diff --git a/include/proto/proto_http.h b/include/proto/proto_http.h
index 477b9b0..a8056af 100644
--- a/include/proto/proto_http.h
+++ b/include/proto/proto_http.h
@@ -114,6 +114,7 @@
 			  struct hdr_idx *idx, int occ,
 			  struct hdr_ctx *ctx, char **vptr, int *vlen);
 
+struct http_txn *http_alloc_txn(struct stream *s);
 void http_init_txn(struct stream *s);
 void http_end_txn(struct stream *s);
 void http_reset_txn(struct stream *s);
diff --git a/include/types/proto_http.h b/include/types/proto_http.h
index b7dc4b5..d1fdf75 100644
--- a/include/types/proto_http.h
+++ b/include/types/proto_http.h
@@ -545,6 +545,8 @@
 
 extern const struct http_method_name http_known_methods[HTTP_METH_OTHER];
 
+extern struct pool_head *pool2_http_txn;
+
 #endif /* _TYPES_PROTO_HTTP_H */
 
 /*
diff --git a/include/types/stream.h b/include/types/stream.h
index 80d84ac..3a0a60f 100644
--- a/include/types/stream.h
+++ b/include/types/stream.h
@@ -124,7 +124,7 @@
 	struct server *srv_conn;        /* stream already has a slot on a server and is not in queue */
 	struct pendconn *pend_pos;      /* if not NULL, points to the position in the pending queue */
 
-	struct http_txn txn;            /* current HTTP transaction being processed. Should become a list. */
+	struct http_txn *txn;           /* current HTTP transaction being processed. Should become a list. */
 
 	struct task *task;              /* the task associated with this stream */
 	struct list list;               /* position in global streams list */
diff --git a/src/backend.c b/src/backend.c
index 2c2a61e..a8cf644 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -300,7 +300,7 @@
 struct server *get_server_ph_post(struct stream *s)
 {
 	unsigned int hash = 0;
-	struct http_txn *txn  = &s->txn;
+	struct http_txn *txn  = s->txn;
 	struct channel  *req  = &s->req;
 	struct http_msg *msg  = &txn->req;
 	struct proxy    *px   = s->be;
@@ -378,7 +378,7 @@
 struct server *get_server_hh(struct stream *s)
 {
 	unsigned int hash = 0;
-	struct http_txn *txn  = &s->txn;
+	struct http_txn *txn  = s->txn;
 	struct proxy    *px   = s->be;
 	unsigned int     plen = px->hh_len;
 	unsigned long    len;
@@ -553,7 +553,7 @@
 	if (conn &&
 	    (conn->flags & CO_FL_CONNECTED) &&
 	    objt_server(conn->target) && __objt_server(conn->target)->proxy == s->be &&
-	    ((s->txn.flags & TX_PREFER_LAST) ||
+	    ((s->txn && s->txn->flags & TX_PREFER_LAST) ||
 	     ((s->be->options & PR_O_PREF_LAST) &&
 	      (!s->be->max_ka_queue ||
 	       server_has_room(__objt_server(conn->target)) ||
@@ -627,29 +627,29 @@
 
 			case BE_LB_HASH_URI:
 				/* URI hashing */
-				if (s->txn.req.msg_state < HTTP_MSG_BODY)
+				if (!s->txn || s->txn->req.msg_state < HTTP_MSG_BODY)
 					break;
 				srv = get_server_uh(s->be,
-						    b_ptr(s->req.buf, -http_uri_rewind(&s->txn.req)),
-						    s->txn.req.sl.rq.u_l);
+						    b_ptr(s->req.buf, -http_uri_rewind(&s->txn->req)),
+						    s->txn->req.sl.rq.u_l);
 				break;
 
 			case BE_LB_HASH_PRM:
 				/* URL Parameter hashing */
-				if (s->txn.req.msg_state < HTTP_MSG_BODY)
+				if (!s->txn || s->txn->req.msg_state < HTTP_MSG_BODY)
 					break;
 
 				srv = get_server_ph(s->be,
-						    b_ptr(s->req.buf, -http_uri_rewind(&s->txn.req)),
-						    s->txn.req.sl.rq.u_l);
+						    b_ptr(s->req.buf, -http_uri_rewind(&s->txn->req)),
+						    s->txn->req.sl.rq.u_l);
 
-				if (!srv && s->txn.meth == HTTP_METH_POST)
+				if (!srv && s->txn->meth == HTTP_METH_POST)
 					srv = get_server_ph_post(s);
 				break;
 
 			case BE_LB_HASH_HDR:
 				/* Header Parameter hashing */
-				if (s->txn.req.msg_state < HTTP_MSG_BODY)
+				if (!s->txn || s->txn->req.msg_state < HTTP_MSG_BODY)
 					break;
 				srv = get_server_hh(s);
 				break;
@@ -861,9 +861,9 @@
 			 */
 
 			if (prev_srv != objt_server(s->target)) {
-				if ((s->txn.flags & TX_CK_MASK) == TX_CK_VALID) {
-					s->txn.flags &= ~TX_CK_MASK;
-					s->txn.flags |= TX_CK_DOWN;
+				if (s->txn && (s->txn->flags & TX_CK_MASK) == TX_CK_VALID) {
+					s->txn->flags &= ~TX_CK_MASK;
+					s->txn->flags |= TX_CK_DOWN;
 				}
 				s->flags |= SF_REDISP;
 				prev_srv->counters.redispatches++;
@@ -973,7 +973,7 @@
 			memset(&srv_conn->addr.from, 0, sizeof(srv_conn->addr.from));
 		break;
 	case CO_SRC_TPROXY_DYN:
-		if (src->bind_hdr_occ) {
+		if (src->bind_hdr_occ && s->txn) {
 			char *vptr;
 			int vlen;
 			int rewind;
@@ -983,9 +983,9 @@
 			((struct sockaddr_in *)&srv_conn->addr.from)->sin_port = 0;
 			((struct sockaddr_in *)&srv_conn->addr.from)->sin_addr.s_addr = 0;
 
-			b_rew(s->req.buf, rewind = http_hdr_rewind(&s->txn.req));
-			if (http_get_hdr(&s->txn.req, src->bind_hdr_name, src->bind_hdr_len,
-					 &s->txn.hdr_idx, src->bind_hdr_occ, NULL, &vptr, &vlen)) {
+			b_rew(s->req.buf, rewind = http_hdr_rewind(&s->txn->req));
+			if (http_get_hdr(&s->txn->req, src->bind_hdr_name, src->bind_hdr_len,
+					 &s->txn->hdr_idx, src->bind_hdr_occ, NULL, &vptr, &vlen)) {
 				((struct sockaddr_in *)&srv_conn->addr.from)->sin_addr.s_addr =
 					htonl(inetaddr_host_lim(vptr, vptr + vlen));
 			}
diff --git a/src/compression.c b/src/compression.c
index 0ae634f..50d41c1 100644
--- a/src/compression.c
+++ b/src/compression.c
@@ -184,7 +184,7 @@
  */
 int http_compression_buffer_add_data(struct stream *s, struct buffer *in, struct buffer *out)
 {
-	struct http_msg *msg = &s->txn.rsp;
+	struct http_msg *msg = &s->txn->rsp;
 	int consumed_data = 0;
 	int data_process_len;
 	int block1, block2;
@@ -234,7 +234,7 @@
 {
 	int to_forward;
 	int left;
-	struct http_msg *msg = &s->txn.rsp;
+	struct http_msg *msg = &s->txn->rsp;
 	struct buffer *ib = *in, *ob = *out;
 	char *tail;
 
diff --git a/src/dumpstats.c b/src/dumpstats.c
index 2aed81a..c24f815 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -4422,13 +4422,13 @@
 	int reql;
 
 	temp = get_trash_chunk();
-	if (temp->size < s->txn.req.body_len) {
+	if (temp->size < s->txn->req.body_len) {
 		/* too large request */
 		appctx->ctx.stats.st_code = STAT_STATUS_EXCD;
 		goto out;
 	}
 
