--- servers/slapd/overlays/syncprov.c	2010/04/19 16:53:04	1.147.2.73
+++ servers/slapd/overlays/syncprov.c	2007/01/02 19:01:14	1.165
@@ -1,8 +1,8 @@
-/* $OpenLDAP$ */
+/* $OpenLDAP: pkg/ldap/servers/slapd/overlays/syncprov.c,v 1.164 2006/12/02 09:42:42 ando Exp $ */
 /* syncprov.c - syncrepl provider */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 2004-2010 The OpenLDAP Foundation.
+ * Copyright 2004-2007 The OpenLDAP Foundation.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,10 +28,6 @@
 #include "config.h"
 #include "ldap_rq.h"
 
-#ifdef LDAP_DEVEL
-#define	CHECK_CSN	1
-#endif
-
 /* A modify request on a particular entry */
 typedef struct modinst {
 	struct modinst *mi_next;
@@ -48,7 +44,6 @@ typedef struct modtarget {
 /* A queued result of a persistent search */
 typedef struct syncres {
 	struct syncres *s_next;
-	Entry *s_e;
 	struct berval s_dn;
 	struct berval s_ndn;
 	struct berval s_uuid;
@@ -64,7 +59,6 @@ typedef struct syncops {
 	ID		s_eid;		/* entryID of search base */
 	Operation	*s_op;		/* search op */
 	int		s_rid;
-	int		s_sid;
 	struct berval s_filterstr;
 	int		s_flags;	/* search status */
 #define	PS_IS_REFRESHING	0x01
@@ -72,11 +66,12 @@ typedef struct syncops {
 #define	PS_WROTE_BASE		0x04
 #define	PS_FIND_BASE		0x08
 #define	PS_FIX_FILTER		0x10
-#define	PS_TASK_QUEUED		0x20
 
 	int		s_inuse;	/* reference count */
 	struct syncres *s_res;
 	struct syncres *s_restail;
+	struct re_s	*s_qtask;	/* task for playing psearch responses */
+#define	RUNQ_INTERVAL	36000	/* a long time */
 	ldap_pvt_thread_mutex_t	s_mutex;
 } syncops;
 
@@ -108,7 +103,6 @@ typedef struct slog_entry {
 	struct slog_entry *se_next;
 	struct berval se_uuid;
 	struct berval se_csn;
-	int	se_sid;
 	ber_tag_t	se_tag;
 } slog_entry;
 
@@ -124,10 +118,7 @@ typedef struct sessionlog {
 /* The main state for this overlay */
 typedef struct syncprov_info_t {
 	syncops		*si_ops;
-	BerVarray	si_ctxcsn;	/* ldapsync context */
-	struct berval	si_contextdn;
-	int		*si_sids;
-	int		si_numcsns;
+	struct berval	si_ctxcsn;	/* ldapsync context */
 	int		si_chkops;	/* checkpointing info */
 	int		si_chktime;
 	int		si_numops;	/* number of ops since last checkpoint */
@@ -136,31 +127,22 @@ typedef struct syncprov_info_t {
 	time_t	si_chklast;	/* time of last checkpoint */
 	Avlnode	*si_mods;	/* entries being modified */
 	sessionlog	*si_logs;
-	ldap_pvt_thread_rdwr_t	si_csn_rwlock;
+	ldap_pvt_thread_mutex_t	si_csn_mutex;
 	ldap_pvt_thread_mutex_t	si_ops_mutex;
 	ldap_pvt_thread_mutex_t	si_mods_mutex;
-	ldap_pvt_thread_mutex_t	si_resp_mutex;
+	char		si_ctxcsnbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
 } syncprov_info_t;
 
 typedef struct opcookie {
 	slap_overinst *son;
 	syncmatches *smatches;
-	modtarget *smt;
-	Entry *se;
 	struct berval sdn;	/* DN of entry, for deletes */
 	struct berval sndn;
 	struct berval suuid;	/* UUID of entry */
 	struct berval sctxcsn;
-	short osid;	/* sid of op csn */
-	short rsid;	/* sid of relay */
-	short sreference;	/* Is the entry a reference? */
+	int sreference;	/* Is the entry a reference? */
 } opcookie;
 
-typedef struct mutexint {
-	ldap_pvt_thread_mutex_t mi_mutex;
-	int mi_int;
-} mutexint;
-
 typedef struct fbase_cookie {
 	struct berval *fdn;	/* DN of a modified entry, for scope testing */
 	syncops *fss;	/* persistent search we're testing against */
@@ -408,6 +390,9 @@ static struct berval generic_filterstr =
 static int
 syncprov_findbase( Operation *op, fbase_cookie *fc )
 {
+	opcookie *opc = op->o_callback->sc_private;
+	slap_overinst *on = opc->son;
+
 	/* Use basic parameters from syncrepl search, but use
 	 * current op's threadctx / tmpmemctx
 	 */
@@ -423,8 +408,8 @@ syncprov_findbase( Operation *op, fbase_
 
 		fop = *fc->fss->s_op;
 
-		fop.o_bd = fop.o_bd->bd_self;
 		fop.o_hdr = op->o_hdr;
+		fop.o_bd = op->o_bd;
 		fop.o_time = op->o_time;
 		fop.o_tincr = op->o_tincr;
 
@@ -444,7 +429,9 @@ syncprov_findbase( Operation *op, fbase_
 		fop.ors_filter = &generic_filter;
 		fop.ors_filterstr = generic_filterstr;
 
+		fop.o_bd->bd_info = on->on_info->oi_orig;
 		rc = fop.o_bd->be_search( &fop, &frs );
+		fop.o_bd->bd_info = (BackendInfo *)on;
 	} else {
 		ldap_pvt_thread_mutex_unlock( &fc->fss->s_mutex );
 		fc->fbase = 1;
@@ -509,8 +496,7 @@ findmax_cb( Operation *op, SlapReply *rs
 		Attribute *a = attr_find( rs->sr_entry->e_attrs,
 			slap_schema.si_ad_entryCSN );
 
-		if ( a && ber_bvcmp( &a->a_vals[0], maxcsn ) > 0 &&
-			slap_parse_csn_sid( &a->a_vals[0] ) == slap_serverID ) {
+		if ( a && ber_bvcmp( &a->a_vals[0], maxcsn ) > 0 ) {
 			maxcsn->bv_len = a->a_vals[0].bv_len;
 			strcpy( maxcsn->bv_val, a->a_vals[0].bv_val );
 		}
@@ -591,19 +577,26 @@ syncprov_findcsn( Operation *op, find_cs
 	slap_callback cb = {0};
 	Operation fop;
 	SlapReply frs = { REP_RESULT };
-	char buf[LDAP_PVT_CSNSTR_BUFSIZE + STRLENOF("(entryCSN<=)")];
-	char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
+	char buf[LDAP_LUTIL_CSNSTR_BUFSIZE + STRLENOF("(entryCSN<=)")];
+	char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
 	struct berval maxcsn;
-	Filter cf;
-	AttributeAssertion eq = ATTRIBUTEASSERTION_INIT;
+	Filter cf, af;
+#ifdef LDAP_COMP_MATCH
+	AttributeAssertion eq = { NULL, BER_BVNULL, NULL };
+#else
+	AttributeAssertion eq = { NULL, BER_BVNULL };
+#endif
 	fpres_cookie pcookie;
 	sync_control *srs = NULL;
 	struct slap_limits_set fc_limits;
 	int i, rc = LDAP_SUCCESS, findcsn_retry = 1;
-	int maxid;
 
 	if ( mode != FIND_MAXCSN ) {
 		srs = op->o_controls[slap_cids.sc_LDAPsync];
+
+		if ( srs->sr_state.ctxcsn.bv_len >= LDAP_LUTIL_CSNSTR_BUFSIZE ) {
+			return LDAP_OTHER;
+		}
 	}
 
 	fop = *op;
@@ -613,7 +606,6 @@ syncprov_findcsn( Operation *op, find_cs
 
 	cf.f_ava = &eq;
 	cf.f_av_desc = slap_schema.si_ad_entryCSN;
-	BER_BVZERO( &cf.f_av_value );
 	cf.f_next = NULL;
 
 	fop.o_callback = &cb;
@@ -626,61 +618,32 @@ again:
 	switch( mode ) {
 	case FIND_MAXCSN:
 		cf.f_choice = LDAP_FILTER_GE;
-		/* If there are multiple CSNs, use the one with our serverID */
-		for ( i=0; i<si->si_numcsns; i++) {
-			if ( slap_serverID == si->si_sids[i] ) {
-				maxid = i;
-				break;
-			}
-		}
-		if ( i == si->si_numcsns ) {
-			/* No match: this is multimaster, and none of the content in the DB
-			 * originated locally. Treat like no CSN.
-			 */
-			return LDAP_NO_SUCH_OBJECT;
-		}
-		cf.f_av_value = si->si_ctxcsn[maxid];
-		fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
-			"(entryCSN>=%s)", cf.f_av_value.bv_val );
-		if ( fop.ors_filterstr.bv_len >= sizeof( buf ) ) {
-			return LDAP_OTHER;
-		}
+		cf.f_av_value = si->si_ctxcsn;
+		fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN>=%s)",
+			cf.f_av_value.bv_val );
 		fop.ors_attrsonly = 0;
 		fop.ors_attrs = csn_anlist;
 		fop.ors_slimit = SLAP_NO_LIMIT;
 		cb.sc_private = &maxcsn;
 		cb.sc_response = findmax_cb;
-		strcpy( cbuf, cf.f_av_value.bv_val );
+		strcpy( cbuf, si->si_ctxcsn.bv_val );
 		maxcsn.bv_val = cbuf;
-		maxcsn.bv_len = cf.f_av_value.bv_len;
+		maxcsn.bv_len = si->si_ctxcsn.bv_len;
 		break;
 	case FIND_CSN:
-		if ( BER_BVISEMPTY( &cf.f_av_value )) {
-			cf.f_av_value = srs->sr_state.ctxcsn[0];
-			/* If there are multiple CSNs, use the smallest */
-			for ( i=1; i<srs->sr_state.numcsns; i++ ) {
-				if ( ber_bvcmp( &cf.f_av_value, &srs->sr_state.ctxcsn[i] )
-					> 0 ) {
-					cf.f_av_value = srs->sr_state.ctxcsn[i];
-				}
-			}
-		}
+		cf.f_av_value = srs->sr_state.ctxcsn;
 		/* Look for exact match the first time */
 		if ( findcsn_retry ) {
 			cf.f_choice = LDAP_FILTER_EQUALITY;
-			fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
-				"(entryCSN=%s)", cf.f_av_value.bv_val );
+			fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN=%s)",
+				cf.f_av_value.bv_val );
 		/* On retry, look for <= */
 		} else {
 			cf.f_choice = LDAP_FILTER_LE;
 			fop.ors_limit = &fc_limits;
-			memset( &fc_limits, 0, sizeof( fc_limits ));
 			fc_limits.lms_s_unchecked = 1;
-			fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
-				"(entryCSN<=%s)", cf.f_av_value.bv_val );
-		}
-		if ( fop.ors_filterstr.bv_len >= sizeof( buf ) ) {
-			return LDAP_OTHER;
+			fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN<=%s)",
+				cf.f_av_value.bv_val );
 		}
 		fop.ors_attrsonly = 1;
 		fop.ors_attrs = slap_anlist_no_attrs;
@@ -689,8 +652,14 @@ again:
 		cb.sc_response = findcsn_cb;
 		break;
 	case FIND_PRESENT:
-		fop.ors_filter = op->ors_filter;
-		fop.ors_filterstr = op->ors_filterstr;
+		af.f_choice = LDAP_FILTER_AND;
+		af.f_next = NULL;
+		af.f_and = &cf;
+		cf.f_choice = LDAP_FILTER_LE;
+		cf.f_av_value = srs->sr_state.ctxcsn;
+		cf.f_next = op->ors_filter;
+		fop.ors_filter = &af;
+		filter2bv_x( &fop, fop.ors_filter, &fop.ors_filterstr );
 		fop.ors_attrsonly = 0;
 		fop.ors_attrs = uuid_anlist;
 		fop.ors_slimit = SLAP_NO_LIMIT;
@@ -712,20 +681,14 @@ again:
 		break;
 	}
 
