Monday, August 22, 2011

Is Jan Lokpal really worth for what its been talked about?

Came across an article on The Hindutimes: http://www.thehindu.com/todays-paper/tp-opinion/article2380789.ece#.TlJ3aKOaibt.facebook

Nice points, can be taken into considerations. but few things still remains as is:
1. Good points about the donations that they are getting from. I think they should make it available on their websites with audits details and Incometax details.

2. Yes, even I get fadeup of news channel when they dont have anything else to show n their so called "News Channel" That too showing things 1000s of times again and again. But not showing/doing real intellectual debate/discussion on the same. Even if they do so, that are time bounded, hardly 30 mins. It should be given enough of time to discuss upon. Its not that Janlokpal bill drafted by Anna and team is THe best, might be some decisions by Govt. bill are good for some reasons. But then they should be discussed and clarified at the public level. Govt. should come-out and give a detailed explanation of why they feel threat on some demands of the Janlokpal bill which might spoil the public interest, and so that can not be accommodated.

3. She is claiming that some things  in that Demands are unlike Gandhians. We should not forget that gandhi also never asked to get half independance. He also asked for "Sampurna Swaraaj,...Complete Independance!!" from Britishers. To  Britisher, at that time, this demand was also a huge demand. Something they never wanted to grant so easily. So we should not compare that way atleast while saying that current demand is not Gadhian.

4. Agreed that this movement has got way more traction compared to other movements. But again, can't we feel that this has been kind better organized in a way? And that this touches the very root cause of the problem that every individual is facing? "CORRUTPTION" ? May be this is oone more reason why it got so much of attraction, as its more generic in nature. Name any issue that we face in our daily life,, most of them drilled down, and we feel that its some sort of corruption at some level which caused the issue. Call it in-efficient PDS system, improper Food storage system, bad shape of Public schools, Hospitals etc.
 
5.Yes, agree with point that they asking to create a Huge (Draconian???) thing in  parallel in a way when looked from narrow perspective. But its not always true. There are so many reasons why we need a powerful mechanism function operating. One might get those reasons if  see through (all) following videos : http://www.youtube.com/watch?v=2CHcKlIsvAQ&feature=share
   Biggest problem we have is that, we dont have big and clean Nationalized party/ies with us now whom we can elect. BJP and Congress are the only two truely speaking big and nationalized parties with us. We have tried both of them in last 60 yrs.
    Its not that we have not done any progress. We definitely have. But again look around and look how concentrated the growths are at few places only. Our villages are still far from even basic needs fulfillment. Even post 60KM radius of Mumbai, Capital Hub of Country not having proper Light, Water supply, Roads!! I have been to the places (hardly 15 KM away from Virar) and experienced it. Then only I am writing this. I am not saying the govt. is the only one responsible for this mess. But They are def. one of the reasons for the mess. Its the duty of leader to guide people. Be a role model.  

6. When said that this Janlokpal will create a huge and powerful system, yes there is always a risk!! But I want to ask all, do they think "Autocracy is Bad and democracy is Good?" I dont believe so. Everything is good, if the power is in right hand. Even Autocracy can be better than Democracy at that time. Even in democracy, we eventually endup giving power to few people whom we elect. What if they go mad after getting power in their hand ? Risk remains the same!! How can Shibu shoren reach to a level where he is when there are so many allegations on him?

    Our democracy giving us right to elect  ... but are we getting right candidates to elect from??
 
7. We have already tried giving power to them, it has not worked all well, and we know that. Why not we try this if one still feel that this can be a monster.We anyways are not  in shade of angel right now!!

8. What does she meant by "Contrary to Gandhiji's ideas about the decentralisation of power". If that was so, why we had PM that time. Why we were trying to reunite the small statets like Hydrabad, Kashmir etc? If there is a single country, there also has to be a atelast some single source of power at some level to bring in all power across. Even in Jan lokpal, there is something called as "Lokayukta" and "Lokpal", Lokayukta is at center level and Lokpal at the state level.
 

Came across one more article today. Worth reading it. It gives many answers as well asked by dear Arundhati. : http://clearvisor.wordpress.com/2011/08/23/why-i--rather-be-anna-than-arundhati/

     So not sure why we calling it as a single huge draconian? Isn't it relatively safer when its says that all evidences will be available to public once the charge of misconduct is proved ? Or we love our system where Bhopal gas tragedy case never ends, Bofors scam get a clean chit, those who are accused can at max spend few years (if atall sent to jail) and then enjoy rest of the life as the loss to public money is never recovered from them!!

