ITS#8486 use kbtree for sessionlog

Saves about 20% CPU time and RAM

include/kbtree.h

+/*-
+ * Copyright 1997-1999, 2001, John-Mark Gurney.
+ *           2008-2009, Attractive Chaos <attractor@live.co.uk>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __AC_KBTREE_H
+#define __AC_KBTREE_H
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#define KB_MAX_DEPTH 64
+
+typedef struct {
+	int32_t is_internal:1, n:31;
+} kbnode_t;
+
+typedef struct {
+	kbnode_t *x;
+	int i;
+} kbpos_t;
+
+typedef struct {
+	kbpos_t stack[KB_MAX_DEPTH], *p;
+} kbitr_t;
+
+#define	__KB_KEY(type, x)	((type*)((char*)x + 4))
+#define __KB_PTR(btr, x)	((kbnode_t**)((char*)x + btr->off_ptr))
+
+#define __KB_TREE_T(name)						\
+	typedef struct {							\
+		kbnode_t *root;							\
+		int	off_key, off_ptr, ilen, elen;		\
+		int	n, t;								\
+		int	n_keys, n_nodes;					\
+	} kbtree_##name##_t;
+
+#define __KB_INIT(name, key_t)											\
+	kbtree_##name##_t *kb_init_##name(int size)							\
+	{																	\
+		kbtree_##name##_t *b;											\
+		b = (kbtree_##name##_t*)calloc(1, sizeof(kbtree_##name##_t));	\
+		b->t = ((size - 4 - sizeof(void*)) / (sizeof(void*) + sizeof(key_t)) + 1) >> 1; \
+		if (b->t < 2) {													\
+			free(b); return 0;											\
+		}																\
+		b->n = 2 * b->t - 1;											\
+		b->off_ptr = 4 + b->n * sizeof(key_t);							\
+		b->ilen = (4 + sizeof(void*) + b->n * (sizeof(void*) + sizeof(key_t)) + 3) >> 2 << 2; \
+		b->elen = (b->off_ptr + 3) >> 2 << 2;							\
+		b->root = (kbnode_t*)calloc(1, b->ilen);						\
+		++b->n_nodes;													\
+		return b;														\
+	}
+
+#define __kb_destroy(b) do {											\
+		int i, max = 8;													\
+		kbnode_t *x, **top, **stack = 0;								\
+		if (b) {														\
+			top = stack = (kbnode_t**)calloc(max, sizeof(kbnode_t*));	\
+			*top++ = (b)->root;											\
+			while (top != stack) {										\
+				x = *--top;												\
+				if (x->is_internal == 0) { free(x); continue; }			\
+				for (i = 0; i <= x->n; ++i)								\
+					if (__KB_PTR(b, x)[i]) {							\
+						if (top - stack == max) {						\
+							max <<= 1;									\
+							stack = (kbnode_t**)realloc(stack, max * sizeof(kbnode_t*)); \
+							top = stack + (max>>1);						\
+						}												\
+						*top++ = __KB_PTR(b, x)[i];						\
+					}													\
+				free(x);												\
+			}															\
+		}																\
+		free(b); free(stack);											\
+	} while (0)
+
+#define __KB_GET_AUX1(name, key_t, __cmp)								\
+	static inline int __kb_getp_aux_##name(const kbnode_t * __restrict x, const key_t * __restrict k, int *r) \
+	{																	\
+		int tr, *rr, begin = 0, end = x->n;								\
+		if (x->n == 0) return -1;										\
