r19685: Two changes inspired by problems with huge tdbs. tdbtool's list command now

prints the hash on every record for easier awk'ing, and tdbbackup allows a
different hash chain length on the backed up tdb.

Jeremy, Günther, this might be interesting for you huge domains. Not only
locking.tdb, also the winbind ones might grow huge.

In the installation I fixed with this winbind spent a huge amount of CPU
spinning through a degenerated winbindd_idmap.tdb with entries for more than
15.000 users. With a default number of hash chains of 131 on that tdb you can
imagine that the lists get large.

Not merging to 4, I don't get tdbbackup to compile there right now.

What about changing the global default hash chain number to be dramatically
larger? Disk is cheap these days.

Volker
(This used to be commit 577d0ff658596f8246f120e0342cc5c9e4077ece)

1 files changed, 7 insertions, 2 deletions

diff --git a/source3/tdb/tools/tdbbackup.c b/source3/tdb/tools/tdbbackup.c
index f49cd339c7..4ae5a4f921 100644
--- a/source3/tdb/tools/tdbbackup.c
+++ b/source3/tdb/tools/tdbbackup.c
@@ -93,6 +93,7 @@ static void usage(void)
 	printf("   -h            this help message\n");
 	printf("   -s suffix     set the backup suffix\n");
 	printf("   -v            verify mode (restore if corrupt)\n");
+	printf("   -n hashsize   set the new hash size for the backup\n");
 }
 		
 
@@ -102,9 +103,10 @@ static void usage(void)
 	int ret = 0;
 	int c;
 	int verify = 0;
+	int hashsize = 0;
 	const char *suffix = ".bak";
 
-	while ((c = getopt(argc, argv, "vhs:")) != -1) {
+	while ((c = getopt(argc, argv, "vhs:n:")) != -1) {
 		switch (c) {
 		case 'h':
 			usage();
@@ -115,6 +117,9 @@ static void usage(void)
 		case 's':
 			suffix = optarg;
 			break;
+		case 'n':
+			hashsize = atoi(optarg);
+			break;
 		}
 	}
 
@@ -138,7 +143,7 @@ static void usage(void)
 			}
 		} else {
 			if (file_newer(fname, bak_name) &&
-			    backup_tdb(fname, bak_name) != 0) {
+			    backup_tdb(fname, bak_name, hashsize) != 0) {
 				ret = 1;
 			}
 		}