MongoDB Oplog入門
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This document demonstrates how the oplog in MongoDB replica sets works by replicating operations from the primary to secondaries. It shows insert, update, remove operations on a collection on the primary and then verifies that the same operations have been replicated to the oplog and applied on a secondary by finding the same document changes. It also shows getMore commands from secondaries tailing the oplog on the primary to stay up to date as new operations are applied.
![Wed Jun 8 23:53:38 [conn6] getmore local.oplog.rs cid:3687673685314762755 getMore:
{ ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3022ms
Wed Jun 8 23:53:38 [conn8] getmore local.oplog.rs cid:9178181051262829411 getMore:
{ ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3046ms
Wed Jun 8 23:53:41 [conn8] getmore local.oplog.rs cid:9178181051262829411 getMore:
{ ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3041ms
Wed Jun 8 23:53:41 [conn6] getmore local.oplog.rs cid:3687673685314762755 getMore:
{ ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3043ms
...](https://image.slidesharecdn.com/oplog-110628043637-phpapp02/85/MongoDB-Oplog-21-320.jpg)
MongoDB Oplog入門
- 19. myset:PRIMARY> db.mycoll.insert({x:1}) myset:PRIMARY> db.mycoll.update({x:1}, {$set : {y:1}}) myset:PRIMARY> db.mycoll.update({x:2}, {$set : {y:1}}, true) myset:PRIMARY> db.mycoll.remove({x:1}) myset:PRIMARY> db.mycoll.find() { "_id" : ObjectId("4def8e5fb07da951204c60e0"), "x" : 1, "y" : 1 } { "_id" : ObjectId("4def8e5fd60f868d9ea77776"), "x" : 2, "y" : 1 }
- 20. myset:PRIMARY> use local myset:PRIMARY> db.oplog.rs.find().sort({$natural:-1}) { "ts" : { "t" : 1307545183000, "i" : 4 }, "h" : NumberLong("-1214445074120755058"), "op" : "d", "ns" : "test.mycoll", "b" : true, "o" : { "_id" : ObjectId("4def8e5fb07da951204c60e0") } } { "ts" : { "t" : 1307545183000, "i" : 3 }, "h" : NumberLong("296197708926251535"), "op" : "i", "ns" : "test.mycoll", "o" : { "_id" : ObjectId("4def8e5fd60f868d9ea77776"), "x" : 2, "y" : 1 } } { "ts" : { "t" : 1307545183000, "i" : 2 }, "h" : NumberLong("6923456793495821492"), "op" : "u", "ns" : "test.mycoll", "o2" : { "_id" : ObjectId("4def8e5fb07da951204c60e0") }, "o" : { "$set" : { "y" : 1 } } } { "ts" : { "t" : 1307545183000, "i" : 1 }, "h" : NumberLong("-4148240362977057242"), "op" : "i", "ns" : "test.mycoll", "o" : { "_id" : ObjectId("4def8e5fb07da951204c60e0"), "x" : 1 } } ...
- 21. Wed Jun 8 23:53:38 [conn6] getmore local.oplog.rs cid:3687673685314762755 getMore: { ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3022ms Wed Jun 8 23:53:38 [conn8] getmore local.oplog.rs cid:9178181051262829411 getMore: { ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3046ms Wed Jun 8 23:53:41 [conn8] getmore local.oplog.rs cid:9178181051262829411 getMore: { ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3041ms Wed Jun 8 23:53:41 [conn6] getmore local.oplog.rs cid:3687673685314762755 getMore: { ts: { $gte: new Date(5615858237044687812) } } bytes:20 nreturned:0 3043ms ...
- 22. myset:SECONDARY> db.oplog.rs.find().sort({$natural:-1}) { "ts" : { "t" : 1307545183000, "i" : 4 }, "h" : NumberLong("-1214445074120755058"), "op" : "d", "ns" : "test.mycoll", "b" : true, "o" : { "_id" : ObjectId("4def8e5fb07da951204c60e0") } } { "ts" : { "t" : 1307545183000, "i" : 3 }, "h" : NumberLong("296197708926251535"), "op" : "i", "ns" : "test.mycoll", "o" : { "_id" : ObjectId("4def8e5fd60f868d9ea77776"), "x" : 2, "y" : 1 } } { "ts" : { "t" : 1307545183000, "i" : 2 }, "h" : NumberLong("6923456793495821492"), "op" : "u", "ns" : "test.mycoll", "o2" : { "_id" : ObjectId("4def8e5fb07da951204c60e0") }, "o" : { "$set" : { "y" : 1 } } } { "ts" : { "t" : 1307545183000, "i" : 1 }, "h" : NumberLong("-4148240362977057242"), "op" : "i", "ns" : "test.mycoll", "o" : { "_id" : ObjectId("4def8e5fb07da951204c60e0"), "x" : 1 } } ...