Saturday, August 20, 2011

Why Janlokpal, and should it be JUST Janlok Pal only??


Here is an interview of Mr. Nandan Nilekani and his view for the Jan Lokapal bill and the reactions of Public over it.




First of all sorry for long Kathaa below. You can skip from reading it :p

    I agree with his point that Lokpal alone will NOT shunt corruption, but at one point he says that he doesn't understand why this has got so much of traction. Thats what surprised me!!

1.   See, not every can think/foresee in broadway. Like himself, he was repeating UId for most of the discussion part, saying it can  be a area where with improvisation, things can streamedlined, agreed. He is expert of his domain, so he knows how to get best out of it. Anna is carrying different background, he is expert in his domain, and trying to get best results via that. He might be thinking in much broader way than he talked here, but he either didn't or couldn't speak because of whatever reasons, but we all have to agree that its not a overnight change. As he himself said its like a revolution of expectations. So we can't change everything in one go. So may be we can take this thing as a first step of a long journey.

   Its like collective effort from all sides which can make a better world (NOT JUST INDIA)!! WHo knows which other country can take some inspiration from this :)

2. There are so many reasons why people are NOT in state to rely on the Standing committee and other advisory boards ONLY. He claims that all doing great jobs. They might be, but how many times put of  100 things they do? If things are really so, how can so many scams (mines, 2G, CWG) can happen so easily? How can these things happen so consistently?
    May be because of Lack Accountability and unlimited freewill/power, maybe upto certain extent.

     Public pressure is there, just to make sure that, they realize the fact that "This time People ARE WATCHING THEM" and this is NOT gonna be just another sugar coated pill they can give us and fall a sleep again.

3. If you see a cop on road talking with a driver, what is the first thing that comes in our mind?? The answer to this Q would tell why we want some Monitor over all of us. Its not that Govt. only is corrupt. Even Govt. is madeup of common man only. Majority of Babus, Poilce and all other sort of Govt. employees are common man only. So my perspective to monitor is that, "its monitor on all who lives in here, not the Govt in reality". Again, its not just the Cop's fault here, to be very clear so dont get offended with me :)

   I am neither against Nandan Nilekani nor against Anna. Infact I WONT call myself follower of Anna. I have my own way of combating. If you don't believe, just read my old blog: http://yagneshchawda.blogspot.com/2011/06/how-we-can-posibly-get-rid-of.html

   Every1 knows if Anna says "no one who has done a corruption in his life so far should support and come and join his movement", not even 5% mass should be there. Yes I am saying Five, and I think even that is too big number!! But can't we give all a second chance? Many of them must have been in a situation  where even if they are right, they have to do wrong stuffs just because of NO other alternative or-else they will be in even bigger trouble. Just try reading below article, you might get why am saying this:
http://www.facebook.com/notes/abhishek-rai/the-arvind-kejriwals-blog-a-must-read-incident/10150276202014033

 Currently If individual is right, but Not influential, s/he doesn't worth anything. But no matter if he is right/wrong, but if Influential "All is Well, rest all, go to Hell !!" Have we learn anything from Jessica-lal case?

    There is so much to talk and debate on this, but sadly we hardly get time to introspect it and discuss this with self only, forget abt doing it with others.

  So friends, as I always believe,
  1. Self monitoring is the key
  2. But, Monitor over is to make sure that self monitor keeps working.
  3. And they are are again cyclic in nature 1 <-> 2 ;)


  I am sure, you must have fallen asleep by now!! 
If yes, I acheived my goal, and if not, post/share this articles and let others feel the Joy of Sleep !!!  ;)
 

Sunday, July 24, 2011

Here are couple of new snaps my library....more avaialable @ http://www.facebook.com/media/set/?set=a.2240041719967.2130444.1215754687&l=44094ba8cf&type=1

                                         
                                          1.
                                          2.
                                           3. Baby kingfisher @ my society

Saturday, June 18, 2011

How we can possibly get rid of Courrption?


At one of the discussion thread where poeple were thinking if "Can Threat to Fast untoo death will get end to corruption or not". Here is my perspective to it. Although I have respect for Mr. Anna Hazare, so dont mis-interprete this blog.
      There is only One simple alternative, that is Change Ourselves.

          Perfect world never exists. We have to tame the level of evilness, thats it.