+		rr = r? r : &tr;												\
+		while (begin < end) {											\
+			int mid = (begin + end) >> 1;								\
+			if (__cmp(__KB_KEY(key_t, x)[mid], *k) < 0) begin = mid + 1; \
+			else end = mid;												\
+		}																\
+		if (begin == x->n) { *rr = 1; return x->n - 1; }				\
+		if ((*rr = __cmp(*k, __KB_KEY(key_t, x)[begin])) < 0) --begin;	\
+		return begin;													\
+	}
+
+#define __KB_GET(name, key_t)											\
+	static key_t *kb_getp_##name(kbtree_##name##_t *b, const key_t * __restrict k) \
+	{																	\
+		int i, r = 0;													\
+		kbnode_t *x = b->root;											\
+		while (x) {														\
+			i = __kb_getp_aux_##name(x, k, &r);							\
+			if (i >= 0 && r == 0) return &__KB_KEY(key_t, x)[i];		\
+			if (x->is_internal == 0) return 0;							\
+			x = __KB_PTR(b, x)[i + 1];									\
+		}																\
+		return 0;														\
+	}																	\
+	static inline key_t *kb_get_##name(kbtree_##name##_t *b, const key_t k) \
+	{																	\
+		return kb_getp_##name(b, &k);									\
+	}
+
+#define __KB_INTERVAL(name, key_t)										\
+	static void kb_intervalp_##name(kbtree_##name##_t *b, const key_t * __restrict k, key_t **lower, key_t **upper)	\
+	{																	\
+		int i, r = 0;													\
+		kbnode_t *x = b->root;											\
+		*lower = *upper = 0;											\
+		while (x) {														\
+			i = __kb_getp_aux_##name(x, k, &r);							\
+			if (i >= 0 && r == 0) {										\
+				*lower = *upper = &__KB_KEY(key_t, x)[i];				\
+				return;													\
+			}															\
+			if (i >= 0) *lower = &__KB_KEY(key_t, x)[i];				\
+			if (i < x->n - 1) *upper = &__KB_KEY(key_t, x)[i + 1];		\
+			if (x->is_internal == 0) return;							\
+			x = __KB_PTR(b, x)[i + 1];									\
+		}																\
+	}																	\
+	static inline void kb_interval_##name(kbtree_##name##_t *b, const key_t k, key_t **lower, key_t **upper) \
+	{																	\
+		kb_intervalp_##name(b, &k, lower, upper);						\
+	}
+
+#define __KB_PUT(name, key_t, __cmp)									\
+	/* x must be an internal node */									\
+	static void __kb_split_##name(kbtree_##name##_t *b, kbnode_t *x, int i, kbnode_t *y) \
+	{																	\
+		kbnode_t *z;													\
+		z = (kbnode_t*)calloc(1, y->is_internal? b->ilen : b->elen);	\
+		++b->n_nodes;													\
+		z->is_internal = y->is_internal;								\
+		z->n = b->t - 1;												\
+		memcpy(__KB_KEY(key_t, z), __KB_KEY(key_t, y) + b->t, sizeof(key_t) * (b->t - 1)); \
+		if (y->is_internal) memcpy(__KB_PTR(b, z), __KB_PTR(b, y) + b->t, sizeof(void*) * b->t); \
+		y->n = b->t - 1;												\
+		memmove(__KB_PTR(b, x) + i + 2, __KB_PTR(b, x) + i + 1, sizeof(void*) * (x->n - i)); \
+		__KB_PTR(b, x)[i + 1] = z;										\