-	reql = bo_getblk(si_oc(si), temp->str, s->txn.req.body_len, s->txn.req.eoh + 2);
+	reql = bo_getblk(si_oc(si), temp->str, s->txn->req.body_len, s->txn->req.eoh + 2);
 	if (reql <= 0) {
 		/* we need more data */
 		appctx->ctx.stats.st_code = STAT_STATUS_NONE;
@@ -4742,7 +4742,7 @@
 	else
 		chunk_appendf(&trash, "\r\n");
 
-	s->txn.status = 200;
+	s->txn->status = 200;
 	s->logs.tv_request = now;
 
 	if (bi_putchk(si_ic(si), &trash) == -1) {
@@ -4789,7 +4789,7 @@
 		     (appctx->ctx.stats.flags & STAT_NO_REFRESH) ? ";norefresh" : "",
 		     scope_txt);
 
-	s->txn.status = 303;
+	s->txn->status = 303;
 	s->logs.tv_request = now;
 
 	if (bi_putchk(si_ic(si), &trash) == -1) {
@@ -4822,7 +4822,7 @@
 	/* all states are processed in sequence */
 	if (appctx->st0 == STAT_HTTP_HEAD) {
 		if (stats_send_http_headers(si)) {
-			if (s->txn.meth == HTTP_METH_HEAD)
+			if (s->txn->meth == HTTP_METH_HEAD)
 				appctx->st0 = STAT_HTTP_DONE;
 			else
 				appctx->st0 = STAT_HTTP_DUMP;
@@ -5134,10 +5134,11 @@
 			     " age=%s)\n",
 			     human_time(now.tv_sec - sess->logs.accept_date.tv_sec, 1));
 
-		chunk_appendf(&trash,
+		if (sess->txn)
+			chunk_appendf(&trash,
 			     "  txn=%p flags=0x%x meth=%d status=%d req.st=%s rsp.st=%s waiting=%d\n",
-			     &sess->txn, sess->txn.flags, sess->txn.meth, sess->txn.status,
-			      http_msg_state_str(sess->txn.req.msg_state), http_msg_state_str(sess->txn.rsp.msg_state), !LIST_ISEMPTY(&sess->buffer_wait));
+			      sess->txn, sess->txn->flags, sess->txn->meth, sess->txn->status,
+			      http_msg_state_str(sess->txn->req.msg_state), http_msg_state_str(sess->txn->rsp.msg_state), !LIST_ISEMPTY(&sess->buffer_wait));
 
 		chunk_appendf(&trash,
 			     "  si[0]=%p (state=%s flags=0x%02x endp0=%s:%p exp=%s, et=0x%03x)\n",
@@ -5247,7 +5248,7 @@
 			     sess->req.buf,
 			     sess->req.buf->data, sess->req.buf->o,
 			     (int)(sess->req.buf->p - sess->req.buf->data),
-			     sess->txn.req.next, sess->req.buf->i,
+			     sess->txn ? sess->txn->req.next : 0, sess->req.buf->i,
 			     sess->req.buf->size);
 
 		chunk_appendf(&trash,
@@ -5276,7 +5277,7 @@
 			     sess->res.buf,
 			     sess->res.buf->data, sess->res.buf->o,
 			     (int)(sess->res.buf->p - sess->res.buf->data),
-			     sess->txn.rsp.next, sess->res.buf->i,
+			     sess->txn ? sess->txn->rsp.next : 0, sess->res.buf->i,
 			     sess->res.buf->size);
 
 		if (bi_putchk(si_ic(si), &trash) == -1) {
diff --git a/src/frontend.c b/src/frontend.c
index 3a71bc4..3a28d6f 100644
--- a/src/frontend.c
+++ b/src/frontend.c
@@ -127,9 +127,7 @@
 		 * that we may make use of them. This of course includes
 		 * (mode == PR_MODE_HTTP).
 		 */
-		s->txn.hdr_idx.size = global.tune.max_http_hdr;
-
-		if (unlikely((s->txn.hdr_idx.v = pool_alloc2(pool2_hdr_idx)) == NULL))
+		if (unlikely(!http_alloc_txn(s)))
 			goto out_free_rspcap; /* no memory */
 
 		/* and now initialize the HTTP transaction state */
diff --git a/src/hlua.c b/src/hlua.c
index e54c029..43d9c1b 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -2169,13 +2169,7 @@
 	socket->s->res_cap = NULL;
 
 	/* XXX: See later. */
-	socket->s->txn.sessid = NULL;
-	socket->s->txn.srv_cookie = NULL;
-	socket->s->txn.cli_cookie = NULL;
-	socket->s->txn.uri = NULL;
-	socket->s->txn.hdr_idx.v = NULL;
-	socket->s->txn.hdr_idx.size = 0;
-	socket->s->txn.hdr_idx.used = 0;
+	socket->s->txn = NULL;
 
 	/* Configure "left" stream interface as applet. This "si" produce
 	 * and use the data received from the server. The applet is initialized
@@ -2971,17 +2965,20 @@
 	/* Create the table. */
 	lua_newtable(L);
 
+	if (!htxn->s->txn)
+		return 1;
+
 	/* Build array of headers. */
 	old_idx = 0;
-	cur_next = msg->chn->buf->p + hdr_idx_first_pos(&htxn->s->txn.hdr_idx);
+	cur_next = msg->chn->buf->p + hdr_idx_first_pos(&htxn->s->txn->hdr_idx);
 
 	while (1) {
-		cur_idx = htxn->s->txn.hdr_idx.v[old_idx].next;
+		cur_idx = htxn->s->txn->hdr_idx.v[old_idx].next;
 		if (!cur_idx)
 			break;
 		old_idx = cur_idx;
 
-		cur_hdr  = &htxn->s->txn.hdr_idx.v[cur_idx];
+		cur_hdr  = &htxn->s->txn->hdr_idx.v[cur_idx];
 		cur_ptr  = cur_next;
 		cur_next = cur_ptr + cur_hdr->len + cur_hdr->cr + 1;
 
@@ -3021,7 +3018,7 @@
 	MAY_LJMP(check_args(L, 1, "req_get_headers"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_get_headers(L, htxn, &htxn->s->txn.req);
+	return hlua_http_get_headers(L, htxn, &htxn->s->txn->req);
 }
 