     Every corruption (big/small), is somehow touching aam-adami at some level for his involvement. eg. Govt. employees (most of them are aam-aadami only) had their small portion of interest in all corruption. If majority of them make sure that they dont get currupted, just image how difficult it will be for even big ministers to do corruption. They can start doing their job with sincerity.
 
      I m not just pointing at Govt. employees. We who are either in business, employees can file right Income taxes, thats the way we can make sure that we doing our job (of filing IT) correctly and ethically. Dont forget tat we can't blame others unless we are not clean.
 
      Its easy to get Power but difficult to digest it. We have Power to do some tax ka zhol, we and we do it, just imagine, Neta are having bigger powers with them, so they use it at that level. Its just the scale difference, nothing else.

   Also never forget "We get Govt, that we DESERVE. So first we have to make ourselve Deserving." Like rightly said, "Deserve b4 u Desire"

  Dont forget, we have very small memory, GoI is having a very small, simple but effective algorith for this problem:
1. We forget everything and we get bored of everything in just few days. We forget many important thing if India Wins World cup or Shilpa Shetty is getting married!!
2. GoI knows this very well and thats what they are exploiting.
3. Aam adami will join Mr. Anna for 2-3 or may be 5 times for his fastening. Every time Govt. will ask for some time or create some so called committe of bullshitters, who will again waste time.
4. Soon Mr.Anna will get frustu of them and again will go for fast. People will support him. Few from distance, few personally. but those are personally there with him, are also aam-adami, they also have to run their family. They can't keep skipping their business/ office and join Mr. Anna.
5. So atlast after some time Mr. Anna's streangth of mass with him with get shreded.

   I feel, Mr. Anna, and others whoc are also dreaming a future of less corrupted nation, should only spread word of mouth, and make poeple more awake about how being non-corrupted will make them and their future more happy then being corrupted and making fast money.

   Idea here is that, Janlok pal bill is NOT the solution at the end of the day. Solution is the attitude of  poeple, the mass attitude. Otherwise Janlokpal bill will also be just another "On-Paper law" in India like other thousands of Laws which are like "Toothless Tigers". An I wont regret for that as well, because we sadly would still deserve that!!!

Monday, April 4, 2011

Letter To resp. President Of India for Cricket WC-2011 logic of paying Cricketers

Hi Just sent a letter To resp. President Of India for Cricket WC-2011 logic of paying Cricketers. Here it goes.

Respected Madam,
     I am just another person living in India, and paying tax in the hope that it will be used for right cause & for right people. But recent Good incident also really make me feel sorry and low.
Yes, I am talking about Wining Cricket WorldCup. I am also fan of cricket and appreciate team for wining it. But got really sad when heard that public money is gonna be used for honoring them, that too with such a huge amount ( Rs. 1 Cr. per head )

    I am not against giving them honor/recognition. But that can be done in far better way and constructive way than its being decided. eg. with > 6 Cr. a new public school can be build or up gradation of Public hospitals can be done, which can bring joy to many lives. We can give the name of the cricketers for their honors if needed. We can give medal if needed. But giving away such a huge amount from public money that too to the cricketers where majority of them are not really in that under paid or something. Also lemme also tell you that I am also a big fan of cricket, so its not that I am writing this because I dont love this game and all.

    BCCI is NOT part of Govt. body, so do the players who are playing in it. Its like paying bonus to Employees of Pvt. Co. from Govt. treasury when that company is making profit..even that is also something that India will proud on when business will grow for that Indian Org. So should GoI declare bonus for them as well ?


    I seriously oppose these decisions. Aren't soldiers on border, Honest Police person on road etc. are way too bigger heroes than Cricket team ? Why we are not honoring them with such a great rewards? And why only to Cricket ? There are so many other sports heroes, who won Gold for us, dont we have proud on them ?
 

   I tried to send mail only to Resp. PM of India. I didn't find his email address. And sadly link http://pmindia.nic.in/write.htm to write him at his website  http://pmindia.nic.in/pmo.htm is also NOT  working.
So bothering you. Hope you will get some time out of your hectic schedule for Just another civilian. I expect a thoughtful time of yours in this issue, and hope you will take some decision which is in favor of country !!

Tuesday, March 29, 2011

Grails App Monitoring Plugin

   Just found a very good Grails Plugin for Grails App monitoring: http://grails.org/plugin/grails-melody
Worth giving a try !!

Understanding Grails GORM Secondary cache.