-	fop.o_bd->bd_info = (BackendInfo *)on->on_info;
+	fop.o_bd->bd_info = on->on_info->oi_orig;
 	fop.o_bd->be_search( &fop, &frs );
 	fop.o_bd->bd_info = (BackendInfo *)on;
 
 	switch( mode ) {
 	case FIND_MAXCSN:
-		if ( ber_bvcmp( &si->si_ctxcsn[maxid], &maxcsn )) {
-#ifdef CHECK_CSN
-			Syntax *syn = slap_schema.si_ad_contextCSN->ad_type->sat_syntax;
-			assert( !syn->ssyn_validate( syn, &maxcsn ));
-#endif
-			ber_bvreplace( &si->si_ctxcsn[maxid], &maxcsn );
-			si->si_numops++;	/* ensure a checkpoint */
-		}
+		strcpy( si->si_ctxcsnbuf, maxcsn.bv_val );
+		si->si_ctxcsn.bv_len = maxcsn.bv_len;
 		break;
 	case FIND_CSN:
 		/* If matching CSN was not found, invalidate the context. */
@@ -740,42 +703,13 @@ again:
 		break;
 	case FIND_PRESENT:
 		op->o_tmpfree( pcookie.uuids, op->o_tmpmemctx );
+		op->o_tmpfree( fop.ors_filterstr.bv_val, op->o_tmpmemctx );
 		break;
 	}
 
 	return rc;
 }
 
-/* Should find a place to cache these */
-static mutexint *get_mutexint()
-{
-	mutexint *mi = ch_malloc( sizeof( mutexint ));
-	ldap_pvt_thread_mutex_init( &mi->mi_mutex );
-	mi->mi_int = 1;
-	return mi;
-}
-
-static void inc_mutexint( mutexint *mi )
-{
-	ldap_pvt_thread_mutex_lock( &mi->mi_mutex );
-	mi->mi_int++;
-	ldap_pvt_thread_mutex_unlock( &mi->mi_mutex );
-}
-
-/* return resulting counter */
-static int dec_mutexint( mutexint *mi )
-{
-	int i;
-	ldap_pvt_thread_mutex_lock( &mi->mi_mutex );
-	i = --mi->mi_int;
-	ldap_pvt_thread_mutex_unlock( &mi->mi_mutex );
-	if ( !i ) {
-		ldap_pvt_thread_mutex_destroy( &mi->mi_mutex );
-		ch_free( mi );
-	}
-	return i;
-}
-
 static void
 syncprov_free_syncop( syncops *so )
 {
@@ -799,12 +733,6 @@ syncprov_free_syncop( syncops *so )
 	ch_free( so->s_base.bv_val );
 	for ( sr=so->s_res; sr; sr=srnext ) {
 		srnext = sr->s_next;
-		if ( sr->s_e ) {
-			if ( !dec_mutexint( sr->s_e->e_private )) {
-				sr->s_e->e_private = NULL;
-				entry_free( sr->s_e );
-			}
-		}
 		ch_free( sr );
 	}
 	ldap_pvt_thread_mutex_destroy( &so->s_mutex );
@@ -813,13 +741,14 @@ syncprov_free_syncop( syncops *so )
 
 /* Send a persistent search response */
 static int
-syncprov_sendresp( Operation *op, opcookie *opc, syncops *so, int mode )
+syncprov_sendresp( Operation *op, opcookie *opc, syncops *so,
+	Entry **e, int mode )
 {
 	slap_overinst *on = opc->son;
 
 	SlapReply rs = { REP_SEARCH };
 	LDAPControl *ctrls[2];
-	struct berval cookie = BER_BVNULL, csns[2];
+	struct berval cookie;
 	Entry e_uuid = {0};
 	Attribute a_uuid = {0};
 
@@ -827,56 +756,46 @@ syncprov_sendresp( Operation *op, opcook
 		return SLAPD_ABANDON;
 
 	ctrls[1] = NULL;
-	if ( !BER_BVISNULL( &opc->sctxcsn )) {
-		csns[0] = opc->sctxcsn;
-		BER_BVZERO( &csns[1] );
-		slap_compose_sync_cookie( op, &cookie, csns, so->s_rid, slap_serverID ? slap_serverID : -1 );
-	}
-
-#ifdef LDAP_DEBUG
-	if ( so->s_sid > 0 ) {
-		Debug( LDAP_DEBUG_SYNC, "syncprov_sendresp: to=%03x, cookie=%s\n",
-			so->s_sid, cookie.bv_val ? cookie.bv_val : "", 0 );
-	} else {
-		Debug( LDAP_DEBUG_SYNC, "syncprov_sendresp: cookie=%s\n",
-			cookie.bv_val ? cookie.bv_val : "", 0, 0 );
-	}
-#endif
+	slap_compose_sync_cookie( op, &cookie, &opc->sctxcsn, so->s_rid );
 
 	e_uuid.e_attrs = &a_uuid;
 	a_uuid.a_desc = slap_schema.si_ad_entryUUID;
 	a_uuid.a_nvals = &opc->suuid;
 	rs.sr_err = syncprov_state_ctrl( op, &rs, &e_uuid,
 		mode, ctrls, 0, 1, &cookie );
-	if ( !BER_BVISNULL( &cookie )) {
-		op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
-	}
+	op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
 
 	rs.sr_ctrls = ctrls;
-	rs.sr_entry = &e_uuid;
-	if ( mode == LDAP_SYNC_ADD || mode == LDAP_SYNC_MODIFY ) {
-		e_uuid = *opc->se;
-		e_uuid.e_private = NULL;
-	}
-
+	op->o_bd->bd_info = (BackendInfo *)on->on_info;
 	switch( mode ) {
 	case LDAP_SYNC_ADD:
-		if ( opc->sreference && so->s_op->o_managedsait <= SLAP_CONTROL_IGNORED ) {
+		rs.sr_entry = *e;
+		if ( rs.sr_entry->e_private )
+			rs.sr_flags = REP_ENTRY_MUSTRELEASE;
+		if ( opc->sreference ) {
 			rs.sr_ref = get_entry_referrals( op, rs.sr_entry );
 			rs.sr_err = send_search_reference( op, &rs );
 			ber_bvarray_free( rs.sr_ref );
+			if ( !rs.sr_entry )
+				*e = NULL;
 			break;
 		}
 		/* fallthru */
 	case LDAP_SYNC_MODIFY:
+		rs.sr_entry = *e;
+		if ( rs.sr_entry->e_private )
+			rs.sr_flags = REP_ENTRY_MUSTRELEASE;
 		rs.sr_attrs = op->ors_attrs;
 		rs.sr_err = send_search_entry( op, &rs );
+		if ( !rs.sr_entry )
+			*e = NULL;
 		break;
 	case LDAP_SYNC_DELETE:
 		e_uuid.e_attrs = NULL;
 		e_uuid.e_name = opc->sdn;
 		e_uuid.e_nname = opc->sndn;
-		if ( opc->sreference && so->s_op->o_managedsait <= SLAP_CONTROL_IGNORED ) {
+		rs.sr_entry = &e_uuid;
+		if ( opc->sreference ) {
 			struct berval bv = BER_BVNULL;
 			rs.sr_ref = &bv;
 			rs.sr_err = send_search_reference( op, &rs );
@@ -889,111 +808,87 @@ syncprov_sendresp( Operation *op, opcook
 	}
 	/* In case someone else freed it already? */
 	if ( rs.sr_ctrls ) {
-		int i;
-		for ( i=0; rs.sr_ctrls[i]; i++ ) {
-			if ( rs.sr_ctrls[i] == ctrls[0] ) {
-				op->o_tmpfree( ctrls[0]->ldctl_value.bv_val, op->o_tmpmemctx );
-				ctrls[0]->ldctl_value.bv_val = NULL;
-				break;
-			}
-		}
+		op->o_tmpfree( rs.sr_ctrls[0], op->o_tmpmemctx );
 		rs.sr_ctrls = NULL;
 	}
 
 	return rs.sr_err;
 }
 
-static void
-syncprov_qstart( syncops *so );
-
 /* Play back queued responses */
 static int
-syncprov_qplay( Operation *op, syncops *so )
+syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
 {
-	slap_overinst *on = LDAP_SLIST_FIRST(&so->s_op->o_extra)->oe_key;
 	syncres *sr;
 	Entry *e;
 	opcookie opc;
 	int rc = 0;
 
 	opc.son = on;
+	op->o_bd->bd_info = (BackendInfo *)on->on_info;
 
-	do {
+	for (;;) {
 		ldap_pvt_thread_mutex_lock( &so->s_mutex );
 		sr = so->s_res;
 		if ( sr )
 			so->s_res = sr->s_next;
 		if ( !so->s_res )
 			so->s_restail = NULL;
-		/* Exit loop with mutex held */
-		if ( !sr || so->s_op->o_abandon )
-			break;
 		ldap_pvt_thread_mutex_unlock( &so->s_mutex );
 
-		if ( sr->s_mode == LDAP_SYNC_NEW_COOKIE ) {
-			SlapReply rs = { REP_INTERMEDIATE };
-
-			rc = syncprov_sendinfo( op, &rs, LDAP_TAG_SYNC_NEW_COOKIE,
-				&sr->s_csn, 0, NULL, 0 );
-		} else {
-			opc.sdn = sr->s_dn;
-			opc.sndn = sr->s_ndn;
-			opc.suuid = sr->s_uuid;
-			opc.sctxcsn = sr->s_csn;
-			opc.sreference = sr->s_isreference;
-			opc.se = sr->s_e;
-
-			rc = syncprov_sendresp( op, &opc, so, sr->s_mode );
+		if ( !sr || so->s_op->o_abandon )
+			break;
 
-		}
-		if ( sr->s_e ) {
-			if ( !dec_mutexint( sr->s_e->e_private )) {
-				sr->s_e->e_private = NULL;
-				entry_free ( sr->s_e );
+		opc.sdn = sr->s_dn;
+		opc.sndn = sr->s_ndn;
+		opc.suuid = sr->s_uuid;
+		opc.sctxcsn = sr->s_csn;
+		opc.sreference = sr->s_isreference;
+		e = NULL;
+
+		if ( sr->s_mode != LDAP_SYNC_DELETE ) {
+			rc = be_entry_get_rw( op, &opc.sndn, NULL, NULL, 0, &e );
+			if ( rc ) {
+				ch_free( sr );
+				continue;
 			}
 		}
+		rc = syncprov_sendresp( op, &opc, so, &e, sr->s_mode );
 
-		ch_free( sr );
-
-		/* Exit loop with mutex held */
-		ldap_pvt_thread_mutex_lock( &so->s_mutex );
-
-	} while (0);
+		if ( e ) {
+			be_entry_release_rw( op, e, 0 );
+		}
 
-	/* We now only send one change at a time, to prevent one
-	 * psearch from hogging all the CPU. Resubmit this task if
-	 * there are more responses queued and no errors occurred.
-	 */
+		ch_free( sr );
 
-	if ( rc == 0 && so->s_res ) {
-		syncprov_qstart( so );
-	} else {
-		so->s_flags ^= PS_TASK_QUEUED;
+		if ( rc )
+			break;
 	}
-
-	ldap_pvt_thread_mutex_unlock( &so->s_mutex );
+	op->o_bd->bd_info = (BackendInfo *)on;
 	return rc;
 }
 
-/* task for playing back queued responses */
+/* runqueue task for playing back queued responses */
 static void *
 syncprov_qtask( void *ctx, void *arg )
 {
-	syncops *so = arg;
+	struct re_s *rtask = arg;
+	syncops *so = rtask->arg;
+	slap_overinst *on = so->s_op->o_private;
 	OperationBuffer opbuf;
 	Operation *op;
 	BackendDB be;
 	int rc;
 
-	op = &opbuf.ob_op;
+	op = (Operation *) &opbuf;
 	*op = *so->s_op;
-	op->o_hdr = &opbuf.ob_hdr;
-	op->o_controls = opbuf.ob_controls;
-	memset( op->o_controls, 0, sizeof(opbuf.ob_controls) );
+	op->o_hdr = (Opheader *)(op+1);
+	op->o_controls = (void **)(op->o_hdr+1);
+	memset( op->o_controls, 0, SLAP_MAX_CIDS * sizeof(void *));
 
 	*op->o_hdr = *so->s_op->o_hdr;
 
-	op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx, 1);
+	op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx);
 	op->o_tmpmfuncs = &slap_sl_mfuncs;
 	op->o_threadctx = ctx;
 
@@ -1001,14 +896,36 @@ syncprov_qtask( void *ctx, void *arg )
 	be = *so->s_op->o_bd;
 	be.be_flags |= SLAP_DBFLAG_OVERLAY;
 	op->o_bd = &be;
-	LDAP_SLIST_FIRST(&op->o_extra) = NULL;
+	op->o_private = NULL;
 	op->o_callback = NULL;
 
-	rc = syncprov_qplay( op, so );
+	rc = syncprov_qplay( op, on, so );
 
 	/* decrement use count... */
 	syncprov_free_syncop( so );
 
+	/* wait until we get explicitly scheduled again */
+	ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+	ldap_pvt_runqueue_stoptask( &slapd_rq, rtask );
+	if ( rc == 0 ) {
+		ldap_pvt_runqueue_resched( &slapd_rq, rtask, 1 );
+	} else {
+		/* bail out on any error */
+		ldap_pvt_runqueue_remove( &slapd_rq, rtask );
+	}
+	ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+
+#if 0	/* FIXME: connection_close isn't exported from slapd.
+		 * should it be?
+		 */
+	if ( rc ) {
+		ldap_pvt_thread_mutex_lock( &op->o_conn->c_mutex );
+		if ( connection_state_closing( op->o_conn )) {
+			connection_close( op->o_conn );
+		}
+		ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );
+	}
+#endif
 	return NULL;
 }
 