+		memmove(__KB_KEY(key_t, x) + i + 1, __KB_KEY(key_t, x) + i, sizeof(key_t) * (x->n - i)); \
+		__KB_KEY(key_t, x)[i] = __KB_KEY(key_t, y)[b->t - 1];			\
+		++x->n;															\
+	}																	\
+	static key_t *__kb_putp_aux_##name(kbtree_##name##_t *b, kbnode_t *x, const key_t * __restrict k) \
+	{																	\
+		int i = x->n - 1;												\
+		key_t *ret;														\
+		if (x->is_internal == 0) {										\
+			i = __kb_getp_aux_##name(x, k, 0);							\
+			if (i != x->n - 1)											\
+				memmove(__KB_KEY(key_t, x) + i + 2, __KB_KEY(key_t, x) + i + 1, (x->n - i - 1) * sizeof(key_t)); \
+			ret = &__KB_KEY(key_t, x)[i + 1];							\
+			*ret = (key_t)*k;													\
+			++x->n;														\
+		} else {														\
+			i = __kb_getp_aux_##name(x, k, 0) + 1;						\
+			if (__KB_PTR(b, x)[i]->n == 2 * b->t - 1) {					\
+				__kb_split_##name(b, x, i, __KB_PTR(b, x)[i]);			\
+				if (__cmp(*k, __KB_KEY(key_t, x)[i]) > 0) ++i;			\
+			}															\
+			ret = __kb_putp_aux_##name(b, __KB_PTR(b, x)[i], k);		\
+		}																\
+		return ret; 													\
+	}																	\
+	static key_t *kb_putp_##name(kbtree_##name##_t *b, const key_t * __restrict k) \
+	{																	\
+		kbnode_t *r, *s;												\
+		++b->n_keys;													\
+		r = b->root;													\
+		if (r->n == 2 * b->t - 1) {										\
+			++b->n_nodes;												\
+			s = (kbnode_t*)calloc(1, b->ilen);							\
+			b->root = s; s->is_internal = 1; s->n = 0;					\
+			__KB_PTR(b, s)[0] = r;										\
+			__kb_split_##name(b, s, 0, r);								\
+			r = s;														\
+		}																\
+		return __kb_putp_aux_##name(b, r, k);							\
+	}																	\
+	static inline void kb_put_##name(kbtree_##name##_t *b, const key_t k) \
+	{																	\
+		kb_putp_##name(b, &k);											\
+	}
+
+
+#define __KB_DEL(name, key_t)											\
+	static key_t __kb_delp_aux_##name(kbtree_##name##_t *b, kbnode_t *x, const key_t * __restrict k, int s) \
+	{																	\
+		int yn, zn, i, r = 0;											\
+		kbnode_t *xp, *y, *z;											\
+		key_t kp;														\
+		if (x == 0) return (key_t)*k;											\
+		if (s) { /* s can only be 0, 1 or 2 */							\
+			r = x->is_internal == 0? 0 : s == 1? 1 : -1;				\
+			i = s == 1? x->n - 1 : -1;									\
+		} else i = __kb_getp_aux_##name(x, k, &r);						\
+		if (x->is_internal == 0) {										\
+			if (s == 2) ++i;											\
+			kp = __KB_KEY(key_t, x)[i];									\
+			memmove(__KB_KEY(key_t, x) + i, __KB_KEY(key_t, x) + i + 1, (x->n - i - 1) * sizeof(key_t)); \
+			--x->n;														\
+			return kp;													\
+		}																\
+		if (r == 0) {													\
+			if ((yn = __KB_PTR(b, x)[i]->n) >= b->t) {					\