Hi,
  I always wanted to find out some detailed doc. which could explain me how GORM is managing Secondary cache (via Hibernate Obviously) for us. Obviously GORM gives us sugar coated way of defining Domains which are alowing us to call dynamic finders like find, findAll, finAllByXXX etc. and also allows us to fire Criteria, HQL etc. on that domain.
  You can get basics of this stuffs in grails doc. which is kind of good enough. But one thing I still feel is lacking the focus in Grails Doc. is the Secondary cache. Its not describing behavior of caching. Although part of it actually related to Hibernate, so thats why its not been docmented well there.

  Reason why I am writing this post is : http://grails.1312388.n4.nabble.com/Effect-of-Enabled-Hibernate-Level-2-cache-on-Domain-td3405253.html

Here are some basics that we should know atleast before going to further details.
  • There are dedicated regions for Domain cache and Query (standard query cache) cache. And one more special region called as "org.hibernate.cache.UpdateTimestampsCache". You will find enough docs online to understand what "org.hibernate.cache.UpdateTimestampsCache" is. So I wont go into its details for now.
  •  Dont forget that Hibernate Queries will get cached only if Secondary Query cache is enabled.
  •  Domain cache puts (a single row) Domain Instance in this cache region with key generated as follows: [Fully.Qualified.class.name:PrimaryKey]
  • Domain cache regions can be futher be customized to store a particular type of Domains only. This is to handle a situation where some domain cache has to expire soon or infrequently, or number of domain to be cached as to be different than other default cache (maxElementsInMemory) size.
  • Standard Query cache region is a seperate dedicated region, created automatically by Hibernate to store the results of the Cached Queries. It stores PK of all the rows that comes as result for the Query being fired. Its key is generated with following things: QueryStatement and Paramters map. This is because same query can be fired to get different result, for example to get paginated view, we keep on fireing same query, what we change is just the offset/start_index paramter in the query. And when results are got, we have to keep it seperate for each page in the cache.
  • If query cache is enabled in hibernate config, (datasources.groovy in our case), still to make sure that Dynamic finders caches it, we have to add cache:true in the params that we pass to the method. But list() method will not require it. It seems to assume put in the cache if query cacahe is enabled in hibernate config (datasource.groovy)
  • Mapping cache true declaration in domain allows domain instance to be part of Secondary cache regions which is dedicated for storing actual domain objects

Scenarios:
  1. Hibernate Cache + Query Cache is enabled, *NO* mapping of cache true in domain class, but cache : true specifieed in dynamic finder (findAll and findAllByxxx and criteria etc):
    •  If we fire dynamic finder like (findAll, findAllByxxx) with Query cache = true.
                i. Query resuls (PK) gets stored in cache. But Domain itself is not Cacheable because we have not mentioned mapping cache true in Domain class, Hibernate wont put it in the domain cache.  So if you hit same flow with same paramter again, Hibernate knows what all rows it requires as it knows PK of all rows in the results set for given query with specified paramters,
               So it fires individuals queries to DB for each expected rows with its PK. So assume that for the first time when Hiberate got 10 results for the given query and its params, if you fire same query with same params, hibernate will fire 10 (YES its 10) select SQL queries which is really * BAD *
    •  If we fire get(PK) method, and assume the PK we are already looking for NOT there in the Cache, it will get it from DB and CAN NOT put it in cache. So that every time you fire get(PK) it will get data from DB.
    •  If you did a insert/update anywhere in the table, whole Query Cache for that domain (of that type) will become invalid. Doesn't matter if Update has any changes in the Domain instance you are interested in or not. Its logically in-correct, but practically its too difficult to implement, and Hibernate guys have taken the obvious and simple route there to handle this situation by invalidating the cache. Domain cache for this cache is anyways ot having Domain o fthat type as cahe true mapping is not declared.
  2. Hibernate Cache + Query Cache is enabled, Mapping of cache true in domain class, but cache : true specified in dynamic finder (findAll and findAllByxxx and criteria etc):
    •  If we fire dynamic finder like (findAll, findAllByxxx) with Query cache = true. Query resuls (PK) gets stored in cache. So if you hit same flow with same paramter again, Hibernate knows what all rows it requires as it knows PK of all rows in the results set, it checks in secondary domain cache for PK, and it finds it there so no need to go to DB. * GOOD *
    • .If we fire get(PK) method, and assume the PK we are already looking for is already there in the Cache, it will get it from Cache, else will go to DB and put it in cache as well apart from returning to you. So that next time you fir get(PK) and cache is still valid, it will get data from cache.
    •  If Domain instance you want is already in Secondary cache, but you did a insert/update anywhere in the table, whole Cache (Domain Cache + Query Cache) for domain of that type will become invalid. Doesn't matter if Update has any changes in the Domain instance you are interested in or not. Its logically in-correct, but I think practically its too difficult to implement, and Hibernate guys have taken the obvious and simple route there to handle this situation by invalidating the cache.
    •  Dynamic finder's results are in Query cache. Suppose it returns 150 Rows. So Domain cache will have to store 150 domains in it. When you dont have enough space in memory to hold all those data, it should ideally overflow to disk store if enabled. This time your domain class will be stored in a disk file managed by eh-cache internally. You mention where to keep that files on disk in ehcache.xml file with <diskStore path="user.home/ehcache_data"/> node.