@@ -1016,10 +933,27 @@ syncprov_qtask( void *ctx, void *arg )
 static void
 syncprov_qstart( syncops *so )
 {
-	so->s_flags |= PS_TASK_QUEUED;
-	so->s_inuse++;
-	ldap_pvt_thread_pool_submit( &connection_pool, 
-		syncprov_qtask, so );
+	int wake=0;
+	ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+	if ( !so->s_qtask ) {
+		so->s_qtask = ldap_pvt_runqueue_insert( &slapd_rq, RUNQ_INTERVAL,
+			syncprov_qtask, so, "syncprov_qtask",
+			so->s_op->o_conn->c_peer_name.bv_val );
+		++so->s_inuse;
+		wake = 1;
+	} else {
+		if (!ldap_pvt_runqueue_isrunning( &slapd_rq, so->s_qtask ) &&
+			!so->s_qtask->next_sched.tv_sec ) {
+			so->s_qtask->interval.tv_sec = 0;
+			ldap_pvt_runqueue_resched( &slapd_rq, so->s_qtask, 0 );
+			so->s_qtask->interval.tv_sec = RUNQ_INTERVAL;
+			++so->s_inuse;
+			wake = 1;
+		}
+	}
+	ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+	if ( wake )
+		slap_wake_listener();
 }
 
 /* Queue a persistent search response */
@@ -1027,26 +961,10 @@ static int
 syncprov_qresp( opcookie *opc, syncops *so, int mode )
 {
 	syncres *sr;
-	int srsize;
-	struct berval cookie = opc->sctxcsn;
-
-	if ( mode == LDAP_SYNC_NEW_COOKIE ) {
-		syncprov_info_t	*si = opc->son->on_bi.bi_private;
-
-		slap_compose_sync_cookie( NULL, &cookie, si->si_ctxcsn,
-			so->s_rid, slap_serverID ? slap_serverID : -1);
-	}
 
-	srsize = sizeof(syncres) + opc->suuid.bv_len + 1 +
-		opc->sdn.bv_len + 1 + opc->sndn.bv_len + 1;
-	if ( cookie.bv_len )
-		srsize += cookie.bv_len + 1;
-	sr = ch_malloc( srsize );
+	sr = ch_malloc(sizeof(syncres) + opc->suuid.bv_len + 1 +
+		opc->sdn.bv_len + 1 + opc->sndn.bv_len + 1 + opc->sctxcsn.bv_len + 1 );
 	sr->s_next = NULL;
-	sr->s_e = opc->se;
-	/* bump refcount on this entry */
-	if ( opc->se )
-		inc_mutexint( opc->se->e_private );
 	sr->s_dn.bv_val = (char *)(sr + 1);
 	sr->s_dn.bv_len = opc->sdn.bv_len;
 	sr->s_mode = mode;
@@ -1058,17 +976,9 @@ syncprov_qresp( opcookie *opc, syncops *
 		 opc->sndn.bv_val ) + 1;
 	sr->s_uuid.bv_len = opc->suuid.bv_len;
 	AC_MEMCPY( sr->s_uuid.bv_val, opc->suuid.bv_val, opc->suuid.bv_len );
-	if ( cookie.bv_len ) {
-		sr->s_csn.bv_val = sr->s_uuid.bv_val + sr->s_uuid.bv_len + 1;
-		strcpy( sr->s_csn.bv_val, cookie.bv_val );
-	} else {
-		sr->s_csn.bv_val = NULL;
-	}
-	sr->s_csn.bv_len = cookie.bv_len;
-
-	if ( mode == LDAP_SYNC_NEW_COOKIE && cookie.bv_val ) {
-		ch_free( cookie.bv_val );
-	}
+	sr->s_csn.bv_val = sr->s_uuid.bv_val + sr->s_uuid.bv_len + 1;
+	sr->s_csn.bv_len = opc->sctxcsn.bv_len;
+	strcpy( sr->s_csn.bv_val, opc->sctxcsn.bv_val );
 
 	ldap_pvt_thread_mutex_lock( &so->s_mutex );
 	if ( !so->s_res ) {
@@ -1083,7 +993,7 @@ syncprov_qresp( opcookie *opc, syncops *
 		so->s_flags ^= PS_WROTE_BASE;
 		so->s_flags |= PS_FIND_BASE;
 	}
-	if (( so->s_flags & (PS_IS_DETACHED|PS_TASK_QUEUED)) == PS_IS_DETACHED ) {
+	if ( so->s_flags & PS_IS_DETACHED ) {
 		syncprov_qstart( so );
 	}
 	ldap_pvt_thread_mutex_unlock( &so->s_mutex );
@@ -1098,7 +1008,7 @@ syncprov_drop_psearch( syncops *so, int
 			ldap_pvt_thread_mutex_lock( &so->s_op->o_conn->c_mutex );
 		so->s_op->o_conn->c_n_ops_executing--;
 		so->s_op->o_conn->c_n_ops_completed++;
-		LDAP_STAILQ_REMOVE( &so->s_op->o_conn->c_ops, so->s_op, Operation,
+		LDAP_STAILQ_REMOVE( &so->s_op->o_conn->c_ops, so->s_op, slap_op,
 			o_next );
 		if ( lock )
 			ldap_pvt_thread_mutex_unlock( &so->s_op->o_conn->c_mutex );
@@ -1165,7 +1075,7 @@ syncprov_matchops( Operation *op, opcook
 
 	fbase_cookie fc;
 	syncops *ss, *sprev, *snext;
-	Entry *e = NULL;
+	Entry *e;
 	Attribute *a;
 	int rc;
 	struct berval newdn;
@@ -1187,29 +1097,21 @@ syncprov_matchops( Operation *op, opcook
 			db = *op->o_bd;
 			op->o_bd = &db;
 		}
-		rc = overlay_entry_get_ov( op, fc.fdn, NULL, NULL, 0, &e, on );
+		op->o_bd->bd_info = (BackendInfo *)on->on_info;
+		rc = be_entry_get_rw( op, fc.fdn, NULL, NULL, 0, &e );
 		/* If we're sending responses now, make a copy and unlock the DB */
 		if ( e && !saveit ) {
-			if ( !opc->se ) {
-				opc->se = entry_dup( e );
-				opc->se->e_private = get_mutexint();
-			}
-			overlay_entry_release_ov( op, e, 0, on );
-			e = opc->se;
+			Entry *e2 = entry_dup( e );
+			be_entry_release_rw( op, e, 0 );
+			e = e2;
 		}
+		op->o_bd->bd_info = (BackendInfo *)on;
 		if ( rc ) {
 			op->o_bd = b0;
 			return;
 		}
 	} else {
 		e = op->ora_e;
-		if ( !saveit ) {
-			if ( !opc->se ) {
-				opc->se = entry_dup( e );
-				opc->se->e_private = get_mutexint();
-			}
-			e = opc->se;
-		}
 	}
 
 	if ( saveit || op->o_tag == LDAP_REQ_ADD ) {
@@ -1230,29 +1132,10 @@ syncprov_matchops( Operation *op, opcook
 	for (ss = si->si_ops, sprev = (syncops *)&si->si_ops; ss;
 		sprev = ss, ss=snext)
 	{
-		Operation op2;
-		Opheader oh;
 		syncmatches *sm;
 		int found = 0;
 
 		snext = ss->s_next;
-		if ( ss->s_op->o_abandon )
-			continue;
-
-		/* Don't send ops back to the originator */
-		if ( opc->osid > 0 && opc->osid == ss->s_sid ) {
-			Debug( LDAP_DEBUG_SYNC, "syncprov_matchops: skipping original sid %03x\n",
-				opc->osid, 0, 0 );
-			continue;
-		}
-
-		/* Don't send ops back to the messenger */
-		if ( opc->rsid > 0 && opc->rsid == ss->s_sid ) {
-			Debug( LDAP_DEBUG_SYNC, "syncprov_matchops: skipping relayed sid %03x\n",
-				opc->rsid, 0, 0 );
-			continue;
-		}
-
 		/* validate base */
 		fc.fss = ss;
 		fc.fbase = 0;
@@ -1270,6 +1153,7 @@ syncprov_matchops( Operation *op, opcook
 			continue;
 		}
 
+
 		/* If we're sending results now, look for this op in old matches */
 		if ( !saveit ) {
 			syncmatches *old;
@@ -1292,23 +1176,9 @@ syncprov_matchops( Operation *op, opcook
 			}
 		}
 
-		if ( fc.fscope ) {
-			op2 = *ss->s_op;
-			oh = *op->o_hdr;
-			oh.oh_conn = ss->s_op->o_conn;
-			oh.oh_connid = ss->s_op->o_connid;
-			op2.o_bd = op->o_bd->bd_self;
-			op2.o_hdr = &oh;
-			op2.o_extra = op->o_extra;
-			op2.o_callback = NULL;
-			rc = test_filter( &op2, e, ss->s_op->ors_filter );
-		}
-
-		Debug( LDAP_DEBUG_TRACE, "syncprov_matchops: sid %03x fscope %d rc %d\n",
-			ss->s_sid, fc.fscope, rc );
-
 		/* check if current o_req_dn is in scope and matches filter */
-		if ( fc.fscope && rc == LDAP_COMPARE_TRUE ) {
+		if ( fc.fscope && test_filter( op, e, ss->s_op->ors_filter ) ==
+			LDAP_COMPARE_TRUE ) {
 			if ( saveit ) {
 				sm = op->o_tmpalloc( sizeof(syncmatches), op->o_tmpmemctx );
 				sm->sm_next = opc->smatches;
@@ -1325,32 +1195,14 @@ syncprov_matchops( Operation *op, opcook
 		} else if ( !saveit && found ) {
 			/* send DELETE */
 			syncprov_qresp( opc, ss, LDAP_SYNC_DELETE );
-		} else if ( !saveit ) {
-			syncprov_qresp( opc, ss, LDAP_SYNC_NEW_COOKIE );
-		}
-		if ( !saveit && found ) {
-			/* Decrement s_inuse, was incremented when called
-			 * with saveit == TRUE
-			 */
-			syncprov_free_syncop( ss );
 		}
 	}
 	ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
 
 	if ( op->o_tag != LDAP_REQ_ADD && e ) {
-		if ( !SLAP_ISOVERLAY( op->o_bd )) {
-			op->o_bd = &db;
-		}
-		if ( saveit )
-			overlay_entry_release_ov( op, e, 0, on );
-		op->o_bd = b0;
-	}
-	if ( opc->se && !saveit ) {
-		if ( !dec_mutexint( opc->se->e_private )) {
-			opc->se->e_private = NULL;
-			entry_free( opc->se );
-			opc->se = NULL;
-		}
+		op->o_bd->bd_info = (BackendInfo *)on->on_info;
+		be_entry_release_rw( op, e, 0 );
+		op->o_bd->bd_info = (BackendInfo *)on;
 	}
 	if ( freefdn ) {
 		op->o_tmpfree( fc.fdn->bv_val, op->o_tmpmemctx );
@@ -1375,23 +1227,26 @@ syncprov_op_cleanup( Operation *op, Slap
 	}
 
 	/* Remove op from lock table */
-	mt = opc->smt;
+	mtdummy.mt_op = op;
+	ldap_pvt_thread_mutex_lock( &si->si_mods_mutex );
+	mt = avl_find( si->si_mods, &mtdummy, sp_avl_cmp );
 	if ( mt ) {
-		ldap_pvt_thread_mutex_lock( &mt->mt_mutex );
-		mt->mt_mods = mt->mt_mods->mi_next;
+		modinst *mi = mt->mt_mods;
+
 		/* If there are more, promote the next one */
-		if ( mt->mt_mods ) {
+		ldap_pvt_thread_mutex_lock( &mt->mt_mutex );
+		if ( mi->mi_next ) {
+			mt->mt_mods = mi->mi_next;
 			mt->mt_op = mt->mt_mods->mi_op;
 			ldap_pvt_thread_mutex_unlock( &mt->mt_mutex );
 		} else {
-			ldap_pvt_thread_mutex_unlock( &mt->mt_mutex );
-			ldap_pvt_thread_mutex_lock( &si->si_mods_mutex );
 			avl_delete( &si->si_mods, mt, sp_avl_cmp );
-			ldap_pvt_thread_mutex_unlock( &si->si_mods_mutex );
+			ldap_pvt_thread_mutex_unlock( &mt->mt_mutex );
 			ldap_pvt_thread_mutex_destroy( &mt->mt_mutex );
 			ch_free( mt );
 		}
 	}
+	ldap_pvt_thread_mutex_unlock( &si->si_mods_mutex );
 	if ( !BER_BVISNULL( &opc->suuid ))
 		op->o_tmpfree( opc->suuid.bv_val, op->o_tmpmemctx );
 	if ( !BER_BVISNULL( &opc->sndn ))
@@ -1405,29 +1260,27 @@ syncprov_op_cleanup( Operation *op, Slap
 }
 
 static void
-syncprov_checkpoint( Operation *op, SlapReply *rs, slap_overinst *on )
+syncprov_checkpoint( Operation *op, SlapReply *rs, slap_overinst *on,
+	struct berval *csn )
 {
-	syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
 	Modifications mod;
 	Operation opm;
 	SlapReply rsm = { 0 };
+	struct berval bv[2];
 	slap_callback cb = {0};
-	BackendDB be;
-
-#ifdef CHECK_CSN
-	Syntax *syn = slap_schema.si_ad_contextCSN->ad_type->sat_syntax;
 