 __LJMP static int hlua_http_res_get_headers(lua_State *L)
@@ -3031,7 +3028,7 @@
 	MAY_LJMP(check_args(L, 1, "res_get_headers"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_get_headers(L, htxn, &htxn->s->txn.rsp);
+	return hlua_http_get_headers(L, htxn, &htxn->s->txn->rsp);
 }
 
 /* This function replace full header, or just a value in
@@ -3062,7 +3059,7 @@
 	MAY_LJMP(check_args(L, 4, "req_rep_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn.req, HTTP_REQ_ACT_REPLACE_HDR));
+	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn->req, HTTP_REQ_ACT_REPLACE_HDR));
 }
 
 __LJMP static int hlua_http_res_rep_hdr(lua_State *L)
@@ -3072,7 +3069,7 @@
 	MAY_LJMP(check_args(L, 4, "res_rep_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn.rsp, HTTP_RES_ACT_REPLACE_HDR));
+	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn->rsp, HTTP_RES_ACT_REPLACE_HDR));
 }
 
 __LJMP static int hlua_http_req_rep_val(lua_State *L)
@@ -3082,7 +3079,7 @@
 	MAY_LJMP(check_args(L, 4, "req_rep_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn.req, HTTP_REQ_ACT_REPLACE_VAL));
+	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn->req, HTTP_REQ_ACT_REPLACE_VAL));
 }
 
 __LJMP static int hlua_http_res_rep_val(lua_State *L)
@@ -3092,7 +3089,7 @@
 	MAY_LJMP(check_args(L, 4, "res_rep_val"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn.rsp, HTTP_RES_ACT_REPLACE_VAL));
+	return MAY_LJMP(hlua_http_rep_hdr(L, htxn, &htxn->s->txn->rsp, HTTP_RES_ACT_REPLACE_VAL));
 }
 
 /* This function deletes all the occurences of an header.
@@ -3103,7 +3100,7 @@
 	size_t len;
 	const char *name = MAY_LJMP(luaL_checklstring(L, 2, &len));
 	struct hdr_ctx ctx;
-	struct http_txn *txn = &htxn->s->txn;
+	struct http_txn *txn = htxn->s->txn;
 
 	ctx.idx = 0;
 	while (http_find_header2(name, len, msg->chn->buf->p, &txn->hdr_idx, &ctx))
@@ -3118,7 +3115,7 @@
 	MAY_LJMP(check_args(L, 2, "req_del_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_del_hdr(L, htxn, &htxn->s->txn.req);
+	return hlua_http_del_hdr(L, htxn, &htxn->s->txn->req);
 }
 
 __LJMP static int hlua_http_res_del_hdr(lua_State *L)
@@ -3128,7 +3125,7 @@
 	MAY_LJMP(check_args(L, 2, "req_del_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_del_hdr(L, htxn, &htxn->s->txn.rsp);
+	return hlua_http_del_hdr(L, htxn, &htxn->s->txn->rsp);
 }
 
 /* This function adds an header. It is a wrapper used by
@@ -3157,7 +3154,7 @@
 	p++;
 	memcpy(p, value, value_len);
 
-	lua_pushboolean(L, http_header_add_tail2(msg, &htxn->s->txn.hdr_idx,
+	lua_pushboolean(L, http_header_add_tail2(msg, &htxn->s->txn->hdr_idx,
 	                                         trash.str, trash.len) != 0);
 
 	return 0;
@@ -3170,7 +3167,7 @@
 	MAY_LJMP(check_args(L, 3, "req_add_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_add_hdr(L, htxn, &htxn->s->txn.req);
+	return hlua_http_add_hdr(L, htxn, &htxn->s->txn->req);
 }
 
 __LJMP static int hlua_http_res_add_hdr(lua_State *L)
@@ -3180,7 +3177,7 @@
 	MAY_LJMP(check_args(L, 3, "res_add_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	return hlua_http_add_hdr(L, htxn, &htxn->s->txn.rsp);
+	return hlua_http_add_hdr(L, htxn, &htxn->s->txn->rsp);
 }
 
 static int hlua_http_req_set_hdr(lua_State *L)
@@ -3190,8 +3187,8 @@
 	MAY_LJMP(check_args(L, 3, "req_set_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	hlua_http_del_hdr(L, htxn, &htxn->s->txn.req);
-	return hlua_http_add_hdr(L, htxn, &htxn->s->txn.req);
+	hlua_http_del_hdr(L, htxn, &htxn->s->txn->req);
+	return hlua_http_add_hdr(L, htxn, &htxn->s->txn->req);
 }
 
 static int hlua_http_res_set_hdr(lua_State *L)
@@ -3201,8 +3198,8 @@
 	MAY_LJMP(check_args(L, 3, "res_set_hdr"));
 	htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 
-	hlua_http_del_hdr(L, htxn, &htxn->s->txn.rsp);
-	return hlua_http_add_hdr(L, htxn, &htxn->s->txn.rsp);
+	hlua_http_del_hdr(L, htxn, &htxn->s->txn->rsp);
+	return hlua_http_add_hdr(L, htxn, &htxn->s->txn->rsp);
 }
 
 /* This function set the method. */
@@ -3211,7 +3208,7 @@
 	struct hlua_txn *htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 	size_t name_len;
 	const char *name = MAY_LJMP(luaL_checklstring(L, 2, &name_len));
-	struct http_txn *txn = &htxn->s->txn;
+	struct http_txn *txn = htxn->s->txn;
 
 	lua_pushboolean(L, http_replace_req_line(0, name, name_len, htxn->p, htxn->s, txn) != -1);
 	return 1;
@@ -3223,7 +3220,7 @@
 	struct hlua_txn *htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 	size_t name_len;
 	const char *name = MAY_LJMP(luaL_checklstring(L, 2, &name_len));
-	struct http_txn *txn = &htxn->s->txn;
+	struct http_txn *txn = htxn->s->txn;
 
 	lua_pushboolean(L, http_replace_req_line(1, name, name_len, htxn->p, htxn->s, txn) != -1);
 	return 1;
@@ -3235,7 +3232,7 @@
 	struct hlua_txn *htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 	size_t name_len;
 	const char *name = MAY_LJMP(luaL_checklstring(L, 2, &name_len));
-	struct http_txn *txn = &htxn->s->txn;
+	struct http_txn *txn = htxn->s->txn;
 