  I will keep adding more details as I will learn more of this.
All kind corrections or inputs are welcome !! Feel free to comment here or reply me on my email address as mentioned on facebook.

Friday, March 18, 2011

BSNL Broad band Pune Issue (resolved)

Hi,
  I got BSNL dataone broadband at Wakad, Pune just 2 days back. Since day one I started facing issue. Not that net is not working and all. But it used to stop loading page inbetween for many websites. And funniest part was that even facebook pages at times never used get loaded completely. I saw many js, image files are never getting loaded completely.

   Initially I thought some issue with DNS. But As half of the page is getting loaded from the same domain where download is stuck while loading is going on, its really not possible to blame DNS.

  This made me really crazy, my half a day was wasted because of this while I was developing an app using Facebook Javascript SDK. It never used to download http://connect.facebook.net/en_US/all.js, but facebook domain is always reachable with traceroute and normal page load during browsing.

  Issue got resolved final in my router configuration. I set TCP MTU=1300 and magic happened. Frankly speaking I still need to go through greater details about significance of this field, but for now this tweak is atleast allowing me to keep a smile on my face :)

Thursday, February 17, 2011

Grails Environment Checking: Better know a framework

 I took this from http://www.make-go-now.com/2009/03/19/grails-environment-checking-better-know-a-framework/

Grails Environment Checking: Better know a framework

Checking the environment that your Grails application is running.

Lets say you have some code that is dependent on the environment that it is running.

Here is one way to check it:

import org.codehaus.groovy.grails.commons.GrailsApplication
import grails.util.GrailsUtil

//check if production
if ( GrailsUtil.getEnvironment().equals(GrailsApplication.ENV_PRODUCTION)) ){...}

//check if development
if ( GrailsUtil.getEnvironment().equals(GrailsApplication.ENV_DEVELOPMENT)) ){...}

//check if testing
if ( GrailsUtil.getEnvironment().equals(GrailsApplication.ENV_TEST) ){...}


And here is how you can set the environment in your tests:

import org.codehaus.groovy.grails.commons.GrailsApplication
import grails.util.GrailsUtil

//set envionment to production
System.setProperty(GrailsApplication.ENVIRONMENT, GrailsApplication.ENV_PRODUCTION)

//set envionment to development
System.setProperty(GrailsApplication.ENVIRONMENT, GrailsApplication.ENV_DEVELOPMENT)

//set envionment to test
System.setProperty(GrailsApplication.ENVIRONMENT, GrailsApplication.ENV_TEST)

 

Friday, February 11, 2011

Creating a Auto Initialising Grails Service

  Many a times while developing a Grails based application, we come across a situation where we need to declare a service which needs to be initialized with some values in its Instance variable at runtime during Application bootup time.
  Grails Services are Singleton by default. Meaning that once initialised using its NEVER gonna get re-initialized again till the time app is running. This is expected behavior as well, just imagine how expensive it would be when Services are not singleton. Controllers of Grails are anyways NOT singleton as its scope is Request, so we can NOT really afford to have Service non-singleton as well !!
  Here is the way you can create such a Initialising Service:


import org.springframework.beans.factory.InitializingBean

class MyService implements InitializingBean {

    Long someVariableToBeInitialzed

    void afterPropertiesSet() {
            println "Initializing MyService...."

            /* Calculate dynamic value u want to set here for all the required instance Variables  */
            someVariableToBeInitialzed = ........
    }
}



Note:
   1. These Services beans will be initialised before "BootStrap,groovy" gets executed !! So beware that if you putting / settingup some data in bootstrap, that these service might use while initializing, you will be facing some issues like NPE etc. based on the type of data you setting-up in BootStrap.
   Solution:
      Although not a great and neat solution, but in such situations, rather than making service Initializable, you make a simple function in service and call it from Bootstrap after you have put the code to satisfy the dependencies for the service. You can refer to the service from BootStrap just like you do it in Controller. ie. by putting following line at the top of the class in BootStrap.groovy
    def xxxService


Why Grails/Groovy for your Next Web Application Development ???