-	int i;
-	for ( i=0; i<si->si_numcsns; i++ ) {
-		assert( !syn->ssyn_validate( syn, si->si_ctxcsn+i ));
+	/* If ctxcsn is empty, delete it */
+	if ( BER_BVISEMPTY( csn )) {
+		mod.sml_values = NULL;
+	} else {
+		mod.sml_values = bv;
+		bv[1].bv_val = NULL;
+		bv[0] = *csn;
 	}
-#endif
-	mod.sml_numvals = si->si_numcsns;
-	mod.sml_values = si->si_ctxcsn;
 	mod.sml_nvalues = NULL;
 	mod.sml_desc = slap_schema.si_ad_contextCSN;
 	mod.sml_op = LDAP_MOD_REPLACE;
-	mod.sml_flags = SLAP_MOD_INTERNAL;
+	mod.sml_flags = 0;
 	mod.sml_next = NULL;
 
 	cb.sc_response = slap_null_cb;
@@ -1435,39 +1288,16 @@ syncprov_checkpoint( Operation *op, Slap
 	opm.o_tag = LDAP_REQ_MODIFY;
 	opm.o_callback = &cb;
 	opm.orm_modlist = &mod;
-	opm.orm_no_opattrs = 1;
-	if ( SLAP_GLUE_SUBORDINATE( op->o_bd )) {
-		be = *on->on_info->oi_origdb;
-		opm.o_bd = &be;
-	}
-	opm.o_req_dn = si->si_contextdn;
-	opm.o_req_ndn = si->si_contextdn;
+	opm.o_req_dn = op->o_bd->be_suffix[0];
+	opm.o_req_ndn = op->o_bd->be_nsuffix[0];
 	opm.o_bd->bd_info = on->on_info->oi_orig;
 	opm.o_managedsait = SLAP_CONTROL_NONCRITICAL;
-	opm.o_no_schema_check = 1;
+	SLAP_DBFLAGS( opm.o_bd ) |= SLAP_DBFLAG_NOLASTMOD;
 	opm.o_bd->be_modify( &opm, &rsm );
-
-	if ( rsm.sr_err == LDAP_NO_SUCH_OBJECT &&
-		SLAP_SYNC_SUBENTRY( opm.o_bd )) {
-		const char	*text;
-		char txtbuf[SLAP_TEXT_BUFLEN];
-		size_t textlen = sizeof txtbuf;
-		Entry *e = slap_create_context_csn_entry( opm.o_bd, NULL );
-		slap_mods2entry( &mod, &e, 0, 1, &text, txtbuf, textlen);
-		opm.ora_e = e;
-		opm.o_bd->be_add( &opm, &rsm );
-		if ( e == opm.ora_e )
-			be_entry_release_w( &opm, opm.ora_e );
-	}
-
+	SLAP_DBFLAGS( opm.o_bd ) ^= SLAP_DBFLAG_NOLASTMOD;
 	if ( mod.sml_next != NULL ) {
 		slap_mods_free( mod.sml_next, 1 );
 	}
-#ifdef CHECK_CSN
-	for ( i=0; i<si->si_numcsns; i++ ) {
-		assert( !syn->ssyn_validate( syn, si->si_ctxcsn+i ));
-	}
-#endif
 }
 
 static void
@@ -1495,7 +1325,6 @@ syncprov_add_slog( Operation *op )
 		AC_MEMCPY( se->se_csn.bv_val, op->o_csn.bv_val, op->o_csn.bv_len );
 		se->se_csn.bv_val[op->o_csn.bv_len] = '\0';
 		se->se_csn.bv_len = op->o_csn.bv_len;
-		se->se_sid = slap_parse_csn_sid( &se->se_csn );
 
 		ldap_pvt_thread_mutex_lock( &sl->sl_mutex );
 		if ( sl->sl_head ) {
@@ -1530,14 +1359,14 @@ playlog_cb( Operation *op, SlapReply *rs
 /* enter with sl->sl_mutex locked, release before returning */
 static void
 syncprov_playlog( Operation *op, SlapReply *rs, sessionlog *sl,
-	sync_control *srs, BerVarray ctxcsn, int numcsns, int *sids )
+	sync_control *srs, struct berval *ctxcsn )
 {
 	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
 	slog_entry *se;
 	int i, j, ndel, num, nmods, mmods;
-	char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
+	char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
 	BerVarray uuids;
-	struct berval delcsn[2];
+	struct berval delcsn;
 
 	if ( !sl->sl_num ) {
 		ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
@@ -1552,47 +1381,22 @@ syncprov_playlog( Operation *op, SlapRep
 		num * UUID_LEN, op->o_tmpmemctx );
 	uuids[0].bv_val = (char *)(uuids + num + 1);
 
-	delcsn[0].bv_len = 0;
-	delcsn[0].bv_val = cbuf;
-	BER_BVZERO(&delcsn[1]);
+	delcsn.bv_len = 0;
+	delcsn.bv_val = cbuf;
 
 	/* Make a copy of the relevant UUIDs. Put the Deletes up front
 	 * and everything else at the end. Do this first so we can
 	 * unlock the list mutex.
 	 */
-	Debug( LDAP_DEBUG_SYNC, "srs csn %s\n",
-		srs->sr_state.ctxcsn[0].bv_val, 0, 0 );
 	for ( se=sl->sl_head; se; se=se->se_next ) {
-		int k;
-		Debug( LDAP_DEBUG_SYNC, "log csn %s\n", se->se_csn.bv_val, 0, 0 );
-		ndel = 1;
-		for ( k=0; k<srs->sr_state.numcsns; k++ ) {
-			if ( se->se_sid == srs->sr_state.sids[k] ) {
-				ndel = ber_bvcmp( &se->se_csn, &srs->sr_state.ctxcsn[k] );
-				break;
-			}
-		}
-		if ( ndel <= 0 ) {
-			Debug( LDAP_DEBUG_SYNC, "cmp %d, too old\n", ndel, 0, 0 );
-			continue;
-		}
-		ndel = 0;
-		for ( k=0; k<numcsns; k++ ) {
-			if ( se->se_sid == sids[k] ) {
-				ndel = ber_bvcmp( &se->se_csn, &ctxcsn[k] );
-				break;
-			}
-		}
-		if ( ndel > 0 ) {
-			Debug( LDAP_DEBUG_SYNC, "cmp %d, too new\n", ndel, 0, 0 );
-			break;
-		}
+		if ( ber_bvcmp( &se->se_csn, &srs->sr_state.ctxcsn ) <= 0 ) continue;
+		if ( ber_bvcmp( &se->se_csn, ctxcsn ) > 0 ) break;
 		if ( se->se_tag == LDAP_REQ_DELETE ) {
 			j = i;
 			i++;
 			AC_MEMCPY( cbuf, se->se_csn.bv_val, se->se_csn.bv_len );
-			delcsn[0].bv_len = se->se_csn.bv_len;
-			delcsn[0].bv_val[delcsn[0].bv_len] = '\0';
+			delcsn.bv_len = se->se_csn.bv_len;
+			delcsn.bv_val[delcsn.bv_len] = '\0';
 		} else {
 			nmods++;
 			j = num - nmods;
@@ -1637,7 +1441,11 @@ syncprov_playlog( Operation *op, SlapRep
 		SlapReply frs = { REP_RESULT };
 		int rc;
 		Filter mf, af;
-		AttributeAssertion eq = ATTRIBUTEASSERTION_INIT;
+#ifdef LDAP_COMP_MATCH
+		AttributeAssertion eq = { NULL, BER_BVNULL, NULL };
+#else
+		AttributeAssertion eq;
+#endif
 		slap_callback cb = {0};
 
 		fop = *op;
@@ -1661,7 +1469,7 @@ syncprov_playlog( Operation *op, SlapRep
 		fop.ors_filter = &af;
 
 		cb.sc_response = playlog_cb;
-		fop.o_bd->bd_info = (BackendInfo *)on->on_info;
+		fop.o_bd->bd_info = on->on_info->oi_orig;
 
 		for ( i=ndel; i<num; i++ ) {
 			if ( uuids[i].bv_len == 0 ) continue;
@@ -1682,19 +1490,10 @@ syncprov_playlog( Operation *op, SlapRep
 	if ( ndel ) {
 		struct berval cookie;
 
-		if ( delcsn[0].bv_len ) {
-			slap_compose_sync_cookie( op, &cookie, delcsn, srs->sr_state.rid,
-				slap_serverID ? slap_serverID : -1 );
-
-			Debug( LDAP_DEBUG_SYNC, "syncprov_playlog: cookie=%s\n", cookie.bv_val, 0, 0 );
-		}
-
+		slap_compose_sync_cookie( op, &cookie, &delcsn, srs->sr_state.rid );
 		uuids[ndel].bv_val = NULL;
-		syncprov_sendinfo( op, rs, LDAP_TAG_SYNC_ID_SET,
-			delcsn[0].bv_len ? &cookie : NULL, 0, uuids, 1 );
-		if ( delcsn[0].bv_len ) {
-			op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
-		}
+		syncprov_sendinfo( op, rs, LDAP_TAG_SYNC_ID_SET, &cookie, 0, uuids, 1 );
+		op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
 	}
 	op->o_tmpfree( uuids, op->o_tmpmemctx );
 }
@@ -1709,153 +1508,52 @@ syncprov_op_response( Operation *op, Sla
 
 	if ( rs->sr_err == LDAP_SUCCESS )
 	{
-		struct berval maxcsn;
-		char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
-		int do_check = 0, have_psearches, foundit, csn_changed = 0;
-
-		ldap_pvt_thread_mutex_lock( &si->si_resp_mutex );
+		struct berval maxcsn = BER_BVNULL;
+		char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
+		int do_check = 0;
 
 		/* Update our context CSN */
 		cbuf[0] = '\0';
-		maxcsn.bv_val = cbuf;
-		maxcsn.bv_len = sizeof(cbuf);
-		ldap_pvt_thread_rdwr_wlock( &si->si_csn_rwlock );
-
-		slap_get_commit_csn( op, &maxcsn, &foundit );
-		if ( BER_BVISEMPTY( &maxcsn ) && SLAP_GLUE_SUBORDINATE( op->o_bd )) {
-			/* syncrepl queues the CSN values in the db where
-			 * it is configured , not where the changes are made.
-			 * So look for a value in the glue db if we didn't
-			 * find any in this db.
-			 */
-			BackendDB *be = op->o_bd;
-			op->o_bd = select_backend( &be->be_nsuffix[0], 1);
-			maxcsn.bv_val = cbuf;
-			maxcsn.bv_len = sizeof(cbuf);
-			slap_get_commit_csn( op, &maxcsn, &foundit );
-			op->o_bd = be;
-		}
-		if ( !BER_BVISEMPTY( &maxcsn ) ) {
-			int i, sid;
-#ifdef CHECK_CSN
-			Syntax *syn = slap_schema.si_ad_contextCSN->ad_type->sat_syntax;
-			assert( !syn->ssyn_validate( syn, &maxcsn ));
-#endif
-			sid = slap_parse_csn_sid( &maxcsn );
-			for ( i=0; i<si->si_numcsns; i++ ) {
-				if ( sid == si->si_sids[i] ) {
-					if ( ber_bvcmp( &maxcsn, &si->si_ctxcsn[i] ) > 0 ) {
-						ber_bvreplace( &si->si_ctxcsn[i], &maxcsn );
-						csn_changed = 1;
-					}
-					break;
-				}
-			}
-			/* It's a new SID for us */
-			if ( i == si->si_numcsns ) {
-				value_add_one( &si->si_ctxcsn, &maxcsn );
-				csn_changed = 1;
-				si->si_numcsns++;
-				si->si_sids = ch_realloc( si->si_sids, si->si_numcsns *
-					sizeof(int));
-				si->si_sids[i] = sid;
+		ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+		slap_get_commit_csn( op, &maxcsn );
+		if ( !BER_BVISNULL( &maxcsn ) ) {
+			strcpy( cbuf, maxcsn.bv_val );
+			if ( ber_bvcmp( &maxcsn, &si->si_ctxcsn ) > 0 ) {
+				strcpy( si->si_ctxcsnbuf, cbuf );
+				si->si_ctxcsn.bv_len = maxcsn.bv_len;
 			}
 		}
 