 	/* Check length. */
 	if (name_len > trash.size - 1) {
@@ -3259,7 +3256,7 @@
 	struct hlua_txn *htxn = MAY_LJMP(hlua_checkhttp(L, 1));
 	size_t name_len;
 	const char *name = MAY_LJMP(luaL_checklstring(L, 2, &name_len));
-	struct http_txn *txn = &htxn->s->txn;
+	struct http_txn *txn = htxn->s->txn;
 
 	lua_pushboolean(L, http_replace_req_line(3, name, name_len, htxn->p, htxn->s, txn) != -1);
 	return 1;
diff --git a/src/log.c b/src/log.c
index 949dc29..97a2080 100644
--- a/src/log.c
+++ b/src/log.c
@@ -922,7 +922,7 @@
 	struct session *sess = strm_sess(s);
 	struct proxy *fe = sess->fe;
 	struct proxy *be = s->be;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	char *uri;
 	struct tm tm;
 	int t_request;
@@ -1615,7 +1615,7 @@
               ((s->flags & SF_ERR_MASK) > SF_ERR_LOCAL) ||
 	      (((s->flags & SF_ERR_MASK) == SF_ERR_NONE) &&
 	       (s->si[1].conn_retries != s->be->conn_retries)) ||
-	      ((sess->fe->mode == PR_MODE_HTTP) && s->txn.status >= 500);
+	      ((sess->fe->mode == PR_MODE_HTTP) && s->txn && s->txn->status >= 500);
 
 	if (!err && (sess->fe->options2 & PR_O2_NOLOGNORM))
 		return;
diff --git a/src/peers.c b/src/peers.c
index 08ccfa9..b5d1d8e 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -1113,7 +1113,6 @@
 	struct proxy *p = (struct proxy *)l->frontend; /* attached frontend */
 	struct appctx *appctx;
 	struct stream *s;
-	struct http_txn *txn;
 	struct task *t;
 	struct connection *conn;
 
@@ -1218,17 +1217,7 @@
 	s->uniq_id = 0;
 	s->unique_id = NULL;
 
-	txn = &s->txn;
-	/* Those variables will be checked and freed if non-NULL in
-	 * stream.c:stream_free(). It is important that they are
-	 * properly initialized.
-	 */
-	txn->sessid = NULL;
-	txn->srv_cookie = NULL;
-	txn->cli_cookie = NULL;
-	txn->uri = NULL;
-	txn->hdr_idx.v = NULL;
-	txn->hdr_idx.size = txn->hdr_idx.used = 0;
+	s->txn = NULL;
 
 	channel_init(&s->req);
 	s->req.flags |= CF_READ_ATTACHED; /* the producer is already connected */
diff --git a/src/proto_http.c b/src/proto_http.c
index 8bd6b5e..9b68270 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -834,7 +834,7 @@
 	channel_auto_close(si_ic(si));
 	channel_auto_read(si_ic(si));
 	if (status > 0 && msg) {
-		s->txn.status = status;
+		s->txn->status = status;
 		bo_inject(si_ic(si), msg->str, msg->len);
 	}
 	if (!(s->flags & SF_ERR_MASK))
@@ -1001,7 +1001,7 @@
 	/* 3: add the request URI. Since it was already forwarded, we need
 	 * to temporarily rewind the buffer.
 	 */
-	txn = &s->txn;
+	txn = s->txn;
 	b_rew(s->req.buf, rewind = http_hdr_rewind(&txn->req));
 
 	path = http_get_path(txn);
@@ -1060,7 +1060,7 @@
 				  503, http_error_message(s, HTTP_ERR_503));
 	else if (err_type & SI_ET_CONN_ABRT)
 		http_server_error(s, si, SF_ERR_CLICL, SF_FINST_C,
-				  503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+				  503, (s->txn->flags & TX_NOT_FIRST) ? NULL :
 				  http_error_message(s, HTTP_ERR_503));
 	else if (err_type & SI_ET_QUEUE_TO)
 		http_server_error(s, si, SF_ERR_SRVTO, SF_FINST_Q,
@@ -1070,7 +1070,7 @@
 				  503, http_error_message(s, HTTP_ERR_503));
 	else if (err_type & SI_ET_CONN_TO)
 		http_server_error(s, si, SF_ERR_SRVTO, SF_FINST_C,
-				  503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+				  503, (s->txn->flags & TX_NOT_FIRST) ? NULL :
 				  http_error_message(s, HTTP_ERR_503));
 	else if (err_type & SI_ET_CONN_ERR)
 		http_server_error(s, si, SF_ERR_SRVCL, SF_FINST_C,
@@ -1078,7 +1078,7 @@
 				  http_error_message(s, HTTP_ERR_503));
 	else if (err_type & SI_ET_CONN_RES)
 		http_server_error(s, si, SF_ERR_RESOURCE, SF_FINST_C,
-				  503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+				  503, (s->txn->flags & TX_NOT_FIRST) ? NULL :
 				  http_error_message(s, HTTP_ERR_503));
 	else /* SI_ET_CONN_OTHER and others */
 		http_server_error(s, si, SF_ERR_INTERNAL, SF_FINST_C,
@@ -1437,7 +1437,7 @@
 get_http_auth(struct stream *s)
 {
 
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct chunk auth_method;
 	struct hdr_ctx ctx;
 	char *h, *p;
@@ -2240,7 +2240,7 @@
  */
 int select_compression_request_header(struct stream *s, struct buffer *req)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->req;
 	struct hdr_ctx ctx;
 	struct comp_algo *comp_algo = NULL;
@@ -2351,7 +2351,7 @@
  */
 int select_compression_response_header(struct stream *s, struct buffer *res)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->rsp;
 	struct hdr_ctx ctx;
 	struct comp_type *comp_type;
@@ -2550,7 +2550,7 @@
 	int cur_idx;
 	int use_close_only;
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->req;
 	struct hdr_ctx ctx;
 
@@ -3103,7 +3103,7 @@
 {
 	struct stats_admin_rule *stats_admin_rule;
 	struct stream_interface *si = &s->si[1];
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->req;
 	struct uri_auth *uri_auth = s->be->uri_auth;
 	const char *uri, *h, *lookup;
@@ -3114,7 +3114,7 @@
 	appctx->st1 = appctx->st2 = 0;
 	appctx->ctx.stats.st_code = STAT_STATUS_INIT;
 	appctx->ctx.stats.flags |= STAT_FMT_HTML; /* assume HTML mode by default */
-	if ((msg->flags & HTTP_MSGF_VER_11) && (s->txn.meth != HTTP_METH_HEAD))
+	if ((msg->flags & HTTP_MSGF_VER_11) && (s->txn->meth != HTTP_METH_HEAD))
 		appctx->ctx.stats.flags |= STAT_CHUNKED;
 
 	uri = msg->chn->buf->p + msg->sl.rq.u;
@@ -3197,7 +3197,7 @@
 		int ret = 1;
 
 		if (stats_admin_rule->cond) {
-			ret = acl_exec_cond(stats_admin_rule->cond, s->be, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
+			ret = acl_exec_cond(stats_admin_rule->cond, s->be, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
 			ret = acl_pass(ret);
 			if (stats_admin_rule->cond->pol == ACL_COND_UNLESS)
 				ret = !ret;
@@ -3258,7 +3258,7 @@
 {
 	struct hdr_ctx ctx;
 	char *buf = msg->chn->buf->p;
-	struct hdr_idx *idx = &s->txn.hdr_idx;
+	struct hdr_idx *idx = &s->txn->hdr_idx;
 	int (*http_find_hdr_func)(const char *name, int len, char *sol,
 	                          struct hdr_idx *idx, struct hdr_ctx *ctx);
 	struct chunk *output = get_trash_chunk();
@@ -3565,7 +3565,7 @@
 				void *ptr;
 
 				t = rule->act_prm.trk_ctr.table.t;
-				key = stktable_fetch_key(t, s->be, s, &s->txn, SMP_OPT_DIR_REQ | SMP_OPT_FINAL, rule->act_prm.trk_ctr.expr, NULL);
+				key = stktable_fetch_key(t, s->be, s, s->txn, SMP_OPT_DIR_REQ | SMP_OPT_FINAL, rule->act_prm.trk_ctr.expr, NULL);
 
 				if (key && (ts = stktable_get_entry(t, key))) {
 					stream_track_stkctr(&s->stkctr[http_req_trk_idx(rule->action)], t, ts);
@@ -4073,7 +4073,7 @@
 int http_process_req_common(struct stream *s, struct channel *req, int an_bit, struct proxy *px)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->req;
 	struct redirect_rule *rule;
 	struct cond_wordlist *wl;
@@ -4314,7 +4314,7 @@
 int http_process_request(struct stream *s, struct channel *req, int an_bit)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->req;
 	struct connection *cli_conn = objt_conn(s->si[1].end);
 
