From 283a8f1b4f4941982979234e5a35f295146d9983 Mon Sep 17 00:00:00 2001
From: Kurt Zeilenga <kurt@openldap.org>
Date: Fri, 29 Sep 2000 00:18:29 +0000
Subject: [PATCH] Add dead lock detection thread.

---
 servers/slapd/back-bdb/back-bdb.h |  6 ++++
 servers/slapd/back-bdb/config.c   | 48 ++++++++++++++++++++++++++++++-
 servers/slapd/back-bdb/init.c     | 38 ++++++++++++++++++++----
 3 files changed, 85 insertions(+), 7 deletions(-)

diff --git a/servers/slapd/back-bdb/back-bdb.h b/servers/slapd/back-bdb/back-bdb.h
index 1a80525c2c..0d37f74b89 100644
--- a/servers/slapd/back-bdb/back-bdb.h
+++ b/servers/slapd/back-bdb/back-bdb.h
@@ -73,6 +73,12 @@ struct bdb_info {
 	int			bi_txn_cp;
 	u_int32_t	bi_txn_cp_min;
 	u_int32_t	bi_txn_cp_kbyte;
+
+#ifndef NO_THREADS
+	int			bi_lock_detect;
+	int			bi_lock_detect_seconds;
+	ldap_pvt_thread_t	bi_lock_detect_tid;
+#endif
 };
 #define bi_nextid	bi_databases[BDB_NEXTID]
 #define bi_id2entry	bi_databases[BDB_ID2ENTRY]
diff --git a/servers/slapd/back-bdb/config.c b/servers/slapd/back-bdb/config.c
index f56b8cc2a8..92a872d25c 100644
--- a/servers/slapd/back-bdb/config.c
+++ b/servers/slapd/back-bdb/config.c
@@ -43,7 +43,11 @@ bdb_db_config(
 		bdb->bi_dbenv_home = ch_strdup( argv[1] );
 
 
-	/* mode with which to create new database files */
+	/* transaction checkpoint configuration */
+	} else if ( strcasecmp( argv[0], "dbnosync" ) == 0 ) {
+		bdb->bi_dbenv_xflags |= DB_TXN_NOSYNC;
+
+	/* transaction checkpoint configuration */
 	} else if ( strcasecmp( argv[0], "checkpoint" ) == 0 ) {
 		if ( argc < 3 ) {
 			fprintf( stderr, "%s: line %d: "
@@ -55,6 +59,48 @@ bdb_db_config(
 		bdb->bi_txn_cp_kbyte = strtol( argv[1], NULL, 0 );
 		bdb->bi_txn_cp_min = strtol( argv[2], NULL, 0 );
 
+	/* lock detect configuration */
+	} else if ( strcasecmp( argv[0], "lockdetect" ) == 0 ) {
+#ifndef NO_THREADS
+		if ( argc < 3 ) {
+			fprintf( stderr, "%s: line %d: "
+				"missing parameters in \"lockDetect <policy> <seconds>\" line\n",
+				fname, lineno );
+			return 1;
+		}
+
+		if( strcasecmp( argv[1], "default" ) == 0 ) {
+			bdb->bi_lock_detect = DB_LOCK_DEFAULT;
+
+		} else if( strcasecmp( argv[1], "oldest" ) == 0 ) {
+			bdb->bi_lock_detect = DB_LOCK_OLDEST;
+
+		} else if( strcasecmp( argv[1], "random" ) == 0 ) {
+			bdb->bi_lock_detect = DB_LOCK_RANDOM;
+
+		} else if( strcasecmp( argv[1], "youngest" ) == 0 ) {
+			bdb->bi_lock_detect = DB_LOCK_YOUNGEST;
+
+		} else {
+			fprintf( stderr, "%s: line %d: "
+				"bad policy (%s) in \"lockDetect <policy> <seconds>\" line\n",
+				fname, lineno, argv[1] );
+			return 1;
+		}
+
+		bdb->bi_lock_detect_seconds = strtol( argv[2], NULL, 0 );
+		if( bdb->bi_lock_detect_seconds < 1 ) {
+			fprintf( stderr, "%s: line %d: "
+				"bad seconds (%s) in \"lockDetect <policy> <seconds>\" line\n",
+				fname, lineno, argv[2] );
+			return 1;
+		}
+#else
+		fprintf( stderr, "%s: line %d: "
+			"NO THREADS: lockDetect line ignored\n",
+			fname, lineno );
+#endif
+
 	/* mode with which to create new database files */
 	} else if ( strcasecmp( argv[0], "mode" ) == 0 ) {
 		if ( argc < 2 ) {
diff --git a/servers/slapd/back-bdb/init.c b/servers/slapd/back-bdb/init.c
index 285ccfa18e..2ef9ff4dd2 100644
--- a/servers/slapd/back-bdb/init.c
+++ b/servers/slapd/back-bdb/init.c
@@ -66,10 +66,31 @@ bdb_db_init( BackendDB *be )
 	bdb->bi_dbenv_xflags = 0;
 	bdb->bi_dbenv_mode = DEFAULT_MODE;
 
+	bdb->bi_lock_detect = DB_LOCK_NORUN;
+
 	be->be_private = bdb;
 	return 0;
 }
 
+#ifndef NO_THREADS
+static void *lock_detect_task( void *arg )
+{
+	struct bdb_info *bdb = (struct bdb_info *) arg;
+
+	while( bdb->bi_dbenv != NULL ) {
+		int rc;
+		sleep( bdb->bi_lock_detect_seconds );
+
+		rc = lock_detect( bdb->bi_dbenv, DB_LOCK_CONFLICT, bdb->bi_lock_detect, NULL );
+		if( rc != 0 ) {
+			break;
+		}
+	}
+
+	return NULL;
+}
+#endif
+
 static int
 bdb_db_open( BackendDB *be )
 {
@@ -91,13 +112,11 @@ bdb_db_open( BackendDB *be )
 		return rc;
 	}
 
-	flags = DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN |
-		DB_CREATE | DB_RECOVER | DB_THREAD;
+	flags = DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN | 
+		DB_CREATE | DB_RECOVER;
 
-#ifdef SLAPD_BDB_PRIVATE
-	flags |= DB_PRIVATE;
-#else
-	flags |= DB_INIT_MPOOL;
+#ifndef NO_THREADS
+	flags |= DB_THREAD;
 #endif
 
 	bdb->bi_dbenv->set_errpfx( bdb->bi_dbenv, be->be_suffix[0] );
@@ -195,6 +214,13 @@ bdb_db_open( BackendDB *be )
 	/* <insert> open (and create) index databases */
 
 
+#ifndef NO_THREADS
+	if( bdb->bi_lock_detect != DB_LOCK_NORUN ) {
+		/* listener as a separate THREAD */
+		rc = ldap_pvt_thread_create( &bdb->bi_lock_detect_tid,
+			1, lock_detect_task, bdb );
+	}
+#endif
 	return 0;
 }
 
-- 
2.39.5