 		/* Don't do any processing for consumer contextCSN updates */
-		if ( op->o_dont_replicate ) {
-			if ( op->o_tag == LDAP_REQ_MODIFY &&
-				op->orm_modlist->sml_op == LDAP_MOD_REPLACE &&
-				op->orm_modlist->sml_desc == slap_schema.si_ad_contextCSN ) {
-			/* Catch contextCSN updates from syncrepl. We have to look at
-			 * all the attribute values, as there may be more than one csn
-			 * that changed, and only one can be passed in the csn queue.
-			 */
-			Modifications *mod = op->orm_modlist;
-			int i, j, sid;
-
-			for ( i=0; i<mod->sml_numvals; i++ ) {
-				sid = slap_parse_csn_sid( &mod->sml_values[i] );
-				for ( j=0; j<si->si_numcsns; j++ ) {
-					if ( sid == si->si_sids[j] ) {
-						if ( ber_bvcmp( &mod->sml_values[i], &si->si_ctxcsn[j] ) > 0 ) {
-							ber_bvreplace( &si->si_ctxcsn[j], &mod->sml_values[i] );
-							csn_changed = 1;
-						}
-						break;
-					}
-				}
-
-				if ( j == si->si_numcsns ) {
-					value_add_one( &si->si_ctxcsn, &mod->sml_values[i] );
-					si->si_numcsns++;
-					si->si_sids = ch_realloc( si->si_sids, si->si_numcsns *
-						sizeof(int));
-					si->si_sids[j] = sid;
-					csn_changed = 1;
-				}
-			}
-			ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
-
-			if ( csn_changed ) {
-				ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
-				have_psearches = ( si->si_ops != NULL );
-				ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
-
-				if ( have_psearches ) {
-					for ( sm = opc->smatches; sm; sm=sm->sm_next ) {
-						if ( sm->sm_op->s_op->o_abandon )
-							continue;
-						syncprov_qresp( opc, sm->sm_op, LDAP_SYNC_NEW_COOKIE );
-					}
-				}
-			}
-			} else {
-			ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
-			}
-			goto leave;
+		if ( SLAP_SYNC_SHADOW( op->o_bd ) && 
+			op->o_msgid == SLAP_SYNC_UPDATE_MSGID ) {
+			ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+			return SLAP_CB_CONTINUE;
 		}
 
 		si->si_numops++;
 		if ( si->si_chkops || si->si_chktime ) {
-			/* Never checkpoint adding the context entry,
-			 * it will deadlock
-			 */
-			if ( op->o_tag != LDAP_REQ_ADD ||
-				!dn_match( &op->o_req_ndn, &si->si_contextdn )) {
-				if ( si->si_chkops && si->si_numops >= si->si_chkops ) {
-					do_check = 1;
-					si->si_numops = 0;
-				}
-				if ( si->si_chktime &&
-					(op->o_time - si->si_chklast >= si->si_chktime )) {
-					if ( si->si_chklast ) {
-						do_check = 1;
-						si->si_chklast = op->o_time;
-					} else {
-						si->si_chklast = 1;
-					}
-				}
+			if ( si->si_chkops && si->si_numops >= si->si_chkops ) {
+				do_check = 1;
+				si->si_numops = 0;
+			}
+			if ( si->si_chktime &&
+				(op->o_time - si->si_chklast >= si->si_chktime )) {
+				do_check = 1;
+				si->si_chklast = op->o_time;
 			}
 		}
-		ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
+		ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
 
-		if ( do_check ) {
-			ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
-			syncprov_checkpoint( op, rs, on );
-			ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
-		}
+		opc->sctxcsn.bv_len = maxcsn.bv_len;
+		opc->sctxcsn.bv_val = cbuf;
 
-		/* only update consumer ctx if this is a newer csn */
-		if ( csn_changed ) {
-			opc->sctxcsn = maxcsn;
+		if ( do_check ) {
+			syncprov_checkpoint( op, rs, on, &opc->sctxcsn );
 		}
 
 		/* Handle any persistent searches */
-		ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
-		have_psearches = ( si->si_ops != NULL );
-		ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
-		if ( have_psearches ) {
+		if ( si->si_ops ) {
 			switch(op->o_tag) {
 			case LDAP_REQ_ADD:
 			case LDAP_REQ_MODIFY:
@@ -1880,7 +1578,7 @@ syncprov_op_response( Operation *op, Sla
 		if ( si->si_logs && op->o_tag != LDAP_REQ_ADD ) {
 			syncprov_add_slog( op );
 		}
-leave:		ldap_pvt_thread_mutex_unlock( &si->si_resp_mutex );
+
 	}
 	return SLAP_CB_CONTINUE;
 }
@@ -1896,23 +1594,24 @@ syncprov_op_compare( Operation *op, Slap
 	syncprov_info_t		*si = on->on_bi.bi_private;
 	int rc = SLAP_CB_CONTINUE;
 
-	if ( dn_match( &op->o_req_ndn, &si->si_contextdn ) &&
+	if ( dn_match( &op->o_req_ndn, op->o_bd->be_nsuffix ) &&
 		op->oq_compare.rs_ava->aa_desc == slap_schema.si_ad_contextCSN )
 	{
 		Entry e = {0};
 		Attribute a = {0};
+		struct berval bv[2];
 
-		e.e_name = si->si_contextdn;
-		e.e_nname = si->si_contextdn;
-		e.e_attrs = &a;
-
-		a.a_desc = slap_schema.si_ad_contextCSN;
+		e.e_name = op->o_bd->be_suffix[0];
+		e.e_nname = op->o_bd->be_nsuffix[0];
 
-		ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
+		BER_BVZERO( &bv[1] );
+		bv[0] = si->si_ctxcsn;
 
-		a.a_vals = si->si_ctxcsn;
+		a.a_desc = slap_schema.si_ad_contextCSN;
+		a.a_vals = bv;
 		a.a_nvals = a.a_vals;
-		a.a_numvals = si->si_numcsns;
+
+		ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
 
 		rs->sr_err = access_allowed( op, &e, op->oq_compare.rs_ava->aa_desc,
 			&op->oq_compare.rs_ava->aa_value, ACL_COMPARE, NULL );
@@ -1931,17 +1630,17 @@ syncprov_op_compare( Operation *op, Slap
 
 		rs->sr_err = LDAP_COMPARE_FALSE;
 
-		if ( attr_valfind( &a,
+		if ( value_find_ex( op->oq_compare.rs_ava->aa_desc,
 			SLAP_MR_ATTRIBUTE_VALUE_NORMALIZED_MATCH |
 				SLAP_MR_ASSERTED_VALUE_NORMALIZED_MATCH,
-				&op->oq_compare.rs_ava->aa_value, NULL, op->o_tmpmemctx ) == 0 )
+				a.a_nvals, &op->oq_compare.rs_ava->aa_value, op->o_tmpmemctx ) == 0 )
 		{
 			rs->sr_err = LDAP_COMPARE_TRUE;
 		}
 
 return_results:;
 
-		ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
+		ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
 
 		send_ldap_result( op, rs );
 
@@ -1959,19 +1658,12 @@ syncprov_op_mod( Operation *op, SlapRepl
 {
 	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
 	syncprov_info_t		*si = on->on_bi.bi_private;
-	slap_callback *cb;
-	opcookie *opc;
-	int have_psearches, cbsize;
-
-	ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
-	have_psearches = ( si->si_ops != NULL );
-	ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
-
-	cbsize = sizeof(slap_callback) + sizeof(opcookie) +
-		(have_psearches ? sizeof(modinst) : 0 );
 
-	cb = op->o_tmpcalloc(1, cbsize, op->o_tmpmemctx);
-	opc = (opcookie *)(cb+1);
+	slap_callback *cb = op->o_tmpcalloc(1, sizeof(slap_callback)+
+		sizeof(opcookie) +
+		(si->si_ops ? sizeof(modinst) : 0 ),
+		op->o_tmpmemctx);
+	opcookie *opc = (opcookie *)(cb+1);
 	opc->son = on;
 	cb->sc_response = syncprov_op_response;
 	cb->sc_cleanup = syncprov_op_cleanup;
@@ -1979,22 +1671,10 @@ syncprov_op_mod( Operation *op, SlapRepl
 	cb->sc_next = op->o_callback;
 	op->o_callback = cb;
 
-	opc->osid = -1;
-	opc->rsid = -1;
-	if ( op->o_csn.bv_val ) {
-		opc->osid = slap_parse_csn_sid( &op->o_csn );
-	}
-	if ( op->o_controls ) {
-		struct sync_cookie *scook =
-		op->o_controls[slap_cids.sc_LDAPsync];
-		if ( scook )
-			opc->rsid = scook->sid;
-	}
-
 	/* If there are active persistent searches, lock this operation.
 	 * See seqmod.c for the locking logic on its own.
 	 */
-	if ( have_psearches ) {
+	if ( si->si_ops ) {
 		modtarget *mt, mtdummy;
 		modinst *mi;
 
@@ -2007,31 +1687,13 @@ syncprov_op_mod( Operation *op, SlapRepl
 		mt = avl_find( si->si_mods, &mtdummy, sp_avl_cmp );
 		if ( mt ) {
 			ldap_pvt_thread_mutex_lock( &mt->mt_mutex );
-			if ( mt->mt_mods == NULL ) {
-				/* Cannot reuse this mt, as another thread is about
-				 * to release it in syncprov_op_cleanup.
-				 */
-				ldap_pvt_thread_mutex_unlock( &mt->mt_mutex );
-				mt = NULL;
-			}
-		}
-		if ( mt ) {
 			ldap_pvt_thread_mutex_unlock( &si->si_mods_mutex );
 			mt->mt_tail->mi_next = mi;
 			mt->mt_tail = mi;
 			/* wait for this op to get to head of list */
 			while ( mt->mt_mods != mi ) {
 				ldap_pvt_thread_mutex_unlock( &mt->mt_mutex );
-				/* FIXME: if dynamic config can delete overlays or
-				 * databases we'll have to check for cleanup here.
-				 * Currently it's not an issue because there are
-				 * no dynamic config deletes...
-				 */
-				if ( slapd_shutdown )
-					return SLAPD_ABANDON;
-
-				if ( !ldap_pvt_thread_pool_pausecheck( &connection_pool ))
-					ldap_pvt_thread_yield();
+				ldap_pvt_thread_yield();
 				ldap_pvt_thread_mutex_lock( &mt->mt_mutex );
 
 				/* clean up if the caller is giving up */
@@ -2057,10 +1719,9 @@ syncprov_op_mod( Operation *op, SlapRepl
 			avl_insert( &si->si_mods, mt, sp_avl_cmp, avl_dup_error );
 			ldap_pvt_thread_mutex_unlock( &si->si_mods_mutex );
 		}
-		opc->smt = mt;
 	}
 
-	if (( have_psearches || si->si_logs ) && op->o_tag != LDAP_REQ_ADD )
+	if (( si->si_ops || si->si_logs ) && op->o_tag != LDAP_REQ_ADD )
 		syncprov_matchops( op, opc, 1 );
 
 	return SLAP_CB_CONTINUE;
@@ -2078,12 +1739,9 @@ syncprov_op_extended( Operation *op, Sla
 typedef struct searchstate {
 	slap_overinst *ss_on;
 	syncops *ss_so;
-	BerVarray ss_ctxcsn;
-	int *ss_sids;
-	int ss_numcsns;
-#define	SS_PRESENT	0x01
-#define	SS_CHANGED	0x02
-	int ss_flags;
+	int ss_present;
+	struct berval ss_ctxcsn;
+	char ss_csnbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
 } searchstate;
 
 static int
@@ -2097,18 +1755,9 @@ syncprov_search_cleanup( Operation *op,
 	return 0;
 }
 
-typedef struct SyncOperationBuffer {
-	Operation		sob_op;
-	Opheader		sob_hdr;
-	OpExtra			sob_oe;
-	AttributeName	sob_extra;	/* not always present */
-	/* Further data allocated here */
-} SyncOperationBuffer;
-
 static void
 syncprov_detach_op( Operation *op, syncops *so, slap_overinst *on )
 {
-	SyncOperationBuffer *sopbuf2;
 	Operation *op2;
 	int i, alen = 0;
 	size_t size;
@@ -2120,16 +1769,14 @@ syncprov_detach_op( Operation *op, synco
 		alen += op->ors_attrs[i].an_name.bv_len + 1;
 	}
 	/* Make a new copy of the operation */
-	size = offsetof( SyncOperationBuffer, sob_extra ) +
+	size = sizeof(Operation) + sizeof(Opheader) +
 		(i ? ( (i+1) * sizeof(AttributeName) + alen) : 0) +
 		op->o_req_dn.bv_len + 1 +
 		op->o_req_ndn.bv_len + 1 +
 		op->o_ndn.bv_len + 1 +
 		so->s_filterstr.bv_len + 1;
-	sopbuf2 = ch_calloc( 1, size );
-	op2 = &sopbuf2->sob_op;
-	op2->o_hdr = &sopbuf2->sob_hdr;
-	LDAP_SLIST_FIRST(&op2->o_extra) = &sopbuf2->sob_oe;
+	op2 = (Operation *)ch_calloc( 1, size );
+	op2->o_hdr = (Opheader *)(op2+1);
 
 	/* Copy the fields we care about explicitly, leave the rest alone */
 	*op2->o_hdr = *op->o_hdr;
@@ -2137,22 +1784,20 @@ syncprov_detach_op( Operation *op, synco
 	op2->o_time = op->o_time;
 	op2->o_bd = on->on_info->oi_origdb;
 	op2->o_request = op->o_request;
-	op2->o_managedsait = op->o_managedsait;
-	LDAP_SLIST_FIRST(&op2->o_extra)->oe_key = on;
-	LDAP_SLIST_NEXT(LDAP_SLIST_FIRST(&op2->o_extra), oe_next) = NULL;
+	op2->o_private = on;
 