@@ -4592,7 +4592,7 @@
 	 * that parameter. This will be done in another analyser.
 	 */
 	if (!(s->flags & (SF_ASSIGNED|SF_DIRECT)) &&
-	    s->txn.meth == HTTP_METH_POST && s->be->url_param_name != NULL &&
+	    s->txn->meth == HTTP_METH_POST && s->be->url_param_name != NULL &&
 	    (msg->flags & (HTTP_MSGF_CNT_LEN|HTTP_MSGF_TE_CHNK))) {
 		channel_dont_connect(req);
 		req->analysers |= AN_REQ_HTTP_BODY;
@@ -4661,7 +4661,7 @@
  */
 int http_process_tarpit(struct stream *s, struct channel *req, int an_bit)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 
 	/* This connection is being tarpitted. The CLIENT side has
 	 * already set the connect expiration date to the right
@@ -4707,8 +4707,8 @@
 int http_wait_for_request_body(struct stream *s, struct channel *req, int an_bit)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
-	struct http_msg *msg = &s->txn.req;
+	struct http_txn *txn = s->txn;
+	struct http_msg *msg = &s->txn->req;
 
 	/* We have to parse the HTTP request body to find any required data.
 	 * "balance url_param check_post" should have been the only way to get
@@ -4903,7 +4903,7 @@
  */
 void http_end_txn_clean_session(struct stream *s)
 {
-	int prev_status = s->txn.status;
+	int prev_status = s->txn->status;
 	struct proxy *fe = strm_sess(s)->fe;
 
 	/* FIXME: We need a more portable way of releasing a backend's and a
@@ -4915,7 +4915,7 @@
 	/* unless we're doing keep-alive, we want to quickly close the connection
 	 * to the server.
 	 */
-	if (((s->txn.flags & TX_CON_WANT_MSK) != TX_CON_WANT_KAL) ||
+	if (((s->txn->flags & TX_CON_WANT_MSK) != TX_CON_WANT_KAL) ||
 	    !si_conn_ready(&s->si[1])) {
 		s->si[1].flags |= SI_FL_NOLINGER | SI_FL_NOHALF;
 		si_shutr(&s->si[1]);
@@ -4931,10 +4931,10 @@
 	s->logs.t_close = tv_ms_elapsed(&s->logs.tv_accept, &now);
 	stream_process_counters(s);
 
-	if (s->txn.status) {
+	if (s->txn->status) {
 		int n;
 
-		n = s->txn.status / 100;
+		n = s->txn->status / 100;
 		if (n < 1 || n > 5)
 			n = 0;
 
@@ -4997,7 +4997,7 @@
 	/* only release our endpoint if we don't intend to reuse the
 	 * connection.
 	 */
-	if (((s->txn.flags & TX_CON_WANT_MSK) != TX_CON_WANT_KAL) ||
+	if (((s->txn->flags & TX_CON_WANT_MSK) != TX_CON_WANT_KAL) ||
 	    !si_conn_ready(&s->si[1])) {
 		si_release_endpoint(&s->si[1]);
 	}
@@ -5013,9 +5013,9 @@
 	s->flags &= ~(SF_CURR_SESS|SF_REDIRECTABLE|SF_SRV_REUSED);
 	s->flags &= ~(SF_ERR_MASK|SF_FINST_MASK|SF_REDISP);
 
-	s->txn.meth = 0;
+	s->txn->meth = 0;
 	http_reset_txn(s);
-	s->txn.flags |= TX_NOT_FIRST | TX_WAIT_NEXT_RQ;
+	s->txn->flags |= TX_NOT_FIRST | TX_WAIT_NEXT_RQ;
 
 	if (prev_status == 401 || prev_status == 407) {
 		/* In HTTP keep-alive mode, if we receive a 401, we still have
@@ -5025,7 +5025,7 @@
 		 * an opportunity for sending the challenge to the proper place,
 		 * it's better to do it (at least it helps with debugging).
 		 */
-		s->txn.flags |= TX_PREFER_LAST;
+		s->txn->flags |= TX_PREFER_LAST;
 	}
 
 	if (fe->options2 & PR_O2_INDEPSTR)
@@ -5074,7 +5074,7 @@
 int http_sync_req_state(struct stream *s)
 {
 	struct channel *chn = &s->req;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	unsigned int old_flags = chn->flags;
 	unsigned int old_state = txn->req.msg_state;
 
@@ -5212,7 +5212,7 @@
 int http_sync_res_state(struct stream *s)
 {
 	struct channel *chn = &s->res;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	unsigned int old_flags = chn->flags;
 	unsigned int old_state = txn->rsp.msg_state;
 
@@ -5340,7 +5340,7 @@
  */
 int http_resync_states(struct stream *s)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	int old_req_state = txn->req.msg_state;
 	int old_res_state = txn->rsp.msg_state;
 
@@ -5417,8 +5417,8 @@
 int http_request_forward_body(struct stream *s, struct channel *req, int an_bit)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
-	struct http_msg *msg = &s->txn.req;
+	struct http_txn *txn = s->txn;
+	struct http_msg *msg = &s->txn->req;
 
 	if (unlikely(msg->msg_state < HTTP_MSG_BODY))
 		return 0;
@@ -5589,7 +5589,7 @@
 				channel_auto_read(req);
 				channel_auto_close(req);
 			}
-			else if (s->txn.meth == HTTP_METH_POST) {
+			else if (s->txn->meth == HTTP_METH_POST) {
 				/* POST requests may require to read extra CRLF
 				 * sent by broken browsers and which could cause
 				 * an RST to be sent upon close on some systems
@@ -5722,7 +5722,7 @@
 int http_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->rsp;
 	struct hdr_ctx ctx;
 	int use_close_only;
@@ -6290,7 +6290,7 @@
 int http_process_res_common(struct stream *s, struct channel *rep, int an_bit, struct proxy *px)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct http_msg *msg = &txn->rsp;
 	struct proxy *cur_proxy;
 	struct cond_wordlist *wl;
@@ -6630,8 +6630,8 @@
 int http_response_forward_body(struct stream *s, struct channel *res, int an_bit)
 {
 	struct session *sess = s->sess;
-	struct http_txn *txn = &s->txn;
-	struct http_msg *msg = &s->txn.rsp;
+	struct http_txn *txn = s->txn;
+	struct http_msg *msg = &s->txn->rsp;
 	static struct buffer *tmpbuf = &buf_empty;
 	int compressing = 0;
 	int ret;
@@ -6947,7 +6947,7 @@
 {
 	char *cur_ptr, *cur_end, *cur_next;
 	int cur_idx, old_idx, last_hdr;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct hdr_idx_elem *cur_hdr;
 	int delta;
 