+				xp = __KB_PTR(b, x)[i];									\
+				kp = __KB_KEY(key_t, x)[i];								\
+				__KB_KEY(key_t, x)[i] = __kb_delp_aux_##name(b, xp, 0, 1); \
+				return kp;												\
+			} else if ((zn = __KB_PTR(b, x)[i + 1]->n) >= b->t) {		\
+				xp = __KB_PTR(b, x)[i + 1];								\
+				kp = __KB_KEY(key_t, x)[i];								\
+				__KB_KEY(key_t, x)[i] = __kb_delp_aux_##name(b, xp, 0, 2); \
+				return kp;												\
+			} else if (yn == b->t - 1 && zn == b->t - 1) {				\
+				y = __KB_PTR(b, x)[i]; z = __KB_PTR(b, x)[i + 1];		\
+				__KB_KEY(key_t, y)[y->n++] = (key_t)*k;						\
+				memmove(__KB_KEY(key_t, y) + y->n, __KB_KEY(key_t, z), z->n * sizeof(key_t)); \
+				if (y->is_internal) memmove(__KB_PTR(b, y) + y->n, __KB_PTR(b, z), (z->n + 1) * sizeof(void*)); \
+				y->n += z->n;											\
+				memmove(__KB_KEY(key_t, x) + i, __KB_KEY(key_t, x) + i + 1, (x->n - i - 1) * sizeof(key_t)); \
+				memmove(__KB_PTR(b, x) + i + 1, __KB_PTR(b, x) + i + 2, (x->n - i - 1) * sizeof(void*)); \
+				--x->n;													\
+				free(z);												\
+				return __kb_delp_aux_##name(b, y, k, s);				\
+			}															\
+		}																\
+		++i;															\
+		if ((xp = __KB_PTR(b, x)[i])->n == b->t - 1) {					\
+			if (i > 0 && (y = __KB_PTR(b, x)[i - 1])->n >= b->t) {		\
+				memmove(__KB_KEY(key_t, xp) + 1, __KB_KEY(key_t, xp), xp->n * sizeof(key_t)); \
+				if (xp->is_internal) memmove(__KB_PTR(b, xp) + 1, __KB_PTR(b, xp), (xp->n + 1) * sizeof(void*)); \
+				__KB_KEY(key_t, xp)[0] = __KB_KEY(key_t, x)[i - 1];		\
+				__KB_KEY(key_t, x)[i - 1] = __KB_KEY(key_t, y)[y->n - 1]; \
+				if (xp->is_internal) __KB_PTR(b, xp)[0] = __KB_PTR(b, y)[y->n]; \
+				--y->n; ++xp->n;										\
+			} else if (i < x->n && (y = __KB_PTR(b, x)[i + 1])->n >= b->t) { \
+				__KB_KEY(key_t, xp)[xp->n++] = __KB_KEY(key_t, x)[i];	\
+				__KB_KEY(key_t, x)[i] = __KB_KEY(key_t, y)[0];			\
+				if (xp->is_internal) __KB_PTR(b, xp)[xp->n] = __KB_PTR(b, y)[0]; \
+				--y->n;													\
+				memmove(__KB_KEY(key_t, y), __KB_KEY(key_t, y) + 1, y->n * sizeof(key_t)); \
+				if (y->is_internal) memmove(__KB_PTR(b, y), __KB_PTR(b, y) + 1, (y->n + 1) * sizeof(void*)); \
+			} else if (i > 0 && (y = __KB_PTR(b, x)[i - 1])->n == b->t - 1) { \
+				__KB_KEY(key_t, y)[y->n++] = __KB_KEY(key_t, x)[i - 1];	\
+				memmove(__KB_KEY(key_t, y) + y->n, __KB_KEY(key_t, xp), xp->n * sizeof(key_t));	\
+				if (y->is_internal) memmove(__KB_PTR(b, y) + y->n, __KB_PTR(b, xp), (xp->n + 1) * sizeof(void*)); \
+				y->n += xp->n;											\
+				memmove(__KB_KEY(key_t, x) + i - 1, __KB_KEY(key_t, x) + i, (x->n - i) * sizeof(key_t)); \
+				memmove(__KB_PTR(b, x) + i, __KB_PTR(b, x) + i + 1, (x->n - i) * sizeof(void*)); \
+				--x->n;													\
