_opt)
+	{
+	  int    new_hash_val;          /* Computed hash value for the key */
+	  int    bucket_dir;            /* Number of the bucket in directory. */
+	  int    elem_loc;		/* The location in the bucket. */
+	  _gdbm_hash_key (dbf, key, &new_hash_val, &bucket_dir, &elem_loc);
+	  if (_gdbm_get_bucket (dbf, bucket_dir))
+	    {
+	      status = 2;
+	      fprintf (stderr, "%s: error: %s\n", keystr,
+		       gdbm_strerror (gdbm_errno));
+	    }
+	}
+      else
 	{
-	  status = 2;
-	  if (gdbm_errno == GDBM_ITEM_NOT_FOUND)
+	  data = gdbm_fetch (dbf, key);
+	  if (data.dptr == NULL)
 	    {
-	      fprintf (stderr, "%s: not found\n", keystr);
+	      status = 2;
+	      if (gdbm_errno == GDBM_ITEM_NOT_FOUND)
+		{
+		  fprintf (stderr, "%s: not found\n", keystr);
+		}
+	      else
+		{
+		  fprintf (stderr, "%s: error: %s\n", keystr,
+			   gdbm_strerror (gdbm_errno));
+		}
 	    }
 	  else
 	    {
-	      fprintf (stderr, "%s: error: %s\n", keystr,
-		       gdbm_strerror (gdbm_errno));
+	      if (print)
+		printf ("%s: %*.*s\n", keystr,
+			data.dsize, data.dsize, data.dptr);
+	      free (data.dptr);
 	    }
-	  continue;
 	}
-      if (print)
-	printf ("%s: %*.*s\n", keystr, data.dsize, data.dsize, data.dptr);
-      free (data.dptr);
     }
   gdbm_close (dbf);
   if (verbose)
-- 
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