-	ptr = (char *) sopbuf2 + offsetof( SyncOperationBuffer, sob_extra );
 	if ( i ) {
-		op2->ors_attrs = (AttributeName *) ptr;
-		ptr = (char *) &op2->ors_attrs[i+1];
+		op2->ors_attrs = (AttributeName *)(op2->o_hdr + 1);
+		ptr = (char *)(op2->ors_attrs+i+1);
 		for (i=0; !BER_BVISNULL( &op->ors_attrs[i].an_name ); i++) {
 			op2->ors_attrs[i] = op->ors_attrs[i];
 			op2->ors_attrs[i].an_name.bv_val = ptr;
 			ptr = lutil_strcopy( ptr, op->ors_attrs[i].an_name.bv_val ) + 1;
 		}
 		BER_BVZERO( &op2->ors_attrs[i].an_name );
+	} else {
+		ptr = (char *)(op2->o_hdr + 1);
 	}
-
 	op2->o_authz = op->o_authz;
 	op2->o_ndn.bv_val = ptr;
 	ptr = lutil_strcopy(ptr, op->o_ndn.bv_val) + 1;
@@ -2190,10 +1835,12 @@ syncprov_detach_op( Operation *op, synco
 	op2->o_do_not_cache = 1;
 
 	/* Add op2 to conn so abandon will find us */
+	ldap_pvt_thread_mutex_lock( &op->o_conn->c_mutex );
 	op->o_conn->c_n_ops_executing++;
 	op->o_conn->c_n_ops_completed--;
 	LDAP_STAILQ_INSERT_TAIL( &op->o_conn->c_ops, op2, o_next );
 	so->s_flags |= PS_IS_DETACHED;
+	ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );
 
 	/* Prevent anyone else from trying to send a result for this op */
 	op->o_abandon = 1;
@@ -2204,7 +1851,6 @@ syncprov_search_response( Operation *op,
 {
 	searchstate *ss = op->o_callback->sc_private;
 	slap_overinst *on = ss->ss_on;
-	syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
 	sync_control *srs = op->o_controls[slap_cids.sc_LDAPsync];
 
 	if ( rs->sr_type == REP_SEARCH || rs->sr_type == REP_SEARCHREF ) {
@@ -2224,116 +1870,64 @@ syncprov_search_response( Operation *op,
 			a = attr_find( rs->sr_operational_attrs, slap_schema.si_ad_entryCSN );
 		}
 		if ( a ) {
-			int i, sid;
-			sid = slap_parse_csn_sid( &a->a_nvals[0] );
-
-			/* Don't send changed entries back to the originator */
-			if ( sid == srs->sr_state.sid && srs->sr_state.numcsns ) {
-				Debug( LDAP_DEBUG_SYNC,
-					"Entry %s changed by peer, ignored\n",
-					rs->sr_entry->e_name.bv_val, 0, 0 );
+			/* Make sure entry is less than the snapshot'd contextCSN */
+			if ( ber_bvcmp( &a->a_nvals[0], &ss->ss_ctxcsn ) > 0 ) {
+				Debug( LDAP_DEBUG_SYNC, "Entry %s CSN %s greater than snapshot %s\n",
+					rs->sr_entry->e_name.bv_val,
+					a->a_nvals[0].bv_val,
+					ss->ss_ctxcsn.bv_val );
 				return LDAP_SUCCESS;
 			}
 
-			/* If not a persistent search */
-			if ( !ss->ss_so ) {
-				/* Make sure entry is less than the snapshot'd contextCSN */
-				for ( i=0; i<ss->ss_numcsns; i++ ) {
-					if ( sid == ss->ss_sids[i] && ber_bvcmp( &a->a_nvals[0],
-						&ss->ss_ctxcsn[i] ) > 0 ) {
-						Debug( LDAP_DEBUG_SYNC,
-							"Entry %s CSN %s greater than snapshot %s\n",
-							rs->sr_entry->e_name.bv_val,
-							a->a_nvals[0].bv_val,
-							ss->ss_ctxcsn[i].bv_val );
-						return LDAP_SUCCESS;
-					}
-				}
-			}
-
-			/* Don't send old entries twice */
-			if ( srs->sr_state.ctxcsn ) {
-				for ( i=0; i<srs->sr_state.numcsns; i++ ) {
-					if ( sid == srs->sr_state.sids[i] &&
-						ber_bvcmp( &a->a_nvals[0],
-							&srs->sr_state.ctxcsn[i] )<= 0 ) {
-						Debug( LDAP_DEBUG_SYNC,
-							"Entry %s CSN %s older or equal to ctx %s\n",
-							rs->sr_entry->e_name.bv_val,
-							a->a_nvals[0].bv_val,
-							srs->sr_state.ctxcsn[i].bv_val );
-						return LDAP_SUCCESS;
-					}
-				}
+			/* Don't send the ctx entry twice */
+			if ( !BER_BVISNULL( &srs->sr_state.ctxcsn ) &&
+				bvmatch( &a->a_nvals[0], &srs->sr_state.ctxcsn ) ) {
+				Debug( LDAP_DEBUG_SYNC, "Entry %s CSN %s matches ctx %s\n",
+					rs->sr_entry->e_name.bv_val,
+					a->a_nvals[0].bv_val,
+					srs->sr_state.ctxcsn.bv_val );
+				return LDAP_SUCCESS;
 			}
 		}
 		rs->sr_ctrls = op->o_tmpalloc( sizeof(LDAPControl *)*2,
 			op->o_tmpmemctx );
 		rs->sr_ctrls[1] = NULL;
-		/* If we're in delta-sync mode, always send a cookie */
-		if ( si->si_nopres && si->si_usehint && a ) {
-			struct berval cookie;
-			slap_compose_sync_cookie( op, &cookie, a->a_nvals, srs->sr_state.rid, slap_serverID ? slap_serverID : -1 );
-			rs->sr_err = syncprov_state_ctrl( op, rs, rs->sr_entry,
-				LDAP_SYNC_ADD, rs->sr_ctrls, 0, 1, &cookie );
-		} else {
-			rs->sr_err = syncprov_state_ctrl( op, rs, rs->sr_entry,
-				LDAP_SYNC_ADD, rs->sr_ctrls, 0, 0, NULL );
-		}
+		rs->sr_err = syncprov_state_ctrl( op, rs, rs->sr_entry,
+			LDAP_SYNC_ADD, rs->sr_ctrls, 0, 0, NULL );
 	} else if ( rs->sr_type == REP_RESULT && rs->sr_err == LDAP_SUCCESS ) {
-		struct berval cookie = BER_BVNULL;
-
-		if ( ( ss->ss_flags & SS_CHANGED ) &&
-			ss->ss_ctxcsn && !BER_BVISNULL( &ss->ss_ctxcsn[0] )) {
-			slap_compose_sync_cookie( op, &cookie, ss->ss_ctxcsn,
-				srs->sr_state.rid, slap_serverID ? slap_serverID : -1 );
+		struct berval cookie;
 
-			Debug( LDAP_DEBUG_SYNC, "syncprov_search_response: cookie=%s\n", cookie.bv_val, 0, 0 );
-		}
+		slap_compose_sync_cookie( op, &cookie, &ss->ss_ctxcsn,
+			srs->sr_state.rid );
 
-		/* Is this a regular refresh?
-		 * Note: refresh never gets here if there were no changes
-		 */
+		/* Is this a regular refresh? */
 		if ( !ss->ss_so ) {
 			rs->sr_ctrls = op->o_tmpalloc( sizeof(LDAPControl *)*2,
 				op->o_tmpmemctx );
 			rs->sr_ctrls[1] = NULL;
 			rs->sr_err = syncprov_done_ctrl( op, rs, rs->sr_ctrls,
-				0, 1, &cookie, ( ss->ss_flags & SS_PRESENT ) ?  LDAP_SYNC_REFRESH_PRESENTS :
+				0, 1, &cookie, ss->ss_present ?  LDAP_SYNC_REFRESH_PRESENTS :
 					LDAP_SYNC_REFRESH_DELETES );
 			op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
 		} else {
 		/* It's RefreshAndPersist, transition to Persist phase */
-			syncprov_sendinfo( op, rs, ( ss->ss_flags & SS_PRESENT ) ?
+			syncprov_sendinfo( op, rs, ss->ss_present ?
 	 			LDAP_TAG_SYNC_REFRESH_PRESENT : LDAP_TAG_SYNC_REFRESH_DELETE,
-				( ss->ss_flags & SS_CHANGED ) ? &cookie : NULL,
-				1, NULL, 0 );
-			if ( !BER_BVISNULL( &cookie ))
-				op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
+				&cookie, 1, NULL, 0 );
+			op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
 
 			/* Detach this Op from frontend control */
-			ldap_pvt_thread_mutex_lock( &op->o_conn->c_mutex );
+			ldap_pvt_thread_mutex_lock( &ss->ss_so->s_mutex );
 
-			/* But not if this connection was closed along the way */
-			if ( op->o_abandon ) {
-				ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );
-				/* syncprov_ab_cleanup will free this syncop */
-				return SLAPD_ABANDON;
+			/* Turn off the refreshing flag */
+			ss->ss_so->s_flags ^= PS_IS_REFRESHING;
 
-			} else {
-				ldap_pvt_thread_mutex_lock( &ss->ss_so->s_mutex );
-				/* Turn off the refreshing flag */
-				ss->ss_so->s_flags ^= PS_IS_REFRESHING;
-
-				syncprov_detach_op( op, ss->ss_so, on );
-
-				ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );
-
-				/* If there are queued responses, fire them off */
-				if ( ss->ss_so->s_res )
-					syncprov_qstart( ss->ss_so );
-				ldap_pvt_thread_mutex_unlock( &ss->ss_so->s_mutex );
-			}
+			syncprov_detach_op( op, ss->ss_so, on );
+
+			/* If there are queued responses, fire them off */
+			if ( ss->ss_so->s_res )
+				syncprov_qstart( ss->ss_so );
+			ldap_pvt_thread_mutex_unlock( &ss->ss_so->s_mutex );
 
 			return LDAP_SUCCESS;
 		}
@@ -2348,13 +1942,12 @@ syncprov_op_search( Operation *op, SlapR
 	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
 	syncprov_info_t		*si = (syncprov_info_t *)on->on_bi.bi_private;
 	slap_callback	*cb;
-	int gotstate = 0, changed = 0, do_present = 0;
+	int gotstate = 0, nochange = 0, do_present;
 	syncops *sop = NULL;
 	searchstate *ss;
 	sync_control *srs;
-	BerVarray ctxcsn;
-	int i, *sids, numcsns;
-	struct berval mincsn;
+	struct berval ctxcsn;
+	char csnbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
 
 	if ( !(op->o_sync_mode & SLAP_SYNC_REFRESH) ) return SLAP_CB_CONTINUE;
 
@@ -2363,7 +1956,10 @@ syncprov_op_search( Operation *op, SlapR
 		return rs->sr_err;
 	}
 
+	do_present = si->si_nopres ? 0 : 1;
+
 	srs = op->o_controls[slap_cids.sc_LDAPsync];
+	op->o_managedsait = SLAP_CONTROL_NONCRITICAL;
 
 	/* If this is a persistent search, set it up right away */
 	if ( op->o_sync_mode & SLAP_SYNC_PERSIST ) {
@@ -2395,7 +1991,6 @@ syncprov_op_search( Operation *op, SlapR
 		*sop = so;
 		ldap_pvt_thread_mutex_init( &sop->s_mutex );
 		sop->s_rid = srs->sr_state.rid;
-		sop->s_sid = srs->sr_state.sid;
 		sop->s_inuse = 1;
 
 		ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
@@ -2405,115 +2000,35 @@ syncprov_op_search( Operation *op, SlapR
 	}
 
 	/* snapshot the ctxcsn */
-	ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
-	numcsns = si->si_numcsns;
-	if ( numcsns ) {
-		ber_bvarray_dup_x( &ctxcsn, si->si_ctxcsn, op->o_tmpmemctx );
-		sids = op->o_tmpalloc( numcsns * sizeof(int), op->o_tmpmemctx );
-		for ( i=0; i<numcsns; i++ )
-			sids[i] = si->si_sids[i];
-	} else {
-		ctxcsn = NULL;
-		sids = NULL;
-	}
-	ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
+	ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+	strcpy( csnbuf, si->si_ctxcsnbuf );
+	ctxcsn.bv_len = si->si_ctxcsn.bv_len;
+	ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+	ctxcsn.bv_val = csnbuf;
 	
 	/* If we have a cookie, handle the PRESENT lookups */
-	if ( srs->sr_state.ctxcsn ) {
+	if ( !BER_BVISNULL( &srs->sr_state.ctxcsn )) {
 		sessionlog *sl;
-		int i, j;
 
-		/* If we don't have any CSN of our own yet, pretend nothing
-		 * has changed.
-		 */
-		if ( !numcsns )
-			goto no_change;
+		/* The cookie was validated when it was parsed, just use it */
 