+				free(xp);												\
+				xp = y;													\
+			} else if (i < x->n && (y = __KB_PTR(b, x)[i + 1])->n == b->t - 1) { \
+				__KB_KEY(key_t, xp)[xp->n++] = __KB_KEY(key_t, x)[i];	\
+				memmove(__KB_KEY(key_t, xp) + xp->n, __KB_KEY(key_t, y), y->n * sizeof(key_t));	\
+				if (xp->is_internal) memmove(__KB_PTR(b, xp) + xp->n, __KB_PTR(b, y), (y->n + 1) * sizeof(void*)); \
+				xp->n += y->n;											\
+				memmove(__KB_KEY(key_t, x) + i, __KB_KEY(key_t, x) + i + 1, (x->n - i - 1) * sizeof(key_t)); \
+				memmove(__KB_PTR(b, x) + i + 1, __KB_PTR(b, x) + i + 2, (x->n - i - 1) * sizeof(void*)); \
+				--x->n;													\
+				free(y);												\
+			}															\
+		}																\
+		return __kb_delp_aux_##name(b, xp, k, s);						\
+	}																	\
+	static key_t kb_delp_##name(kbtree_##name##_t *b, const key_t * __restrict k) \
+	{																	\
+		kbnode_t *x;													\
+		key_t ret;														\
+		ret = __kb_delp_aux_##name(b, b->root, k, 0);					\
+		--b->n_keys;													\
+		if (b->root->n == 0 && b->root->is_internal) {					\
+			--b->n_nodes;												\
+			x = b->root;												\
+			b->root = __KB_PTR(b, x)[0];								\
+			free(x);													\
+		}																\
+		return ret;														\
+	}																	\
+	static inline key_t kb_del_##name(kbtree_##name##_t *b, const key_t k) \
+	{																	\
+		return kb_delp_##name(b, &k);									\
+	}
+
+#define __KB_ITR(name, key_t) \
+	static inline void kb_itr_first_##name(kbtree_##name##_t *b, kbitr_t *itr) \
+	{ \
+		itr->p = 0; \
+		if (b->n_keys == 0) return; \
+		itr->p = itr->stack; \
+		itr->p->x = b->root; itr->p->i = 0; \
+		while (itr->p->x->is_internal && __KB_PTR(b, itr->p->x)[0] != 0) { \
+			kbnode_t *x = itr->p->x; \
+			++itr->p; \
+			itr->p->x = __KB_PTR(b, x)[0]; itr->p->i = 0; \
+		} \
+	} \
+	static int kb_itr_get_##name(kbtree_##name##_t *b, const key_t * __restrict k, kbitr_t *itr) \
+	{ \
+		int i, r = 0; \
+		itr->p = itr->stack; \
+		itr->p->x = b->root; itr->p->i = 0; \
+		while (itr->p->x) { \
+			i = __kb_getp_aux_##name(itr->p->x, k, &r); \
+			if (i >= 0 && r == 0) return 0; \
+			if (itr->p->x->is_internal == 0) return -1; \
+			itr->p[1].x = __KB_PTR(b, itr->p->x)[i + 1]; \
+			itr->p[1].i = i; \
+			++itr->p; \
+		} \
+		return -1; \
+	} \
+	static inline int kb_itr_next_##name(kbtree_##name##_t *b, kbitr_t *itr) \
+	{ \
+		if (itr->p < itr->stack) return 0; \
+		for (;;) { \
+			++itr->p->i; \
+			while (itr->p->x && itr->p->i <= itr->p->x->n) { \
+				itr->p[1].i = 0; \
+				itr->p[1].x = itr->p->x->is_internal? __KB_PTR(b, itr->p->x)[itr->p->i] : 0; \
+				++itr->p; \
+			} \
+			--itr->p; \
+			if (itr->p < itr->stack) return 0; \
