miércoles, 19 de diciembre de 2012

MongoDb Videos

This is the wiki for **10gen**'s _MongoDB for DBAs / Administrators_.

[Welcome to the MongoDB Community](

**Week 7**

* Youtube playlist link for week 7: [Week 7 playlist link](

**Week 6**

* Youtube Playlist link for week 6: [Week 6 playlist link](

* Video lengths for week 6 can be found in [this forum post]( There are 10 lessons that range in length from 02:27 to 18:16. Enjoy.


**Week 5**

* Youtube Playlist [Link of youtube playlist for week 5](

* Video lengths can be found in [this forum post]( The lengths of the videos have been returned to managable time frames with the longest being just over 15 minutes in length.

* [List of youtube links](

**Week 4**

* Youtube Playlist link for week 4: [Week 4 playlist link](

* Video lengths can be found in [this forum post]( The videos are longer than usual this week.
* [List of youtube links](
* Correction: _One of the lecture videos says you can use --fork on Windows; however you cannot._ Just open a separate CMD.EXE instead or use START in the command prompt window.
** [Short Windows demo here](
* Homework 4.4 assumes you created your replica set members with `_id` values of `0`, `1` and `2`. There is a [forum post]( that calls this out.

**Week 3**

* The mapReduce gist from this week’s lesson can be found here: [MongoDB map reduce example 2](

* Note from Monday Nov 5: Week 3 is in editing. Later today we will announce exact timing of availabity (it won't be today). Apologies power was out most of the previous week here...

* [List of youtube links](

* Youtube Playlist link for week 3: [Week 3 playlist link](

**Week 2**

* Youtube Playlist link for week 2: [Week 2 playlist link](

**Week 1**

* Youtube Playlist link for week 1: [Week 1 playlist link](

* Correction: I believe somewhere in the videos I may have referred to SQL as "procedural" -- I meant to say "non-procedural". dm

* [**[HowTo] **watch or download courseware from youtube directly](

* [Whitespace in JSON syntax](

* Where to find products.json file : [](

* Note: we are working on the issue with the homework submissions more to come...

martes, 18 de diciembre de 2012

Mongodb DBA Test finished.

Por fin, pude acabar los 11 puntos del exámen de MongoDb DBA, mañana espero revisarlos y para el jueves esperar el resultado.

Veremos que pasa, tengo dudas con dos.

Finally, I finished the 11-point test of MongoDB DBA, tomorrow I hope to review them and wait for the result on Thursday.

Hasta el 20 no hay resultados.

En los últimos ejercicios tuve que montar 4 instancias de Mongodb, Sharding, Config Srv... de todo.

viernes, 14 de diciembre de 2012

MongoDb DBA Exam

Ya tengo resuelto los primeros 5 puntos del exámen. Creo que en unos dias podré pedir mi certificado.

Now, we want to see if any data that we attempted to insert isn't there. Go into the shell to any member of the set. Use rs.status() to check state. Be sure the member is "caught up" to the latest optime (if it's a secondary). Also on a secondary you might need to invoke rs.slaveOk() before doing a query.)

Now run:


to see what data is there after the set recovered from the two outages. How many documents do you have?

Question: which one of the following is the true statement about mongodb's operation in these scenarios?

a. Mongo preserves the order of writes in a collection in its consistency model. In this problem, 27003's oplog was effectively a "fork" and to preserve write ordering a rollback was necessary during 27003's recovery phase.

b. The MongoDB primary does not write to its datafiles until a majority acknowledgement comes back from the rest of the cluster.

c. When 27003 was primary, that was never received for writes 7,8,9.When 27003 came back up, it transmitted its write ops that the other members had not seen yet to those members so that they would have them also.

Final: Final.3

In Final.2 the mongod on port 27003 does a rollback. Go to that mongod's data directory. Look for a rollback directory inside. Find the .bson file there. Run the bsondump utility on that file. What are its contents?
There is no such file.
The file exists but is 0 bytes long.

It contains 2 documents.
It contains 3 documents.
It contains 4 documents.
It contains 8 documents.

Make that change to the set -- i.e. reconfig so that the third member can *never* be primary. Then run:

$ mongo --shell a.js --port 27003

And run

> part4()

And enter the result in the text box below (with no spaces or line feeds just the exact value returned).

Final: Final.5

Suppose we have blog posts in a (not sharded*) postings collection, of the form:

_id : …,
author : 'joe',
title : 'Too big to fail',
text : …,
tags : [ 'business', 'finance' ],
when : ISODate("2008-11-03"),
views : 23002,
votes : 4,
voters : ['joe', 'jane', 'bob', 'somesh'],
comments : [
{ commenter : 'allan',
comment : 'Well, i don't think so…',
flagged:false, plus:2 },

Which of these statements is true? Note: to get a multiple answer question right in this final you must get all the components right, so even if some parts are simple, take your time.

*Certain restrictions apply to unique constraints on indexes when sharded, so I mentioned to be clear.

Gracias 10 GEN !!!!

TrixBox no more free

Lamentáblemente otra de las empresas que no pueden soportar mas el costo de "GRATIS" en los servicios, y solamente darán servicios pagos.

Trixbox, era una de las distros mas sencillas para montar un Asterisk (VOIP) en Linux, hoy recibí el correo de que dejará de dar soporte gratis.

Thanks for your previous participation in the trixbox CE community. Though we have discontinued the free, Community Edition of trixbox, we hope you'll explore the superior features, functionality, support and increased stability that trixbox Pro provides. And now, for a limited time, Fonality is offering a 30% discount* to trixbox CE community members who upgrade to trixbox Pro.

Fonality is also pleased to offer other special promotions to the trixbox CE community on hosted and on-premise business phone and communications solutions. For example, for a limited time, customers purchasing one-year of cloud-based business phone service from Fonality with Voicemail Transcription, Screen Share and Heads Up Display Mobile can get the second year free.*

Let us know how we can be of service. We look forward to hearing from you soon.

The Fonality Communications Team

Tendencias Búsq

Tendencias de lo que se busca por Google en el mundo, en este caso ESPAÑA.

SQL to Mongo

Gracias a Juan M. Palma que me envió este link, ya es posible que una página en internet te haga la conversión entre código SQL (ansi 92) y MongoDB.

Muy buena alternativa para ver como pasar código, aunque en algunos casos lo que indica la página no me gusta.


Ya está disponible el TEST final para MongoDB DBA, son 11 puntos con un nivel elevado, y tendré que ponerme a hacer uno a uno los ejercicios con atención.

Casi todas las preguntas está relacionadas con replicación, servicios, caidas, etc. Algo que me parece lógica para un DBA.

En cuanto tenga hechos todos los puntos comentaré mas cosas, no mucho para que no se copien las respuestas.


En la próxima semana estaré con MemSQLd, un servicio para aumentar la velocidad de MySQL utilizando RAM y una capa en medio, entre el servidor y el cliente.

En esta página se puede bajar una copia del APP para probar.

lunes, 10 de diciembre de 2012

MongoDB Week6

He pasado nuevamente en el límite la semana 6 del curso oficial de 10GEN de MongoDB.
En estas semanas vimos replicaciones y shardering, dos temas fundamentales y de uso diario en MongoDB.

Tengo que reconocer que aprendí bastante sobre los conocimientos que tenía luego de leer dos libros (antes del curso).

Estoy viendo como implementaremos MongoDB en nuestro nuevo proyecto, algo que sería realmente revolucionario.