@@ -7059,7 +7059,7 @@
 {
 	char *cur_ptr, *cur_end;
 	int done;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	int delta;
 
 	if (unlikely(txn->flags & (TX_CLDENY | TX_CLTARPIT)))
@@ -7151,7 +7151,7 @@
  */
 int apply_filters_to_request(struct stream *s, struct channel *req, struct proxy *px)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct hdr_exp *exp;
 
 	for (exp = px->req_exp; exp; exp = exp->next) {
@@ -7207,7 +7207,7 @@
  * If the server is found, it's assigned to the stream.
  */
 void manage_client_side_appsession(struct stream *s, const char *buf, int len) {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	appsess *asession = NULL;
 	char *sessid_temp = NULL;
 
@@ -7359,7 +7359,7 @@
  */
 void manage_client_side_cookies(struct stream *s, struct channel *req)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct session *sess = s->sess;
 	int preserve_hdr;
 	int cur_idx, old_idx;
@@ -7811,7 +7811,7 @@
 {
 	char *cur_ptr, *cur_end, *cur_next;
 	int cur_idx, old_idx, last_hdr;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct hdr_idx_elem *cur_hdr;
 	int delta;
 
@@ -7902,7 +7902,7 @@
 {
 	char *cur_ptr, *cur_end;
 	int done;
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	int delta;
 
 
@@ -7975,7 +7975,7 @@
  */
 int apply_filters_to_response(struct stream *s, struct channel *rtr, struct proxy *px)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct hdr_exp *exp;
 
 	for (exp = px->rsp_exp; exp; exp = exp->next) {
@@ -8033,7 +8033,7 @@
  */
 void manage_server_side_cookies(struct stream *s, struct channel *res)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct session *sess = s->sess;
 	struct server *srv;
 	int is_cookie2;
@@ -8397,7 +8397,7 @@
  */
 void check_response_for_cacheability(struct stream *s, struct channel *rtr)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	char *p1, *p2;
 
 	char *cur_ptr, *cur_end, *cur_next;
@@ -8493,7 +8493,7 @@
 	int mode = s->be->options2 & PR_O2_AS_M_ANY;
 
 	if (s->be->appsession_name == NULL ||
-	    (s->txn.meth != HTTP_METH_GET && s->txn.meth != HTTP_METH_POST && s->txn.meth != HTTP_METH_HEAD)) {
+	    (s->txn->meth != HTTP_METH_GET && s->txn->meth != HTTP_METH_POST && s->txn->meth != HTTP_METH_HEAD)) {
 		return;
 	}
 
@@ -8625,7 +8625,7 @@
 	es->ev_id = error_snapshot_id++;
 	es->b_flags = chn->flags;
 	es->s_flags = s->flags;
-	es->t_flags = s->txn.flags;
+	es->t_flags = s->txn->flags;
 	es->m_flags = msg->flags;
 	es->b_out = chn->buf->o;
 	es->b_wrap = chn->buf->data + chn->buf->size - chn->buf->p;
@@ -8789,6 +8789,34 @@
 	shut_your_big_mouth_gcc(write(1, trash.str, trash.len));
 }
 
+
+/* Allocate a new HTTP transaction for stream <s> unless there is one already.
+ * The hdr_idx is allocated as well. In case of allocation failure, everything
+ * allocated is freed and NULL is returned. Otherwise the new transaction is
+ * assigned to the stream and returned.
+ */
+struct http_txn *http_alloc_txn(struct stream *s)
+{
+	struct http_txn *txn = s->txn;
+
+	if (txn)
+		return txn;
+
+	txn = pool_alloc2(pool2_http_txn);
+	if (!txn)
+		return txn;
+
+	txn->hdr_idx.size = global.tune.max_http_hdr;
+	txn->hdr_idx.v    = pool_alloc2(pool2_hdr_idx);
+	if (!txn->hdr_idx.v) {
+		pool_free2(pool2_http_txn, txn);
+		return NULL;
+	}
+
+	s->txn = txn;
+	return txn;
+}
+
 /*
  * Initialize a new HTTP transaction for stream <s>. It is assumed that all
  * the required fields are properly allocated and that we only need to (re)init
@@ -8796,7 +8824,7 @@
  */
 void http_init_txn(struct stream *s)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct proxy *fe = strm_sess(s)->fe;
 
 	txn->flags = 0;
@@ -8805,6 +8833,11 @@
 	txn->cookie_first_date = 0;
 	txn->cookie_last_date = 0;
 
+	txn->sessid = NULL;
+	txn->srv_cookie = NULL;
+	txn->cli_cookie = NULL;
+	txn->uri = NULL;
+
 	txn->req.flags = 0;
 	txn->req.sol = txn->req.eol = txn->req.eoh = 0; /* relative to the buffer */
 	txn->req.next = 0;
@@ -8833,7 +8866,7 @@
 /* to be used at the end of a transaction */
 void http_end_txn(struct stream *s)
 {
-	struct http_txn *txn = &s->txn;
+	struct http_txn *txn = s->txn;
 	struct proxy *fe = strm_sess(s)->fe;
 
 	/* release any possible compression context */
@@ -9876,8 +9909,10 @@
 	struct http_txn *txn = l7;
 	struct http_msg *msg = &txn->req;
 
-	/* Note: hdr_idx.v cannot be NULL in this ACL because the ACL is tagged
-	 * as a layer7 ACL, which involves automatic allocation of hdr_idx.
+	/* Note: this function may only be used from places where
+	 * http_init_txn() has already been done, and implies that <s>,
+	 * <txn>, and <hdr_idx.v> are properly set. An extra check protects
+	 * against an eventual mistake in the fetch capability matrix.
 	 */
 
 	if (unlikely(!s || !txn))
@@ -10668,7 +10703,7 @@
                          const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
 	smp->type = SMP_T_BOOL;
-	smp->data.uint = !(s->txn.flags & TX_NOT_FIRST);
+	smp->data.uint = !(s->txn->flags & TX_NOT_FIRST);
 	return 1;
 }
 
@@ -10687,7 +10722,7 @@
 		return 0;
 
 	smp->type = SMP_T_BOOL;
-	smp->data.uint = check_user(args->data.usr, l4->txn.auth.user, l4->txn.auth.pass);
+	smp->data.uint = check_user(args->data.usr, l4->txn->auth.user, l4->txn->auth.pass);
 	return 1;
 }
 
@@ -10709,7 +10744,7 @@
 	 * report that it unconditionally does not match. Otherwise we return
 	 * a string containing the username.
 	 */
-	if (!check_user(args->data.usr, l4->txn.auth.user, l4->txn.auth.pass))
+	if (!check_user(args->data.usr, l4->txn->auth.user, l4->txn->auth.pass))
 		return 0;
 