+			if (itr->p->x && itr->p->i < itr->p->x->n) return 1; \
+		} \
+	}
+
+#define KBTREE_INIT(name, key_t, __cmp)			\
+	__KB_TREE_T(name)							\
+	__KB_INIT(name, key_t)						\
+	__KB_GET_AUX1(name, key_t, __cmp)			\
+	__KB_GET(name, key_t)						\
+	__KB_INTERVAL(name, key_t)					\
+	__KB_PUT(name, key_t, __cmp)				\
+	__KB_DEL(name, key_t) \
+	__KB_ITR(name, key_t)
+
+#define KB_DEFAULT_SIZE 512
+
+#define kbtree_t(name) kbtree_##name##_t
+#define kb_init(name, s) kb_init_##name(s)
+#define kb_destroy(name, b) __kb_destroy(b)
+#define kb_get(name, b, k) kb_get_##name(b, k)
+#define kb_put(name, b, k) kb_put_##name(b, k)
+#define kb_del(name, b, k) kb_del_##name(b, k)
+#define kb_interval(name, b, k, l, u) kb_interval_##name(b, k, l, u)
+#define kb_getp(name, b, k) kb_getp_##name(b, k)
+#define kb_putp(name, b, k) kb_putp_##name(b, k)
+#define kb_delp(name, b, k) kb_delp_##name(b, k)
+#define kb_intervalp(name, b, k, l, u) kb_intervalp_##name(b, k, l, u)
+
+#define kb_itr_first(name, b, i) kb_itr_first_##name(b, i)
+#define kb_itr_get(name, b, k, i) kb_itr_get_##name(b, k, i)
+#define kb_itr_next(name, b, i) kb_itr_next_##name(b, i)
+#define kb_itr_key(type, itr) __KB_KEY(type, (itr)->p->x)[(itr)->p->i]
+#define kb_itr_valid(itr) ((itr)->p >= (itr)->stack)
+
+#define kb_size(b) ((b)->n_keys)
+
+#define kb_generic_cmp(a, b) (((b) < (a)) - ((a) < (b)))
+#define kb_str_cmp(a, b) strcmp(a, b)
+
+/* The following is *DEPRECATED*!!! Use the iterator interface instead! */
+
+typedef struct {
+	kbnode_t *x;
+	int i;
+} __kbstack_t;
+
+#define __kb_traverse(key_t, b, __func) do {							\
+		int __kmax = 8;													\
+		__kbstack_t *__kstack, *__kp;									\
+		__kp = __kstack = (__kbstack_t*)calloc(__kmax, sizeof(__kbstack_t)); \
+		__kp->x = (b)->root; __kp->i = 0;								\
+		for (;;) {														\
+			while (__kp->x && __kp->i <= __kp->x->n) {					\
+				if (__kp - __kstack == __kmax - 1) {					\
+					__kmax <<= 1;										\
+					__kstack = (__kbstack_t*)realloc(__kstack, __kmax * sizeof(__kbstack_t)); \
+					__kp = __kstack + (__kmax>>1) - 1;					\
+				}														\
+				(__kp+1)->i = 0; (__kp+1)->x = __kp->x->is_internal? __KB_PTR(b, __kp->x)[__kp->i] : 0; \
+				++__kp;													\
+			}															\
+			--__kp;														\
+			if (__kp >= __kstack) {										\
+				if (__kp->x && __kp->i < __kp->x->n) __func(&__KB_KEY(key_t, __kp->x)[__kp->i]); \
+				++__kp->i;												\
+			} else break;												\
+		}																\
+		free(__kstack);													\
+	} while (0)
+
+#define __kb_get_first(key_t, b, ret) do {	\
+		kbnode_t *__x = (b)->root;			\
+		while (__KB_PTR(b, __x)[0] != 0)	\
+			__x = __KB_PTR(b, __x)[0];		\
+		(ret) = __KB_KEY(key_t, __x)[0];	\
+	} while (0)
+
+#endif

