一、现象实例名称：r-bp1cxxxxxxxxxd04（主从）问题：一分钟内存增加2G，如下图：键值规模：约6000万内存一分钟增加2G.png二、Redis内存分析1.内存组成上图中的内存统计的是Redis的infomemory命令中的used_memory属性，例如：redis>infomemory#Memoryused_memory:9195978072used_memory_human:8.56Gused_memory_rss:9358786560used_memory_peak:10190212744used_memory_peak_human:9.49Gused_memory_lua:38912mem_fragmentation_ratio:1.02mem_allocator:jemalloc-3.6.0各属性详细计算公式如下：used_memory=selfmemory+objectmemory+buffermemory+luamemoryused_rss=used_memory+memoryfragmentation如下图：二、内存分析（一）SelfMemory：一个空的Redis占用很少，可以忽略不计（2）kv内存：key对象+value对象（3）Buffer：clientbuffer（普通+slave伪装+pubsub）和aofbuffer（相对固定，一般没问题）（4）Lua：内存消耗bytheLuaengine3.内存突发常见问题(1)kvmemory:bigkey,largewrites(2)Clientbuffer:commonclientbuffer(例如monitorcommand)orpubsubclientbuffer3.Troubleshooting(1)bigkey?扫描后没有发现bigkey(2)键值数量增加？没有发现key值有明显变化（3）由于内存增加，客户端buffer已经很久没有掉线了。如果是缓冲区问题，从infoclients会发现一个明显的问题。执行后发现客户端执行没有明显问题当omem大于0时，id=80207addr=10.xx.0.4:63920fd=46name=age=624idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80215addr=10.xx.0.23:43489fd=36name=age=591idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80366addr=10.xx.0.8:59785fd=18name=age=84idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=delread=0write=0type=userid=80356addr=10.xx.0.33:32117fd=13name=age=114idle=0flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80064addr=10.xx.59.4:53446fd=38name=age=1070idle=1070flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=NULLread=0write=0type=adminid=80276addr=10.xx.0.23:48511fd=8name=age=387idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80188addr=10.xx.0.33:16265fd=42name=age=681idle=3flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80326addr=10.xx.0.32:59779fd=16name=age=209idle=0flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80065addr=10.xx.59.4:53447fd=45name=age=1070idle=1070flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=NULLread=0write=0type=adminid=79936addr=10.xx.0.22:10607fd=30name=age=1480idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80174addr=10.xx.0.5:60914fd=6name=age=722idle=2flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80300addr=10.xx.0.22:22757fd=48name=age=298idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80037addr=10.xx.0.5:55189fd=15name=age=1143idle=2flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80330addr=10.xx.0.8:48533fd=17name=age=199idle=10flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=79896addr=10.xx.0.30:26814fd=11name=age=1616idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80299addr=10.xx.0.24:11227fd=44name=age=303idle=3flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80086addr=10.xx.0.32:52526fd=40name=age=1002idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80202addr=10.xx.0.33：16658fd=26name=age=636idle=3flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80256addr=10.xx.0.24:60496fd=19name=age=448idle=2flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=79908addr=10.xx。0.29:18975fd=12name=age=1583idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80365addr=10.xx.0.29:46429fd=14name=age=85idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=79869addr=10.xx.27.4:48455fd=35name=age=1700idle=1700flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=NULLread=0write=0type=adminid=80334addr=10.xx.0.23:50012fd=39name=age=189idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80041addr=10.xx.0.32:51107fd=33name=age=1132idle=3flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=79992addr=10.xx.0.22:12068fd=28name=age=1289idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80251addr=10.xx.0.30:44213fd=23name=age=468idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80006addr=10.xx.0.2:45895fd=31name=age=1242idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80321addr=10.xx.0.30:48048fd=5name=age=224idle=3flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80381addr=10.xx.0.8:13360fd=22name=age=24idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=delread=0write=0type=userid=80200addr=10.xx.0.24:59183fd=24name=age=640idle=0flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80113addr=10.xx.0.2:52492fd=21name=age=915idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=174addr=11.216.117.242:53027fd=9name=age=281390idle=0flags=Sdb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=replconfread=0write=0type=adminid=79991addr=10.xx.0.4:48412fd=25name=age=1296idle=0flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80301addr=127.0.0.1:47869fd=49name=age=291idle=261flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=strlenread=0write=0type=adminid=80047addr=10.xx.59.4:53184fd=41name=age=1114idle=1114flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=NULLread=0write=0type=adminid=80236addr=10.xx.0.5:62546fd=47name=age=516idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80364addr=10.xx.0.4:18794fd=7name=age=85idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80175addr=10.xx.0.4:62245fd=29name=age=718idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80336addr=10.xx.0.29:45701fd=50name=age=180idle=1flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80050addr=10.xx.59.4:53188fd=43name=age=1114idle=1114flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=NULLread=0write=0type=adminid=79765addr=10.xx.0.2:33832fd=37name=age=2027idle=177flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=inforead=0write=0type=userid=80170addr=10.xx.0.2:57853fd=20name=age=728idle=24flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=0obl=0oll=0omem=0events=rcmd=pingread=0write=0type=userid=80390addr=127.0.0.1:49449fd=27name=age=0idle=0flags=Ndb=0sub=0psub=0multi=-1qbuf=0qbuf-free=32768obl=0oll=0omem=0events=rcmd=clientread=0write=0type=admin4.我已经使用了所有常见的技巧来找出罪魁祸首，但仍然没有用。同事@迷远帮忙一起分析，想知道是不是因为Redis的kv哈希表已经rehash1了。Redis的kv存储结构如下图所示。Redis的所有kv都存储在dict中，其中ht对应两个哈希表ht[0]和ht[1]。通常，一个闲置，另一个用于存储数据。只有当需要重新散列时，才会使用ht[1]。2.Redisdictionaryrehash为了保证哈希表的负载，当哈希表的元素个数等于哈希表槽的个数时，会进行rehash扩容。扩容后h[1]的容量等于前2n大于等于ht[0].size*2。比如哈希表的初始容量是4，那么下一次扩容是8，以此类推。3.测试(1)测试方法先在rehash阈值附近分批写入，然后逐条写入，观察内存变化。//为每个key设置1天的过期时间intexpireTime=60*60*24;//rehash阈值-50方便观察rehash内存变化intrehashThreshold=(int)Math.pow(2,25)-50;//1。batchwrite：pipeline批量写入，由于是本地测试，这里使用10000，实际生产时不使用所以使用Pipelinepipeline=jedis.pipelined();pipeline=jedis.pipelined();for(inti=0;i
