本篇文章探讨了大数据技术之MongoDB误删表恢复，希望阅读本篇文章以后大家有所收获，帮助大家对相关内容的理解更加深入。

一、场景描述

    公司某工程师执行db.giveget_card.drop()，误将线上表删除。

    幸好每天都有做备份，这个时候就体现了备份的重要性了，哈哈哈。。。

二、模拟故障过程

备份数据大小：

rs_test01:PRIMARY> use ycsb
switched to db ycsb
rs_test01:PRIMARY> db.giveget_card.count();
3173391

删除之前，此表有更新。

rs_test01:PRIMARY> db.giveget_card.insert({id:1});
WriteResult({ "nInserted" : 1 })
rs_test01:PRIMARY> db.giveget_card.insert({id:2});
WriteResult({ "nInserted" : 1 })
rs_test01:PRIMARY> db.giveget_card.insert({id:3});
WriteResult({ "nInserted" : 1 })
rs_test01:PRIMARY> db.giveget_card.insert({id:4});
WriteResult({ "nInserted" : 1 })

其他表也有更新操作。

rs_test01:PRIMARY> db.tab.find();
{ "_id" : ObjectId("59354ba202d9a99ab2f879c6"), "name" : "a" }
{ "_id" : ObjectId("59354ba602d9a99ab2f879c7"), "name" : "b" }
{ "_id" : ObjectId("59354ba802d9a99ab2f879c8"), "name" : "c" }
{ "_id" : ObjectId("59354baa02d9a99ab2f879c9"), "name" : "d" }

删除操作之后，此表和其他表都有更新。

rs_test01:PRIMARY> db.giveget_card.find();
{ "_id" : ObjectId("59354c28d905432aeaccd53c"), "id" : 5 }
{ "_id" : ObjectId("59354c2bd905432aeaccd53d"), "id" : 6 }
rs_test01:PRIMARY> db.tab.find();
{ "_id" : ObjectId("59354ba202d9a99ab2f879c6"), "name" : "a" }
{ "_id" : ObjectId("59354ba602d9a99ab2f879c7"), "name" : "b" }
{ "_id" : ObjectId("59354ba802d9a99ab2f879c8"), "name" : "c" }
{ "_id" : ObjectId("59354baa02d9a99ab2f879c9"), "name" : "d" }
{ "_id" : ObjectId("59354ccfd905432aeaccd542"), "name" : "e" }
{ "_id" : ObjectId("59354cd2d905432aeaccd543"), "name" : "f" }

三、恢复步骤

1、将备份中 tab 表的 giveget_card.bson 及 giveget_card.metadata.json 文件拷贝到 /tmp/restore/ycsb 目录（自建目录)，ycsb 为库名。

# cp /data/backup/rs07/ycsb/giveget_card.* /tmp/restore/ycsb

2、将备份时间之后，误删操作之前的 oplog 导出，用于恢复表

# mongodump --port 2203 -d local -c oplog.rs -q '{"ts" : {$gte : Timestamp(1496664480, 10430), $lte : Timestamp(1496665113, 10430)}}' -o /tmp/oplog

