From: Daniel Salzman <daniel.salzman@nic.cz>
Date: Thu, 4 Sep 2025 08:15:10 +0000 (+0200)
Subject: redis: write RRsets in batches to reduce processing overhead
X-Git-Tag: v3.5.0~11^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b417798f6285d37a996a18eabac3ede98636164b;p=thirdparty%2Fknot-dns.git

redis: write RRsets in batches to reduce processing overhead
---

diff --git a/src/knot/zone/redis.c b/src/knot/zone/redis.c
index d287fc56c5..e380476c99 100644
--- a/src/knot/zone/redis.c
+++ b/src/knot/zone/redis.c
@@ -12,6 +12,8 @@
 #include "contrib/openbsd/strlcpy.h"
 #include "knot/common/hiredis.h"
 
+#define UNREAD_MAX 20 // Redis write batch length.
+
 struct redisContext *zone_redis_connect(conf_t *conf)
 {
 	return rdb_connect(conf);
@@ -77,6 +79,7 @@ int zone_redis_txn_begin(zone_redis_txn_t *txn, struct redisContext *rdb,
 	txn->origin_len = knot_dname_size(zone_name);
 	txn->incremental = incremental;
 	txn->removals = false;
+	txn->unread = 0;
 	txn->err[0] = '\0';
 
 	const char *cmd = txn->incremental ? RDB_CMD_UPD_BEGIN  " %b %b" :
@@ -100,6 +103,33 @@ int zone_redis_txn_begin(zone_redis_txn_t *txn, struct redisContext *rdb,
 	return KNOT_EOK;
 }
 
+static int finish_unread(zone_redis_txn_t *txn, size_t max)
+{
+	if (txn->unread < max) {
+		return KNOT_EOK;
+	}
+
+	int ret = KNOT_EOK;
+
+	redisReply *reply;
+	for (size_t i = 0; i < max; i++) {
+		if (redisGetReply(txn->rdb, (void **)&reply) == REDIS_OK) {
+			if (ret == KNOT_EOK) {
+				ret = check_reply(txn->rdb, reply, REDIS_REPLY_STATUS, txn->err);
+			}
+			freeReplyObject(reply);
+		} else {
+			if (ret == KNOT_EOK) {
+				ret = check_reply(txn->rdb, NULL, REDIS_REPLY_ERROR, txn->err);
+			}
+		}
+	}
+
+	txn->unread -= max;
+
+	return ret;
+}
+
 int zone_redis_write_rrset(zone_redis_txn_t *txn, const knot_rrset_t *rr)
 {
 	if (txn == NULL || rr == NULL || (txn->removals && !txn->incremental)) {
@@ -110,19 +140,17 @@ int zone_redis_write_rrset(zone_redis_txn_t *txn, const knot_rrset_t *rr)
 	                  txn->removals ?     RDB_CMD_UPD_REMOVE " %b %b %b %d %d %d %b" :
 	                                      RDB_CMD_UPD_ADD    " %b %b %b %d %d %d %b";
 
-	redisReply *reply = redisCommand(txn->rdb, cmd, txn->origin, txn->origin_len,
-	                                 &txn->rdb_txn, sizeof(txn->rdb_txn),
-	                                 rr->owner, knot_dname_size(rr->owner), rr->type, rr->ttl,
-	                                 rr->rrs.count, rr->rrs.rdata, rr->rrs.size);
-	int ret = check_reply(txn->rdb, reply, REDIS_REPLY_STATUS, txn->err);
-	if (ret != KNOT_EOK) {
-		freeReplyObject(reply);
-		return ret;
+	int ret = redisAppendCommand(txn->rdb, cmd, txn->origin, txn->origin_len,
+	                             &txn->rdb_txn, sizeof(txn->rdb_txn),
+	                             rr->owner, knot_dname_size(rr->owner), rr->type, rr->ttl,
+	                             rr->rrs.count, rr->rrs.rdata, (size_t)rr->rrs.size);
+	if (ret != REDIS_OK) {
+		return check_reply(txn->rdb, NULL, REDIS_REPLY_ERROR, txn->err);
 	}
 
-	freeReplyObject(reply);
+	txn->unread++;
 
-	return KNOT_EOK;
+	return finish_unread(txn, UNREAD_MAX);
 }
 
 int zone_redis_write_node(zone_redis_txn_t *txn, const zone_node_t *node)
@@ -146,12 +174,17 @@ int zone_redis_txn_commit(zone_redis_txn_t *txn)
 		return KNOT_EINVAL;
 	}
 
+	int ret = finish_unread(txn, txn->unread);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
 	const char *cmd = txn->incremental ? RDB_CMD_UPD_COMMIT  " %b %b" :
 	                                     RDB_CMD_ZONE_COMMIT " %b %b";
 
 	redisReply *reply = redisCommand(txn->rdb, cmd, txn->origin, txn->origin_len,
 	                                 &txn->rdb_txn, sizeof(txn->rdb_txn));
-	int ret = check_reply(txn->rdb, reply, REDIS_REPLY_STATUS, txn->err);
+	ret = check_reply(txn->rdb, reply, REDIS_REPLY_STATUS, txn->err);
 	if (ret != KNOT_EOK) {
 		freeReplyObject(reply);
 		return ret;
@@ -169,6 +202,8 @@ int zone_redis_txn_abort(zone_redis_txn_t *txn)
 		return KNOT_EINVAL;
 	}
 
+	(void)finish_unread(txn, txn->unread);
+
 	const char *cmd = txn->incremental ? RDB_CMD_UPD_ABORT  " %b %b" :
 	                                     RDB_CMD_ZONE_ABORT " %b %b";
 
diff --git a/src/knot/zone/redis.h b/src/knot/zone/redis.h
index 8be96dfc75..df581efa3b 100644
--- a/src/knot/zone/redis.h
+++ b/src/knot/zone/redis.h
@@ -29,6 +29,8 @@ typedef struct {
 	bool incremental;
 	bool removals;
 
+	size_t unread;
+
 	zone_redis_err_t err;
 } zone_redis_txn_t;