-		if ( !si->si_nopres )
-			do_present = SS_PRESENT;
-
-		/* If there are SIDs we don't recognize in the cookie, drop them */
-		for (i=0; i<srs->sr_state.numcsns; ) {
-			for (j=0; j<numcsns; j++) {
-				if ( srs->sr_state.sids[i] == sids[j] ) {
-					break;
-				}
+		/* If just Refreshing and nothing has changed, shortcut it */
+		if ( bvmatch( &srs->sr_state.ctxcsn, &ctxcsn )) {
+			nochange = 1;
+			if ( !(op->o_sync_mode & SLAP_SYNC_PERSIST) ) {
+				LDAPControl	*ctrls[2];
+
+				ctrls[0] = NULL;
+				ctrls[1] = NULL;
+				syncprov_done_ctrl( op, rs, ctrls, 0, 0,
+					NULL, LDAP_SYNC_REFRESH_DELETES );
+				rs->sr_ctrls = ctrls;
+				rs->sr_err = LDAP_SUCCESS;
+				send_ldap_result( op, rs );
+				rs->sr_ctrls = NULL;
+				return rs->sr_err;
 			}
-			/* not found */
-			if ( j == numcsns ) {
-				struct berval tmp = srs->sr_state.ctxcsn[i];
-				j = srs->sr_state.numcsns - 1;
-				srs->sr_state.ctxcsn[i] = srs->sr_state.ctxcsn[j];
-				tmp.bv_len = 0;
-				srs->sr_state.ctxcsn[j] = tmp;
-				srs->sr_state.numcsns = j;
-				srs->sr_state.sids[i] = srs->sr_state.sids[j];
-				continue;
-			}
-			i++;
-		}
-
-		/* Find the smallest CSN */
-		mincsn = srs->sr_state.ctxcsn[0];
-		for ( i=1; i<srs->sr_state.numcsns; i++ ) {
-			if ( ber_bvcmp( &mincsn, &srs->sr_state.ctxcsn[i] ) > 0 )
-				mincsn = srs->sr_state.ctxcsn[i];
-		}
-
-		/* If nothing has changed, shortcut it */
-		if ( srs->sr_state.numcsns == numcsns ) {
-			int i, j, newer;
-			for ( i=0; i<srs->sr_state.numcsns; i++ ) {
-				for ( j=0; j<numcsns; j++ ) {
-					if ( srs->sr_state.sids[i] != sids[j] )
-						continue;
-					newer = ber_bvcmp( &srs->sr_state.ctxcsn[i], &ctxcsn[j] );
-					/* If our state is newer, tell consumer about changes */
-					if ( newer < 0 )
-						changed = SS_CHANGED;
-					else if ( newer > 0 ) {
-					/* our state is older, tell consumer nothing */
-						rs->sr_err = LDAP_SUCCESS;
-bailout:
-						if ( sop ) {
-							syncops **sp = &si->si_ops;
-							
-							ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
-							while ( *sp != sop )
-								sp = &(*sp)->s_next;
-							*sp = sop->s_next;
-							ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
-							ch_free( sop );
-						}
-						rs->sr_ctrls = NULL;
-						send_ldap_result( op, rs );
-						return rs->sr_err;
-					}
-					break;
-				}
-				if ( changed )
-					break;
-			}
-			if ( !changed ) {
-				do_present = 0;
-no_change:		if ( !(op->o_sync_mode & SLAP_SYNC_PERSIST) ) {
-					LDAPControl	*ctrls[2];
-
-					ctrls[0] = NULL;
-					ctrls[1] = NULL;
-					syncprov_done_ctrl( op, rs, ctrls, 0, 0,
-						NULL, LDAP_SYNC_REFRESH_DELETES );
-					rs->sr_ctrls = ctrls;
-					rs->sr_err = LDAP_SUCCESS;
-					send_ldap_result( op, rs );
-					rs->sr_ctrls = NULL;
-					return rs->sr_err;
-				}
-				goto shortcut;
-			}
-		} else {
-			/* consumer doesn't have the right number of CSNs */
-			changed = SS_CHANGED;
+			goto shortcut;
 		}
 		/* Do we have a sessionlog for this search? */
 		sl=si->si_logs;
@@ -2522,10 +2037,10 @@ no_change:		if ( !(op->o_sync_mode & SLA
 			/* Are there any log entries, and is the consumer state
 			 * present in the session log?
 			 */
-			if ( sl->sl_num > 0 && ber_bvcmp( &mincsn, &sl->sl_mincsn ) >= 0 ) {
+			if ( sl->sl_num > 0 && ber_bvcmp( &srs->sr_state.ctxcsn, &sl->sl_mincsn ) >= 0 ) {
 				do_present = 0;
 				/* mutex is unlocked in playlog */
-				syncprov_playlog( op, rs, sl, srs, ctxcsn, numcsns, sids );
+				syncprov_playlog( op, rs, sl, srs, &ctxcsn );
 			} else {
 				ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
 			}
@@ -2535,38 +2050,18 @@ no_change:		if ( !(op->o_sync_mode & SLA
 			/* No, so a reload is required */
 			/* the 2.2 consumer doesn't send this hint */
 			if ( si->si_usehint && srs->sr_rhint == 0 ) {
-				if ( ctxcsn )
-					ber_bvarray_free_x( ctxcsn, op->o_tmpmemctx );
-				if ( sids )
-					op->o_tmpfree( sids, op->o_tmpmemctx );
-				rs->sr_err = LDAP_SYNC_REFRESH_REQUIRED;
-				rs->sr_text = "sync cookie is stale";
-				goto bailout;
-			}
-			if ( srs->sr_state.ctxcsn ) {
-				ber_bvarray_free_x( srs->sr_state.ctxcsn, op->o_tmpmemctx );
-				srs->sr_state.ctxcsn = NULL;
-			}
-			if ( srs->sr_state.sids ) {
-				slap_sl_free( srs->sr_state.sids, op->o_tmpmemctx );
-				srs->sr_state.sids = NULL;
+				send_ldap_error( op, rs, LDAP_SYNC_REFRESH_REQUIRED, "sync cookie is stale" );
+				return rs->sr_err;
 			}
-			srs->sr_state.numcsns = 0;
 		} else {
 			gotstate = 1;
 			/* If changed and doing Present lookup, send Present UUIDs */
 			if ( do_present && syncprov_findcsn( op, FIND_PRESENT ) !=
 				LDAP_SUCCESS ) {
-				if ( ctxcsn )
-					ber_bvarray_free_x( ctxcsn, op->o_tmpmemctx );
-				if ( sids )
-					op->o_tmpfree( sids, op->o_tmpmemctx );
-				goto bailout;
+				send_ldap_result( op, rs );
+				return rs->sr_err;
 			}
 		}
-	} else {
-		/* No consumer state, assume something has changed */
-		changed = SS_CHANGED;
 	}
 
 shortcut:
@@ -2578,7 +2073,7 @@ shortcut:
 	}
 
 	/* If something changed, find the changes */
-	if ( gotstate && changed ) {
+	if ( gotstate && !nochange ) {
 		Filter *fand, *fava;
 
 		fand = op->o_tmpalloc( sizeof(Filter), op->o_tmpmemctx );
@@ -2592,7 +2087,7 @@ shortcut:
 #ifdef LDAP_COMP_MATCH
 		fava->f_ava->aa_cf = NULL;
 #endif
-		ber_dupbv_x( &fava->f_ava->aa_value, &mincsn, op->o_tmpmemctx );
+		ber_dupbv_x( &fava->f_ava->aa_value, &srs->sr_state.ctxcsn, op->o_tmpmemctx );
 		fava->f_next = op->ors_filter;
 		op->ors_filter = fand;
 		filter2bv_x( op, op->ors_filter, &op->ors_filterstr );
@@ -2605,21 +2100,25 @@ shortcut:
 	ss = (searchstate *)(cb+1);
 	ss->ss_on = on;
 	ss->ss_so = sop;
-	ss->ss_flags = do_present | changed;
-	ss->ss_ctxcsn = ctxcsn;
-	ss->ss_numcsns = numcsns;
-	ss->ss_sids = sids;
+	ss->ss_present = do_present;
+	ss->ss_ctxcsn.bv_len = ctxcsn.bv_len;
+	ss->ss_ctxcsn.bv_val = ss->ss_csnbuf;
+	strcpy( ss->ss_ctxcsn.bv_val, ctxcsn.bv_val );
 	cb->sc_response = syncprov_search_response;
 	cb->sc_cleanup = syncprov_search_cleanup;
 	cb->sc_private = ss;
 	cb->sc_next = op->o_callback;
 	op->o_callback = cb;
 
+#if 0	/* I don't think we need to shortcircuit back-bdb any more */
+	op->o_sync_mode &= SLAP_CONTROL_MASK;
+#endif
+
 	/* If this is a persistent search and no changes were reported during
 	 * the refresh phase, just invoke the response callback to transition
 	 * us into persist phase
 	 */
-	if ( !changed ) {
+	if ( nochange ) {
 		rs->sr_err = LDAP_SUCCESS;
 		rs->sr_nentries = 0;
 		send_ldap_result( op, rs );
@@ -2636,14 +2135,8 @@ syncprov_operational(
 	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
 	syncprov_info_t		*si = (syncprov_info_t *)on->on_bi.bi_private;
 
-	/* This prevents generating unnecessarily; frontend will strip
-	 * any statically stored copy.
-	 */
-	if ( op->o_sync != SLAP_CONTROL_NONE )
-		return SLAP_CB_CONTINUE;
-
 	if ( rs->sr_entry &&
-		dn_match( &rs->sr_entry->e_nname, &si->si_contextdn )) {
+		dn_match( &rs->sr_entry->e_nname, op->o_bd->be_nsuffix )) {
 
 		if ( SLAP_OPATTRS( rs->sr_attr_flags ) ||
 			ad_inlist( slap_schema.si_ad_contextCSN, rs->sr_attrs )) {
@@ -2654,42 +2147,23 @@ syncprov_operational(
 					break;
 			}
 
-			ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
-			if ( si->si_ctxcsn ) {
-				if ( !a ) {
-					for ( ap = &rs->sr_operational_attrs; *ap;
-						ap=&(*ap)->a_next );
+			if ( !a ) {
+				for ( ap = &rs->sr_operational_attrs; *ap; ap=&(*ap)->a_next );
 
-					a = attr_alloc( slap_schema.si_ad_contextCSN );
-					*ap = a;
-				}
+				a = attr_alloc( slap_schema.si_ad_contextCSN );
+				a->a_vals = ch_malloc( 2 * sizeof(struct berval));
+				a->a_vals[1].bv_val = NULL;
+				a->a_nvals = a->a_vals;
+				*ap = a;
+			}
 
-				if ( !ap ) {
-					if ( !(rs->sr_flags & REP_ENTRY_MODIFIABLE) ) {
-						Entry *e = entry_dup( rs->sr_entry );
-						if ( rs->sr_flags & REP_ENTRY_MUSTRELEASE ) {
-							overlay_entry_release_ov( op, rs->sr_entry, 0, on );
-							rs->sr_flags ^= REP_ENTRY_MUSTRELEASE;
-						} else if ( rs->sr_flags & REP_ENTRY_MUSTBEFREED ) {
-							entry_free( rs->sr_entry );
-						}
-						rs->sr_entry = e;
-						rs->sr_flags |=
-							REP_ENTRY_MODIFIABLE|REP_ENTRY_MUSTBEFREED;
-						a = attr_find( rs->sr_entry->e_attrs,
-							slap_schema.si_ad_contextCSN );
-					}
-					if ( a->a_nvals != a->a_vals ) {
-						ber_bvarray_free( a->a_nvals );
-					}
-					a->a_nvals = NULL;
-					ber_bvarray_free( a->a_vals );
-					a->a_vals = NULL;
-					a->a_numvals = 0;
-				}
-				attr_valadd( a, si->si_ctxcsn, si->si_ctxcsn, si->si_numcsns );
+			ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+			if ( !ap ) {
+				strcpy( a->a_vals[0].bv_val, si->si_ctxcsnbuf );
+			} else {
+				ber_dupbv( &a->a_vals[0], &si->si_ctxcsn );
 			}
-			ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
+			ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
 		}
 	}
 	return SLAP_CB_CONTINUE;
@@ -2729,11 +2203,7 @@ static ConfigOCs spocs[] = {
 		"NAME 'olcSyncProvConfig' "
 		"DESC 'SyncRepl Provider configuration' "
 		"SUP olcOverlayConfig "
-		"MAY ( olcSpCheckpoint "
-			"$ olcSpSessionlog "
-			"$ olcSpNoPresent "
-			"$ olcSpReloadHint "
-		") )",
+		"MAY ( olcSpCheckpoint $ olcSpSessionlog $ olcSpNoPresent ) )",
 			Cft_Overlay, spcfg },
 	{ NULL, 0, NULL }
 };
@@ -2750,17 +2220,10 @@ sp_cf_gen(ConfigArgs *c)
 		case SP_CHKPT:
 			if ( si->si_chkops || si->si_chktime ) {
 				struct berval bv;
-				/* we assume si_chktime is a multiple of 60
-				 * because the parsed value was originally
-				 * multiplied by 60 */
-				bv.bv_len = snprintf( c->cr_msg, sizeof( c->cr_msg ),
-					"%d %d", si->si_chkops, si->si_chktime/60 );
-				if ( bv.bv_len >= sizeof( c->cr_msg ) ) {
-					rc = 1;
-				} else {
-					bv.bv_val = c->cr_msg;
-					value_add_one( &c->rvalue_vals, &bv );
-				}
+				bv.bv_len = sprintf( c->msg, "%d %d",
+					si->si_chkops, si->si_chktime );
+				bv.bv_val = c->msg;
+				value_add_one( &c->rvalue_vals, &bv );
 			} else {
 				rc = 1;
 			}
@@ -2818,31 +2281,31 @@ sp_cf_gen(ConfigArgs *c)
 	switch ( c->type ) {
 	case SP_CHKPT:
 		if ( lutil_atoi( &si->si_chkops, c->argv[1] ) != 0 ) {
-			snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s unable to parse checkpoint ops # \"%s\"",
+			snprintf( c->msg, sizeof( c->msg ), "%s unable to parse checkpoint ops # \"%s\"",
 				c->argv[0], c->argv[1] );
 			Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-				"%s: %s\n", c->log, c->cr_msg, 0 );
+				"%s: %s\n", c->log, c->msg, 0 );
 			return ARG_BAD_CONF;
 		}
 		if ( si->si_chkops <= 0 ) {
-			snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s invalid checkpoint ops # \"%d\"",
+			snprintf( c->msg, sizeof( c->msg ), "%s invalid checkpoint ops # \"%d\"",
 				c->argv[0], si->si_chkops );
 			Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-				"%s: %s\n", c->log, c->cr_msg, 0 );
+				"%s: %s\n", c->log, c->msg, 0 );
 			return ARG_BAD_CONF;
 		}
 		if ( lutil_atoi( &si->si_chktime, c->argv[2] ) != 0 ) {
-			snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s unable to parse checkpoint time \"%s\"",
+			snprintf( c->msg, sizeof( c->msg ), "%s unable to parse checkpoint time \"%s\"",
 				c->argv[0], c->argv[1] );
 			Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-				"%s: %s\n", c->log, c->cr_msg, 0 );
+				"%s: %s\n", c->log, c->msg, 0 );
 			return ARG_BAD_CONF;
 		}
 		if ( si->si_chktime <= 0 ) {
-			snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s invalid checkpoint time \"%d\"",
+			snprintf( c->msg, sizeof( c->msg ), "%s invalid checkpoint time \"%d\"",
 				c->argv[0], si->si_chkops );
 			Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-				"%s: %s\n", c->log, c->cr_msg, 0 );
+				"%s: %s\n", c->log, c->msg, 0 );
 			return ARG_BAD_CONF;
 		}
 		si->si_chktime *= 60;
@@ -2852,15 +2315,15 @@ sp_cf_gen(ConfigArgs *c)
 		int size = c->value_int;
 