--时间戳 是使用转换工具转换之后的结果。

3、使用 bsondump 查看 oplog 日志，找到 drop 操作的时间戳 1496665069

# bsondump /tmp/oplog/local/oplog.rs.bson 
{"ts":{"$timestamp":{"t":1496664760,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"7079172056815894727"},"v":2,"op":"i","ns":"ycsb.giveget_card","o":{"_id":{"$oid":"59354ab8c5308d8c7a9da8b5"},"id":1.0}}
{"ts":{"$timestamp":{"t":1496664762,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"-1797107728294067016"},"v":2,"op":"i","ns":"ycsb.giveget_card","o":{"_id":{"$oid":"59354abac5308d8c7a9da8b6"},"id":2.0}}
{"ts":{"$timestamp":{"t":1496664765,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"8604646791509150392"},"v":2,"op":"i","ns":"ycsb.giveget_card","o":{"_id":{"$oid":"59354abdc5308d8c7a9da8b7"},"id":3.0}}
{"ts":{"$timestamp":{"t":1496664768,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"9018614066505371436"},"v":2,"op":"i","ns":"ycsb.giveget_card","o":{"_id":{"$oid":"59354ac0c5308d8c7a9da8b8"},"id":4.0}}
{"ts":{"$timestamp":{"t":1496664994,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"-4471524661347063602"},"v":2,"op":"c","ns":"ycsb.$cmd","o":{"create":"tab"}}
{"ts":{"$timestamp":{"t":1496664994,"i":2}},"t":{"$numberLong":"12"},"h":{"$numberLong":"-4215905958456607246"},"v":2,"op":"i","ns":"ycsb.tab","o":{"_id":{"$oid":"59354ba202d9a99ab2f879c6"},"name":"a"}}
{"ts":{"$timestamp":{"t":1496664998,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"6170506962401844481"},"v":2,"op":"i","ns":"ycsb.tab","o":{"_id":{"$oid":"59354ba602d9a99ab2f879c7"},"name":"b"}}
{"ts":{"$timestamp":{"t":1496665000,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"-8071456063660489895"},"v":2,"op":"i","ns":"ycsb.tab","o":{"_id":{"$oid":"59354ba802d9a99ab2f879c8"},"name":"c"}}
{"ts":{"$timestamp":{"t":1496665002,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"4387884836668659146"},"v":2,"op":"i","ns":"ycsb.tab","o":{"_id":{"$oid":"59354baa02d9a99ab2f879c9"},"name":"d"}}
{"ts":{"$timestamp":{"t":1496665069,"i":1}},"t":{"$numberLong":"12"},"h":{"$numberLong":"-6913449254950935781"},"v":2,"op":"c","ns":"ycsb.$cmd","o":{"drop":"giveget_card"}}
2017-06-05T20:27:25.552+0800 10 objects found

4、将 oplog 的 bson 文件拷贝到相应目录下

# cp /tmp/oplog/local/oplog.rs.bson /tmp/restore/oplog.bson

此时恢复的目录结构：

# pwd
/tmp/restore
# ls
oplog.bson  ycsb

5、至此，所有的准备操作已经做完，恢复数据。

[root@ops-db-test02 restore]# mongorestore --port 2203 --oplogReplay --oplogLimit=1496665069:1 /tmp/restore
2017-06-05T20:36:45.361+0800 building a list of dbs and collections to restore from /tmp/restore dir
2017-06-05T20:36:45.364+0800 reading metadata for ycsb.giveget_card from /tmp/restore/ycsb/giveget_card.metadata.json
2017-06-05T20:36:45.364+0800 restoring ycsb.giveget_card from /tmp/restore/ycsb/giveget_card.bson
2017-06-05T20:36:48.362+0800 [........................]  ycsb.giveget_card  15.4MB/475MB  (3.2%)
2017-06-05T20:36:51.362+0800 [#.......................]  ycsb.giveget_card  31.1MB/475MB  (6.6%)
2017-06-05T20:36:54.362+0800 [##......................]  ycsb.giveget_card  46.6MB/475MB  (9.8%)
2017-06-05T20:36:57.362+0800 [###.....................]  ycsb.giveget_card  62.1MB/475MB  (13.1%)
2017-06-05T20:37:00.362+0800 [###.....................]  ycsb.giveget_card  76.4MB/475MB  (16.1%)
2017-06-05T20:37:03.362+0800 [####....................]  ycsb.giveget_card  90.7MB/475MB  (19.1%)
2017-06-05T20:37:06.362+0800 [#####...................]  ycsb.giveget_card  105MB/475MB  (22.0%)
2017-06-05T20:37:09.362+0800 [######..................]  ycsb.giveget_card  120MB/475MB  (25.2%)
2017-06-05T20:37:12.362+0800 [######..................]  ycsb.giveget_card  133MB/475MB  (28.0%)
2017-06-05T20:37:15.362+0800 [#######.................]  ycsb.giveget_card  146MB/475MB  (30.8%)
2017-06-05T20:37:18.363+0800 [########................]  ycsb.giveget_card  163MB/475MB  (34.3%)
2017-06-05T20:37:21.362+0800 [########................]  ycsb.giveget_card  178MB/475MB  (37.4%)
2017-06-05T20:37:24.362+0800 [#########...............]  ycsb.giveget_card  196MB/475MB  (41.3%)
2017-06-05T20:37:27.362+0800 [##########..............]  ycsb.giveget_card  214MB/475MB  (45.0%)
2017-06-05T20:37:30.362+0800 [###########.............]  ycsb.giveget_card  231MB/475MB  (48.6%)
2017-06-05T20:37:33.362+0800 [############............]  ycsb.giveget_card  245MB/475MB  (51.5%)
2017-06-05T20:37:36.362+0800 [#############...........]  ycsb.giveget_card  261MB/475MB  (54.8%)
2017-06-05T20:37:39.362+0800 [<span class    

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