servers/slapd/overlays/syncprov.c

@@ -27,6 +27,7 @@
 #include "slap.h"
 #include "config.h"
 #include "ldap_rq.h"
+#include "kbtree.h"
 
 #ifdef LDAP_DEVEL
 #define	CHECK_CSN	1
@@ -124,6 +125,14 @@ typedef struct slog_entry {
 	ber_tag_t	se_tag;
 } slog_entry;
 
+static int syncprov_sessionlog_cmp( const void *l, const void *r );
+
+#ifndef SLOG_BTSIZE
+#define SLOG_BTSIZE	1024
+#endif
+
+KBTREE_INIT(slog, slog_entry*, syncprov_sessionlog_cmp)
+
 typedef struct sessionlog {
 	BerVarray	sl_mincsn;
 	int		*sl_sids;
@@ -131,7 +140,7 @@ typedef struct sessionlog {
 	int		sl_num;
 	int		sl_size;
 	int		sl_playing;
-	TAvlnode *sl_entries;
+	kbtree_t(slog) *sl_entries;
 	ldap_pvt_thread_rdwr_t sl_mutex;
 } sessionlog;
 
@@ -433,24 +442,18 @@ syncprov_sessionlog_cmp( const void *l, const void *r )
 	int ret = ber_bvcmp( &left->se_csn, &right->se_csn );
 	if ( !ret )
 		ret = ber_bvcmp( &left->se_uuid, &right->se_uuid );
+	/* Only time we have two modifications with same CSN is when we detect a
+	 * rename during replication.
+	 * We invert the test here because LDAP_REQ_MODDN is
+	 * numerically greater than LDAP_REQ_MODIFY but we
+	 * want it to occur first.
+	 */
+	if ( !ret )
+		ret = right->se_tag - left->se_tag;
 
 	return ret;
 }
 
-static int
-syncprov_sessionlog_dup( void *o, void *n )
-{
-	slog_entry *old = o, *new = n;
-
-	/* Only time we have two modifications with same CSN is when we detect a
-	 * rename during replication */
-	/* FIXME: Does that imply a consumer coming just between we apply the mod
-	 * and the modify might only receive the former and never hear of the
-	 * latter? */
-	return old->se_tag != LDAP_REQ_MODRDN ||
-		new->se_tag != LDAP_REQ_MODIFY;
-}
-
 /* syncprov_findbase:
  *   finds the true DN of the base of a search (with alias dereferencing) and
  * checks to make sure the base entry doesn't get replaced with a different
@@ -1633,6 +1636,21 @@ syncprov_checkpoint( Operation *op, slap_overinst *on )
 #endif
 }
 
+static void
+syncprov_free_slog( kbtree_t(slog) *bt )
+{
+	kbitr_t itr;
+	slog_entry *se;
+
+	for ( kb_itr_first( slog, bt, &itr );
+		kb_itr_valid( &itr );
+		kb_itr_next( slog, bt, &itr )) {
+		se = kb_itr_key( slog_entry*, &itr );
+		ch_free( se );
+	}
+	kb_destroy( slog, bt );
+}
+
 static void
 syncprov_add_slog( Operation *op )
 {
@@ -1654,7 +1672,7 @@ syncprov_add_slog( Operation *op )
 			ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
 			/* can only do this if no one else is reading the log at the moment */
 			if ( !sl->sl_playing ) {
-				tavl_free( sl->sl_entries, (AVL_FREE)ch_free );
+				syncprov_free_slog( sl->sl_entries );
 				sl->sl_num = 0;
 				sl->sl_entries = NULL;
 			}
@@ -1699,15 +1717,14 @@ syncprov_add_slog( Operation *op )
 				BER_BVZERO( &sl->sl_mincsn[1] );
 			}
 		}
-		rc = tavl_insert( &sl->sl_entries, se, syncprov_sessionlog_cmp, syncprov_sessionlog_dup );
-		assert( rc == LDAP_SUCCESS );
+		kb_putp( slog, sl->sl_entries, (const slog_entry **)&se );
 		sl->sl_num++;
 		if ( !sl->sl_playing && sl->sl_num > sl->sl_size ) {
-			TAvlnode *edge = tavl_end( sl->sl_entries, TAVL_DIR_LEFT );
+			kbitr_t itr;
+			kb_itr_first( slog, sl->sl_entries, &itr );
 			while ( sl->sl_num > sl->sl_size ) {
 				int i;
-				TAvlnode *next = tavl_next( edge, TAVL_DIR_RIGHT );
-				se = edge->avl_data;
+				se = kb_itr_key( slog_entry *, &itr );
 				Debug( LDAP_DEBUG_SYNC, "%s syncprov_add_slog: "
 					"expiring csn=%s from sessionlog (sessionlog size=%d)\n",
 					op->o_log_prefix, se->se_csn.bv_val, sl->sl_num );
@@ -1726,9 +1743,9 @@ syncprov_add_slog( Operation *op )
 						op->o_log_prefix, se->se_sid, sl->sl_mincsn[i].bv_val, se->se_csn.bv_val );
 					ber_bvreplace( &sl->sl_mincsn[i], &se->se_csn );
 				}
-				tavl_delete( &sl->sl_entries, se, syncprov_sessionlog_cmp );
+				kb_itr_next( slog, sl->sl_entries, &itr );
+				kb_delp( slog, sl->sl_entries, (const slog_entry **)&se );
 				ch_free( se );
-				edge = next;
 				sl->sl_num--;
 			}
 		}
@@ -1964,9 +1981,9 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
 	BerVarray uuids, csns;
 	struct berval uuid[2] = {}, csn[2] = {};
 	slog_entry *se;
-	TAvlnode *entry;
 	char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
 	struct berval delcsn[2];
+	kbitr_t itr;
 
