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Hello, We have a single replica set with 3 nodes running 3.4.14 with WiredTiger. After dropping lots of collections frequently, we found the file sizeStorer.wt is growing up slowly the mem of mongod grow slowly finally mongod was killed by oom-killer, and sizeStorer.wt grow up to 300MB Test script db = db.getSiblingDB("testdb"); var count = 0; do{ col = db.getCollection("sizeStore"); col.insert({"name":"aa"}); doc=col.findOne(); printjson(doc) db.sizeStore.drop(); sleep(1); count ++; print("create table count " +count); }while(true) * sizeStorer.wt size:（create/drop table/ count 3130104） -rw------- 1 Ruby Ruby 49 Feb 25 02:59 WiredTiger -rw------- 1 Ruby Ruby 21 Feb 25 02:59 WiredTiger.lock -rw------- 1 Ruby Ruby 1011 Feb 28 07:20 WiredTiger.turtle -rw------- 1 Ruby Ruby 548864 Feb 28 07:20 WiredTiger.wt -rw------- 1 Ruby Ruby 4096 Feb 26 00:55 WiredTigerLAS.wt -rw------- 1 Ruby Ruby 36864 Feb 27 21:25 _mdb_catalog.wt drwx------ 4 Ruby Ruby 4096 Feb 25 02:59 admin drwx------ 2 Ruby Ruby 4096 Feb 28 07:20 diagnostic.data drwx------ 2 Ruby Ruby 4096 Feb 27 19:36 journal drwx------ 4 Ruby Ruby 4096 Feb 25 02:59 local -rw------- 1 Ruby Ruby 5 Feb 26 00:55 mongod.lock -rw------- 1 root root 81 Feb 26 01:58 monitor.sh -rw------- 1 Ruby Ruby 303792128 Feb 28 07:20 sizeStorer.wt -rw------- 1 Ruby Ruby 95 Feb 25 02:59 storage.bson drwx------ 4 Ruby Ruby 4096 Feb 25 10:28 testdb * OOM: Feb 27 21:24:49 localhost kernel: [239239.871767] Out of memory: Kill process 13316 (mongod) score 863 or sacrifice child Feb 27 21:24:49 localhost kernel: [239239.871801] Killed process 13316 (mongod) total-vm:6096592kB, anon-rss:3286352kB, file-rss:0kB Feb 27 21:24:49 localhost kernel: [239239.873442] systemd-journal: page allocation failure: order:0, mode:0x201da Feb 27 21:24:49 localhost kernel: [239239.873445] CPU: 1 PID: 451 Comm: systemd-journal Tainted: G OE ----V------- 3.10.0-327.62.59.83.h128.x86_64 #1 Feb 27 21:24:49 localhost kernel: [239239.873446] Hardware name: OpenStack Foundation OpenStack Nova, BIOS rel-1.10.2-0-g5f4c7b1-20181220_000000-szxrtosci10000 04/01/2014 Feb 27 21:24:49 localhost kernel: [239239.873447] Call Trace: The above scenario is just a simplification of our business. In actual business, we create and delete almost 30000 collections per day. Approximately every 10 days, our business also meet database crash by OOM-killer. So I would like to know: How often does Mongodb support DDL operations? Thanks for your help.

Top User Comments

carl.champain commented on Fri, 28 Feb 2020 14:44:58 +0000: Hi 2669706182@qq.com, MongoDB 3.4 is already end-of-lifed, which means it is unsupported by us. We strongly recommend you upgrade to a supported version. That said, the SERVER project is for bugs and feature suggestions for the MongoDB server. As this ticket does not appear to be a bug, I will now close it. If you need assistance troubleshooting, I encourage you to ask our community by posting on the mongodb-user group or on Stack Overflow with the mongodb tag. Kind regards, Carl

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