 	/* pat_match_auth() will need the user list */
@@ -10717,8 +10752,8 @@
 
 	smp->type = SMP_T_STR;
 	smp->flags = SMP_F_CONST;
-	smp->data.str.str = l4->txn.auth.user;
-	smp->data.str.len = strlen(l4->txn.auth.user);
+	smp->data.str.str = l4->txn->auth.user;
+	smp->data.str.len = strlen(l4->txn->auth.user);
 
 	return 1;
 }
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index e77edc4..af61c54 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -1134,7 +1134,7 @@
 		enum acl_test_res ret = ACL_TEST_PASS;
 
 		if (rule->cond) {
-			ret = acl_exec_cond(rule->cond, s->be, s, &s->txn, SMP_OPT_DIR_REQ | partial);
+			ret = acl_exec_cond(rule->cond, s->be, s, s->txn, SMP_OPT_DIR_REQ | partial);
 			if (ret == ACL_TEST_MISS)
 				goto missing_data;
 
@@ -1175,7 +1175,7 @@
 					continue;
 
 				t = rule->act_prm.trk_ctr.table.t;
-				key = stktable_fetch_key(t, s->be, s, &s->txn, SMP_OPT_DIR_REQ | partial, rule->act_prm.trk_ctr.expr, &smp);
+				key = stktable_fetch_key(t, s->be, s, s->txn, SMP_OPT_DIR_REQ | partial, rule->act_prm.trk_ctr.expr, &smp);
 
 				if ((smp.flags & SMP_F_MAY_CHANGE) && !(partial & SMP_OPT_FINAL))
 					goto missing_data; /* key might appear later */
@@ -1193,7 +1193,7 @@
 				char **cap = s->req_cap;
 				int len;
 
-				key = sample_fetch_string(s->be, s, &s->txn, SMP_OPT_DIR_REQ | partial, rule->act_prm.cap.expr);
+				key = sample_fetch_string(s->be, s, s->txn, SMP_OPT_DIR_REQ | partial, rule->act_prm.cap.expr);
 				if (!key)
 					continue;
 
@@ -1292,7 +1292,7 @@
 		enum acl_test_res ret = ACL_TEST_PASS;
 
 		if (rule->cond) {
-			ret = acl_exec_cond(rule->cond, s->be, s, &s->txn, SMP_OPT_DIR_RES | partial);
+			ret = acl_exec_cond(rule->cond, s->be, s, s->txn, SMP_OPT_DIR_RES | partial);
 			if (ret == ACL_TEST_MISS) {
 				/* just set the analyser timeout once at the beginning of the response */
 				if (!tick_isset(rep->analyse_exp) && s->be->tcp_rep.inspect_delay)
@@ -1407,7 +1407,7 @@
 					continue;
 
 				t = rule->act_prm.trk_ctr.table.t;
-				key = stktable_fetch_key(t, s->be, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->act_prm.trk_ctr.expr, NULL);
+				key = stktable_fetch_key(t, s->be, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->act_prm.trk_ctr.expr, NULL);
 
 				if (key && (ts = stktable_get_entry(t, key)))
 					stream_track_stkctr(&s->stkctr[tcp_trk_idx(rule->action)], t, ts);
diff --git a/src/proxy.c b/src/proxy.c
index 9b23db0..f55aaa4 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -940,39 +940,40 @@
 	if (be->options2 & PR_O2_INDEPSTR)
 		s->si[1].flags |= SI_FL_INDEP_STR;
 
-	if (be->options2 & PR_O2_RSPBUG_OK)
-		s->txn.rsp.err_pos = -1; /* let buggy responses pass */
-	s->flags |= SF_BE_ASSIGNED;
-
 	/* If the target backend requires HTTP processing, we have to allocate
-	 * a struct hdr_idx for it if we did not have one.
+	 * the HTTP transaction and hdr_idx if we did not have one.
 	 */
-	if (unlikely(!s->txn.hdr_idx.v && be->http_needed)) {
-		s->txn.hdr_idx.size = global.tune.max_http_hdr;
-		if ((s->txn.hdr_idx.v = pool_alloc2(pool2_hdr_idx)) == NULL)
+	if (unlikely(!s->txn && be->http_needed)) {
+		if (unlikely(!http_alloc_txn(s)))
 			return 0; /* not enough memory */
 
 		/* and now initialize the HTTP transaction state */
 		http_init_txn(s);
 	}
 
-	/* If we chain to an HTTP backend running a different HTTP mode, we
-	 * have to re-adjust the desired keep-alive/close mode to accommodate
-	 * both the frontend's and the backend's modes.
-	 */
-	if (strm_sess(s)->fe->mode == PR_MODE_HTTP && be->mode == PR_MODE_HTTP &&
-	    ((strm_sess(s)->fe->options & PR_O_HTTP_MODE) != (be->options & PR_O_HTTP_MODE)))
-		http_adjust_conn_mode(s, &s->txn, &s->txn.req);
+	if (s->txn) {
+		if (be->options2 & PR_O2_RSPBUG_OK)
+			s->txn->rsp.err_pos = -1; /* let buggy responses pass */
 
-	/* If an LB algorithm needs to access some pre-parsed body contents,
-	 * we must not start to forward anything until the connection is
-	 * confirmed otherwise we'll lose the pointer to these data and
-	 * prevent the hash from being doable again after a redispatch.
-	 */
-	if (be->mode == PR_MODE_HTTP &&
-	    (be->lbprm.algo & (BE_LB_KIND | BE_LB_PARM)) == (BE_LB_KIND_HI | BE_LB_HASH_PRM))
-		s->txn.req.flags |= HTTP_MSGF_WAIT_CONN;
+		/* If we chain to an HTTP backend running a different HTTP mode, we
+		 * have to re-adjust the desired keep-alive/close mode to accommodate
+		 * both the frontend's and the backend's modes.
+		 */
+		if (strm_sess(s)->fe->mode == PR_MODE_HTTP && be->mode == PR_MODE_HTTP &&
+		    ((strm_sess(s)->fe->options & PR_O_HTTP_MODE) != (be->options & PR_O_HTTP_MODE)))
+			http_adjust_conn_mode(s, s->txn, &s->txn->req);
 
+		/* If an LB algorithm needs to access some pre-parsed body contents,
+		 * we must not start to forward anything until the connection is
+		 * confirmed otherwise we'll lose the pointer to these data and
+		 * prevent the hash from being doable again after a redispatch.
+		 */
+		if (be->mode == PR_MODE_HTTP &&
+		    (be->lbprm.algo & (BE_LB_KIND | BE_LB_PARM)) == (BE_LB_KIND_HI | BE_LB_HASH_PRM))
+			s->txn->req.flags |= HTTP_MSGF_WAIT_CONN;
+	}
+
+	s->flags |= SF_BE_ASSIGNED;
 	if (be->options2 & PR_O2_NODELAY) {
 		s->req.flags |= CF_NEVER_WAIT;
 		s->res.flags |= CF_NEVER_WAIT;
diff --git a/src/stream.c b/src/stream.c
index cd0f8bd..f12b2c3 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -425,7 +425,6 @@
 	struct session *sess = s->sess;
 	struct listener *l = sess->listener;
 	struct proxy *p = sess->fe;
-	struct http_txn *txn;
 	struct task *t = s->task;
 	struct connection *conn = __objt_conn(s->target);
 	int ret;
@@ -531,23 +530,7 @@
 	s->res.wex = TICK_ETERNITY;
 	s->res.analyse_exp = TICK_ETERNITY;
 