 		if ( size < 0 ) {
-			snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s size %d is negative",
+			snprintf( c->msg, sizeof( c->msg ), "%s size %d is negative",
 				c->argv[0], size );
 			Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-				"%s: %s\n", c->log, c->cr_msg, 0 );
+				"%s: %s\n", c->log, c->msg, 0 );
 			return ARG_BAD_CONF;
 		}
 		sl = si->si_logs;
 		if ( !sl ) {
-			sl = ch_malloc( sizeof( sessionlog ) + LDAP_PVT_CSNSTR_BUFSIZE );
+			sl = ch_malloc( sizeof( sessionlog ) + LDAP_LUTIL_CSNSTR_BUFSIZE );
 			sl->sl_mincsn.bv_val = (char *)(sl+1);
 			sl->sl_mincsn.bv_len = 0;
 			sl->sl_num = 0;
@@ -2899,17 +2362,17 @@ syncprov_db_otask(
  */
 static int
 syncprov_db_open(
-	BackendDB *be,
-	ConfigReply *cr
+    BackendDB *be
 )
 {
 	slap_overinst   *on = (slap_overinst *) be->bd_info;
 	syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
 
 	Connection conn = { 0 };
-	OperationBuffer opbuf;
-	Operation *op;
-	Entry *e = NULL;
+	OperationBuffer opbuf = { 0 };
+	char ctxcsnbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
+	Operation *op = (Operation *) &opbuf;
+	Entry *e;
 	Attribute *a;
 	int rc;
 	void *thrctx = NULL;
@@ -2930,32 +2393,33 @@ syncprov_db_open(
 	}
 
 	thrctx = ldap_pvt_thread_pool_context();
-	connection_fake_init2( &conn, &opbuf, thrctx, 0 );
-	op = &opbuf.ob_op;
+	connection_fake_init( &conn, op, thrctx );
 	op->o_bd = be;
 	op->o_dn = be->be_rootdn;
 	op->o_ndn = be->be_rootndn;
 
-	if ( SLAP_SYNC_SUBENTRY( be )) {
-		build_new_dn( &si->si_contextdn, be->be_nsuffix,
-			(struct berval *)&slap_ldapsync_cn_bv, NULL );
-	} else {
-		si->si_contextdn = be->be_nsuffix[0];
-	}
-	rc = overlay_entry_get_ov( op, &si->si_contextdn, NULL,
-		slap_schema.si_ad_contextCSN, 0, &e, on );
+	ctxcsnbuf[0] = '\0';
+
+	op->o_bd->bd_info = on->on_info->oi_orig;
+	rc = be_entry_get_rw( op, be->be_nsuffix, NULL,
+		slap_schema.si_ad_contextCSN, 0, &e );
 
 	if ( e ) {
 		ldap_pvt_thread_t tid;
 
 		a = attr_find( e->e_attrs, slap_schema.si_ad_contextCSN );
 		if ( a ) {
-			ber_bvarray_dup_x( &si->si_ctxcsn, a->a_vals, NULL );
-			si->si_numcsns = a->a_numvals;
-			si->si_sids = slap_parse_csn_sids( si->si_ctxcsn, a->a_numvals, NULL );
-		}
-		overlay_entry_release_ov( op, e, 0, on );
-		if ( si->si_ctxcsn && !SLAP_DBCLEAN( be )) {
+			si->si_ctxcsn.bv_len = a->a_nvals[0].bv_len;
+			if ( si->si_ctxcsn.bv_len >= sizeof(si->si_ctxcsnbuf ))
+				si->si_ctxcsn.bv_len = sizeof(si->si_ctxcsnbuf)-1;
+			strncpy( si->si_ctxcsnbuf, a->a_nvals[0].bv_val,
+				si->si_ctxcsn.bv_len );
+			si->si_ctxcsnbuf[si->si_ctxcsn.bv_len] = '\0';
+			strcpy( ctxcsnbuf, si->si_ctxcsnbuf );
+		}
+		be_entry_release_rw( op, e, 0 );
+		if ( !BER_BVISEMPTY( &si->si_ctxcsn ) ) {
+			op->o_bd->bd_info = (BackendInfo *)on;
 			op->o_req_dn = be->be_suffix[0];
 			op->o_req_ndn = be->be_nsuffix[0];
 			op->ors_scope = LDAP_SCOPE_SUBTREE;
@@ -2964,32 +2428,28 @@ syncprov_db_open(
 		}
 	}
 
-	/* Didn't find a contextCSN, should we generate one? */
-	if ( !si->si_ctxcsn ) {
-		char csnbuf[ LDAP_PVT_CSNSTR_BUFSIZE ];
-		struct berval csn;
-
+	if ( BER_BVISEMPTY( &si->si_ctxcsn ) ) {
 		if ( SLAP_SYNC_SHADOW( op->o_bd )) {
-		/* If we're also a consumer, then don't generate anything.
-		 * Wait for our provider to send it to us, or for a local
-		 * modify if we have multimaster.
+		/* If we're also a consumer, and we didn't get a contextCSN,
+		 * then don't generate anything, wait for our provider to send it
+		 * to us.
 		 */
 			goto out;
 		}
-		csn.bv_val = csnbuf;
-		csn.bv_len = sizeof( csnbuf );
-		slap_get_csn( op, &csn, 0 );
-		value_add_one( &si->si_ctxcsn, &csn );
-		si->si_numcsns = 1;
-		si->si_sids = ch_malloc( sizeof(int) );
-		si->si_sids[0] = slap_serverID;
+		si->si_ctxcsn.bv_len = sizeof( si->si_ctxcsnbuf );
+		slap_get_csn( op, &si->si_ctxcsn, 0 );
+	}
 
-		/* make sure we do a checkpoint on close */
+	/* If our ctxcsn is different from what was read from the root
+	 * entry, make sure we do a checkpoint on close
+	 */
+	if ( strcmp( si->si_ctxcsnbuf, ctxcsnbuf )) {
 		si->si_numops++;
 	}
 
 out:
 	op->o_bd->bd_info = (BackendInfo *)on;
+	ldap_pvt_thread_pool_context_reset( thrctx );
 	return 0;
 }
 
@@ -2997,8 +2457,7 @@ out:
  */
 static int
 syncprov_db_close(
-	BackendDB *be,
-	ConfigReply *cr
+    BackendDB *be
 )
 {
     slap_overinst   *on = (slap_overinst *) be->bd_info;
@@ -3008,19 +2467,19 @@ syncprov_db_close(
 		return 0;
 	}
 	if ( si->si_numops ) {
-		Connection conn = {0};
+		Connection conn;
 		OperationBuffer opbuf;
-		Operation *op;
+		Operation *op = (Operation *) &opbuf;
 		SlapReply rs = {REP_RESULT};
 		void *thrctx;
 
 		thrctx = ldap_pvt_thread_pool_context();
-		connection_fake_init2( &conn, &opbuf, thrctx, 0 );
-		op = &opbuf.ob_op;
+		connection_fake_init( &conn, op, thrctx );
 		op->o_bd = be;
 		op->o_dn = be->be_rootdn;
 		op->o_ndn = be->be_rootndn;
-		syncprov_checkpoint( op, &rs, on );
+		syncprov_checkpoint( op, &rs, on, &si->si_ctxcsn );
+		ldap_pvt_thread_pool_context_reset( thrctx );
 	}
 
     return 0;
@@ -3028,8 +2487,7 @@ syncprov_db_close(
 
 static int
 syncprov_db_init(
-	BackendDB *be,
-	ConfigReply *cr
+	BackendDB *be
 )
 {
 	slap_overinst	*on = (slap_overinst *)be->bd_info;
@@ -3044,10 +2502,10 @@ syncprov_db_init(
 
 	si = ch_calloc(1, sizeof(syncprov_info_t));
 	on->on_bi.bi_private = si;
-	ldap_pvt_thread_rdwr_init( &si->si_csn_rwlock );
+	ldap_pvt_thread_mutex_init( &si->si_csn_mutex );
 	ldap_pvt_thread_mutex_init( &si->si_ops_mutex );
 	ldap_pvt_thread_mutex_init( &si->si_mods_mutex );
-	ldap_pvt_thread_mutex_init( &si->si_resp_mutex );
+	si->si_ctxcsn.bv_val = si->si_ctxcsnbuf;
 
 	csn_anlist[0].an_desc = slap_schema.si_ad_entryCSN;
 	csn_anlist[0].an_name = slap_schema.si_ad_entryCSN->ad_cname;
@@ -3062,8 +2520,7 @@ syncprov_db_init(
 
 static int
 syncprov_db_destroy(
-	BackendDB *be,
-	ConfigReply *cr
+	BackendDB *be
 )
 {
 	slap_overinst	*on = (slap_overinst *)be->bd_info;
@@ -3081,14 +2538,9 @@ syncprov_db_destroy(
 				
 			ch_free( si->si_logs );
 		}
-		if ( si->si_ctxcsn )
-			ber_bvarray_free( si->si_ctxcsn );
-		if ( si->si_sids )
-			ch_free( si->si_sids );
-		ldap_pvt_thread_mutex_destroy( &si->si_resp_mutex );
 		ldap_pvt_thread_mutex_destroy( &si->si_mods_mutex );
 		ldap_pvt_thread_mutex_destroy( &si->si_ops_mutex );
-		ldap_pvt_thread_rdwr_destroy( &si->si_csn_rwlock );
+		ldap_pvt_thread_mutex_destroy( &si->si_csn_mutex );
 		ch_free( si );
 	}
 
@@ -3119,13 +2571,8 @@ static int syncprov_parseCtrl (
 		return LDAP_PROTOCOL_ERROR;
 	}
 
-	if ( BER_BVISNULL( &ctrl->ldctl_value ) ) {
-		rs->sr_text = "Sync control value is absent";
-		return LDAP_PROTOCOL_ERROR;
-	}
-
 	if ( BER_BVISEMPTY( &ctrl->ldctl_value ) ) {
-		rs->sr_text = "Sync control value is empty";
+		rs->sr_text = "Sync control value is empty (or absent)";
 		return LDAP_PROTOCOL_ERROR;
 	}
 
@@ -3183,14 +2630,10 @@ static int syncprov_parseCtrl (
 	sr->sr_rhint = rhint;
 	if (!BER_BVISNULL(&cookie)) {
 		ber_dupbv_x( &sr->sr_state.octet_str, &cookie, op->o_tmpmemctx );
-		/* If parse fails, pretend no cookie was sent */
-		if ( slap_parse_sync_cookie( &sr->sr_state, op->o_tmpmemctx ) ||
-			sr->sr_state.rid == -1 ) {
-			if ( sr->sr_state.ctxcsn ) {
-				ber_bvarray_free_x( sr->sr_state.ctxcsn, op->o_tmpmemctx );
-				sr->sr_state.ctxcsn = NULL;
-			}
-			sr->sr_state.numcsns = 0;
+		slap_parse_sync_cookie( &sr->sr_state, op->o_tmpmemctx );
+		if ( sr->sr_state.rid == -1 ) {
+			rs->sr_text = "Sync control : cookie parsing error";
+			return LDAP_PROTOCOL_ERROR;
 		}
 	}