 	ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
 	/* Are there any log entries, and is the consumer state
@@ -2021,21 +2038,28 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
 	 */
 	assert( sl->sl_entries );
 
-	/* Find first relevant log entry. If greater than mincsn, backtrack one entry */
+	/* Find first relevant log entry. If none, just start at beginning. */
 	{
-		slog_entry te = {0};
+		slog_entry **lo, **hi, te = {0};
 		te.se_csn = *mincsn;
-		entry = tavl_find3( sl->sl_entries, &te, syncprov_sessionlog_cmp, &ndel );
+		/* If an exact match is found, both lo and hi will
+		 * point to the same record, otherwise lo and hi
+		 * will straddle the desired value.
+		 */
+		kb_interval( slog, sl->sl_entries, &te, &lo, &hi );
+		if ( lo )
+			/* Odd note: kb_itr_get never returns exactly
+			 * the specified value, it seems to return a few
+			 * records prior, even when an exact match exists.
+			 */
+			kb_itr_get( slog, sl->sl_entries, (const slog_entry **)lo, &itr );
+		else
+			kb_itr_first( slog, sl->sl_entries, &itr );
 	}
-	if ( ndel > 0 && entry )
-		entry = tavl_next( entry, TAVL_DIR_LEFT );
-	/* if none, just start at beginning */
-	if ( !entry )
-		entry = tavl_end( sl->sl_entries, TAVL_DIR_LEFT );
 
 	do {
 		char uuidstr[40] = {};
-		slog_entry *se = entry->avl_data;
+		slog_entry *se = kb_itr_key( slog_entry*, &itr );
 		int k;
 
 		/* Make sure writes can still make progress */
@@ -2095,7 +2119,7 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
 				uuidstr, csns[j].bv_val );
 		}
 		ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
-	} while ( (entry = tavl_next( entry, TAVL_DIR_RIGHT )) != NULL );
+	} while ( kb_itr_next( slog, sl->sl_entries, &itr ));
 	ldap_pvt_thread_rdwr_runlock( &sl->sl_mutex );
 	ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
 	sl->sl_playing--;
@@ -3680,6 +3704,7 @@ sp_cf_gen(ConfigArgs *c)
 			if ( !size ) break;
 			sl = ch_calloc( 1, sizeof( sessionlog ));
 			ldap_pvt_thread_rdwr_init( &sl->sl_mutex );
+			sl->sl_entries = kb_init( slog, SLOG_BTSIZE );
 			si->si_logs = sl;
 		}
 		sl->sl_size = size;
@@ -4019,7 +4044,7 @@ syncprov_db_destroy(
 		if ( si->si_logs ) {
 			sessionlog *sl = si->si_logs;
 
-			tavl_free( sl->sl_entries, (AVL_FREE)ch_free );
+			syncprov_free_slog( sl->sl_entries );
 			if ( sl->sl_mincsn )
 				ber_bvarray_free( sl->sl_mincsn );
 			if ( sl->sl_sids )