-	txn = &s->txn;
-	/* Those variables will be checked and freed if non-NULL in
-	 * stream.c:stream_free(). It is important that they are
-	 * properly initialized.
-	 */
-	txn->sessid = NULL;
-	txn->srv_cookie = NULL;
-	txn->cli_cookie = NULL;
-	txn->uri = NULL;
-	txn->hdr_idx.v = NULL;
-	txn->hdr_idx.size = txn->hdr_idx.used = 0;
-	txn->flags = 0;
-	txn->req.flags = 0;
-	txn->rsp.flags = 0;
-	/* the HTTP messages need to know what buffer they're associated with */
-	txn->req.chn = &s->req;
-	txn->rsp.chn = &s->res;
+	s->txn = NULL;
 
 	HLUA_INIT(&s->hlua);
 
@@ -591,7 +574,6 @@
  */
 static void stream_free(struct stream *s)
 {
-	struct http_txn *txn = &s->txn;
 	struct session *sess = strm_sess(s);
 	struct proxy *fe = sess->fe;
 	struct bref *bref, *back;
@@ -636,7 +618,8 @@
 		stream_offer_buffers();
 
 	hlua_ctx_destroy(&s->hlua);
-	http_end_txn(s);
+	if (s->txn)
+		http_end_txn(s);
 
 	/* ensure the client-side transport layer is destroyed */
 	if (cli_conn)
@@ -649,7 +632,12 @@
 		s->store[i].ts = NULL;
 	}
 
+	if (s->txn) {
+		pool_free2(pool2_hdr_idx, s->txn->hdr_idx.v);
+		pool_free2(pool2_http_txn, s->txn);
+		s->txn = NULL;
+	}
+
-	pool_free2(pool2_hdr_idx, txn->hdr_idx.v);
 	if (fe) {
 		pool_free2(fe->rsp_cap_pool, s->res_cap);
 		pool_free2(fe->req_cap_pool, s->req_cap);
@@ -1080,7 +1068,6 @@
 		}
 	}
 	else {
-		s->txn.rsp.msg_state = HTTP_MSG_RPBEFORE;
 		rep->flags |= CF_READ_DONTWAIT; /* a single read is enough to get response headers */
 	}
 
@@ -1404,7 +1391,7 @@
 			int ret = 1;
 
 			if (rule->cond) {
-				ret = acl_exec_cond(rule->cond, fe, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
+				ret = acl_exec_cond(rule->cond, fe, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
 				ret = acl_pass(ret);
 				if (rule->cond->pol == ACL_COND_UNLESS)
 					ret = !ret;
@@ -1457,7 +1444,7 @@
 		int ret = 1;
 
 		if (prst_rule->cond) {
-	                ret = acl_exec_cond(prst_rule->cond, s->be, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
+	                ret = acl_exec_cond(prst_rule->cond, s->be, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
 			ret = acl_pass(ret);
 			if (prst_rule->cond->pol == ACL_COND_UNLESS)
 				ret = !ret;
@@ -1486,7 +1473,8 @@
 	if (!(s->flags & SF_FINST_MASK))
 		s->flags |= SF_FINST_R;
 
-	s->txn.status = 500;
+	if (s->txn)
+		s->txn->status = 500;
 	s->req.analysers = 0;
 	s->req.analyse_exp = TICK_ETERNITY;
 	return 0;
@@ -1514,7 +1502,7 @@
 		list_for_each_entry(rule, &px->server_rules, list) {
 			int ret;
 
-			ret = acl_exec_cond(rule->cond, s->be, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
+			ret = acl_exec_cond(rule->cond, s->be, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
 			ret = acl_pass(ret);
 			if (rule->cond->pol == ACL_COND_UNLESS)
 				ret = !ret;
@@ -1579,7 +1567,7 @@
 			continue;
 
 		if (rule->cond) {
-	                ret = acl_exec_cond(rule->cond, px, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
+	                ret = acl_exec_cond(rule->cond, px, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL);
 			ret = acl_pass(ret);
 			if (rule->cond->pol == ACL_COND_UNLESS)
 				ret = !ret;
@@ -1588,7 +1576,7 @@
 		if (ret) {
 			struct stktable_key *key;
 
-			key = stktable_fetch_key(rule->table.t, px, s, &s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->expr, NULL);
+			key = stktable_fetch_key(rule->table.t, px, s, s->txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->expr, NULL);
 			if (!key)
 				continue;
 
@@ -1682,7 +1670,7 @@
 			continue;
 
 		if (rule->cond) {
-	                ret = acl_exec_cond(rule->cond, px, s, &s->txn, SMP_OPT_DIR_RES|SMP_OPT_FINAL);
+	                ret = acl_exec_cond(rule->cond, px, s, s->txn, SMP_OPT_DIR_RES|SMP_OPT_FINAL);
 	                ret = acl_pass(ret);
 			if (rule->cond->pol == ACL_COND_UNLESS)
 				ret = !ret;
@@ -1691,7 +1679,7 @@
 		if (ret) {
 			struct stktable_key *key;
 
-			key = stktable_fetch_key(rule->table.t, px, s, &s->txn, SMP_OPT_DIR_RES|SMP_OPT_FINAL, rule->expr, NULL);
+			key = stktable_fetch_key(rule->table.t, px, s, s->txn, SMP_OPT_DIR_RES|SMP_OPT_FINAL, rule->expr, NULL);
 			if (!key)
 				continue;
 
@@ -1780,7 +1768,8 @@
 	//        si_f->state, si_b->state, si_b->err_type, req->flags, res->flags);
 
 	/* this data may be no longer valid, clear it */
-	memset(&s->txn.auth, 0, sizeof(s->txn.auth));
+	if (s->txn)
+		memset(&s->txn->auth, 0, sizeof(s->txn->auth));
 
 	/* This flag must explicitly be set every time */
 	req->flags &= ~(CF_READ_NOEXP|CF_WAKE_WRITE);
@@ -2445,7 +2434,7 @@
 			    (s->be->server_id_hdr_name != NULL) &&
 			    (s->be->mode == PR_MODE_HTTP) &&
 			    objt_server(s->target)) {
-				http_send_name_header(&s->txn, s->be, objt_server(s->target)->id);
+				http_send_name_header(s->txn, s->be, objt_server(s->target)->id);
 			}
 
 			srv = objt_server(s->target);
@@ -2722,10 +2711,10 @@
 	s->logs.t_close = tv_ms_elapsed(&s->logs.tv_accept, &now);
 	stream_process_counters(s);
 
-	if (s->txn.status) {
+	if (s->txn && s->txn->status) {
 		int n;
 
-		n = s->txn.status / 100;
+		n = s->txn->status / 100;
 		if (n < 1 || n > 5)
 			n = 0;