New INFO field aof_delayed_fsync introduced.

This new field counts all the times Redis is configured with AOF enabled and
fsync policy 'everysec', but the previous fsync performed by the
background thread was not able to complete within two seconds, forcing
Redis to perform a write against the AOF file while the fsync is still
in progress (likely a blocking operation).

diff --git a/src/aof.c b/src/aof.c
index 83633217f796354649929880f6ed509cad552f32..4d3ce096acea3ae0019ba970c73b5024a1c313a2 100644 (file)
--- a/src/aof.c
+++ b/src/aof.c
@@ -108,6 +108,7 @@ void flushAppendOnlyFile(int force) {
             }
             /* Otherwise fall trough, and go write since we can't wait
              * over two seconds. */
+            server.aof_delayed_fsync++;
             redisLog(REDIS_NOTICE,"Asynchronous AOF fsync is taking too long (disk is busy?). Writing the AOF buffer without waiting for fsync to complete, this may slow down Redis.");
         }
     }

diff --git a/src/config.c b/src/config.c
index 238c9462f8ab61183604f47ae553f8babb748c84..d38ba72b13fa49a3539e66445d92848c69264c65 100644 (file)
--- a/src/config.c
+++ b/src/config.c
@@ -852,6 +852,7 @@ void configCommand(redisClient *c) {
         server.stat_numcommands = 0;
         server.stat_numconnections = 0;
         server.stat_expiredkeys = 0;
+        server.aof_delayed_fsync = 0;
         resetCommandTableStats();
         addReply(c,shared.ok);
     } else {

diff --git a/src/redis.c b/src/redis.c
index 44c75353ca549c9e803d31df46172b74a4f45929..39de86af6415ffffdc86c8fa61bfa2dd570df8e5 100644 (file)
--- a/src/redis.c
+++ b/src/redis.c
@@ -991,6 +991,7 @@ void initServerConfig() {
     server.aof_rewrite_base_size = 0;
     server.aof_rewrite_scheduled = 0;
     server.aof_last_fsync = time(NULL);
+    server.aof_delayed_fsync = 0;
     server.aof_fd = -1;
     server.aof_selected_db = -1; /* Make sure the first time will not match */
     server.aof_flush_postponed_start = 0;
@@ -1760,12 +1761,14 @@ sds genRedisInfoString(char *section) {
                 "aof_base_size:%lld\r\n"
                 "aof_pending_rewrite:%d\r\n"
                 "aof_buffer_length:%zu\r\n"
-                "aof_pending_bio_fsync:%llu\r\n",
+                "aof_pending_bio_fsync:%llu\r\n"
+                "aof_delayed_fsync:%lu\r\n",
                 (long long) server.aof_current_size,
                 (long long) server.aof_rewrite_base_size,
                 server.aof_rewrite_scheduled,
                 sdslen(server.aof_buf),
-                bioPendingJobsOfType(REDIS_BIO_AOF_FSYNC));
+                bioPendingJobsOfType(REDIS_BIO_AOF_FSYNC),
+                server.aof_delayed_fsync);
         }
 
         if (server.loading) {

diff --git a/src/redis.h b/src/redis.h
index c6498c459f75b7a0560d4e4adc6ea8c92732d43d..4b5c94dc3ead37d36ab44b1399b139983f681abb 100644 (file)
--- a/src/redis.h
+++ b/src/redis.h
@@ -509,6 +509,7 @@ struct redisServer {
     int aof_selected_db; /* Currently selected DB in AOF */
     time_t aof_flush_postponed_start; /* UNIX time of postponed AOF flush */
     time_t aof_last_fsync;            /* UNIX time of last fsync() */
+    unsigned long aof_delayed_fsync;  /* delayed AOF fsync() counter */
     /* RDB persistence */
     long long dirty;                /* Changes to DB from the last save */
     long long dirty_before_bgsave;  /* Used to restore dirty on failed BGSAVE */