CODEWITHSUNDEEP
mongodb
Crashalot
Crashalot

Reputation: 34513

Cannot delete database in Mongo: it returns immediately (and mysteriously) after we delete it

when we run the show dbs command, the x-development database doesn't appear. then when we drop the database from the shell, it still allows us to access it again:

> use x-development
switched to db x-development
> db.dropDatabase()
{ "dropped" : "x-development", "ok" : 1 }
> use x-development
switched to db x-development
>

why is this happening? we're on mongo 2.2.

we're trying to drop the database because it appears under mongostat, and we want to make sure this database isn't taking server resources:

[root@mongo]# mongostat
connected to: 127.0.0.1
insert  query update delete getmore command flushes mapped  vsize    res faults               locked db idx miss %     qr|qw   ar|aw  netIn netOut  conn       time
     0      5      0      0       0       1       1  2.11g  4.86g   464m      0 x-development:0.0%          0       0|0     0|0    62b     2k     3   11:42:57
     0      0      0      0       0       1       0  2.11g  4.86g   464m      0 x-development:0.0%          0       0|0     0|0    62b     2k     3   11:42:58
     0      0      0      0       0       1       0  2.11g  4.86g   464m      0 x-development:0.0%          0       0|0     0|0    62b     2k     3   11:42:59

so the real question is: why is this database appearing under mongostat if the database doesn't exist?

Upvotes: 1

Views: 2586

Answers (2)

kirelagin
kirelagin

Reputation: 13616

In Mongo you don't create databases explicitly. You just start using it (for example by issuing a use statement) and it gets created automatically.

The database won't be using any resources if you don't query it. So, I don't think you should worry about it.

Upvotes: 0

Joachim Isaksson
Joachim Isaksson

Reputation: 180917

> db.dropDatabase()

...indeed drops the database. use can switch to any database, existing or not, it's not until you actually insert something that the database is recreated.

> show dbs
local (empty)

> use dev
switched to db dev

> show dbs
local (empty)

> db.test.insert({a:1})

> show dbs
dev 0.203125GB
local (empty)

> db.dropDatabase()
{ "dropped" : "dev", "ok" : 1 }

> show dbs
local (empty)

Upvotes: 3

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