Get answer to one of the most important Question you or your customer will ask to yourself :

Why Grails/Groovy for your Next Web Application Development ???

Monday, January 17, 2011

Maha Pakshi Ganana 2010 : Please participate

Maharashtra Pakshimitra
Admin. Office - 11, United Park, Markandi, Chiplun,
Dist. Ratnagiri - 415605.
Phone No. 02355 - 253030
Email - pakshimitra@gmail.com


“Maha Pakshi Ganana 2010”

Coordinator - Mr. Sharad Apte.

Guide lines for Census.
1)Fill in all column provided for basic information such as name of the organization etc.
2)Fill in coordinates and elevation if available.
3)Name of the location should accompany name of Taluka and District precisely. Mention name of the state if location falls in other state.
4)Date any day between 24/01/2010 to 31/01/2010 preferably on 24/01/2010 Time for census is fixed and it is 7.30 am to 9.30 am in the morning. Please repeat same location in late evening i.e. from 18.00 19.30 for nocturnal species. If census is organized in evening prefer time from 16.00 to 19.30(4pm to 7.30pm) for evening census focus on Nocturnal species. Depute some birder at roosting colonies.
5)Mention book referred for identification of species, to avoid confusion in English names please put plate No and species no in column provided.
6)Be careful while feeding count. Do not feel tentative figures like 20 to 30 or group.
7)Species identified but not includes in list provided, please add additional rows at the bottom and high light the row in Yellow.
8)Activity Breeding means:- Nest building, incubation, feeding chicks etc. If you seen any one of the said activity please fill it in column provided for.
9) Location and distance. Cover at least one km you may choose any location from busy city road to sanctuary. You may choose any small location like house campus, industry campus, garden etc.. Try to include students form local school college provide experts with every group and try to cover one or more location.
10) Fill the attached sheet and mail it to pakshimitra@gmail.com & cc to aptesharad@yahoo.co.in provided on same day.
11)If you have any problem to access Internet please make a proper list as per guidelines and send it by post to above address.

Please make necessary publication in local news paper.

If you have any queries please contact -

Mr. Sharad Apte - Email - aptesharad@yahoo.co.in or

Maharashtra Pakshimitra - Email - pakshimitra@gmail.com

More details available at:

Birds at my place if any one has got interest : http://www.facebook.com/album.php?aid=2099191&id=1215754687&l=3d7f2a685a

    Monday, January 3, 2011

    RabbitMQ

    Was going through some details of the RabbitMQ. Here are my notes based on the understanding I have got. Feel free to add your comments.

    • RabbitMQ is good in terms of Performance based on the reading that has been done from different blogs etc.
    • In general it has following main components
      • Broker : The RabbitMQ instance Running under ErLang node is called Broker. It contains all the Exchanges, Queues and Bindings.
      • Queue : Queue is the Endpoint where Consumer of the Message connects to the Broker. Broker fills the Queue based on the Exchange to which Queue is connected and Routing Rules (Bindings) defined.
      • Exchange : Its the one whom Publishers connects to while sending the Message out. Exchanges are attached with Queue using Bindings. Exchanges decouples the Queues and Producers so that single message can be routed to multiple places based on the Binding/Routing rules. There are muliplr types of Exchanges available :
        • Fanout : Message sent to Exchange will be sent to all the queues connected to the Exchange. Its kind of Broadcasting. Its like havong no routing key or "#" as routing key.
        • Direct : Message sent to Exchange will go to only that queue which has Exact Routing Key as Biding Key.
        • Topic : Message sent to Exchange will go to only those Queue which matches Routing Key and Binding key in a Regular expression form.
      • Binding Key : It defines which message will be put in which queue when it arrives to Exchange. Its defined at the Server end.
      • Routing Key : It defines the message destination queue routing which is patten matched or compared as it is based on the Exchange type.
    • It supports In-memory and Persistent Message Queues. 
      • Non-Durable : Its default behavior. Upon Broker crash/restart nothing will be recovered. All Exchange. Queues, Bindings info will be lost.
      • Durable : Exchange, Queues, Bindings meta-data is stored so that post crash/restart, it will be recreated. But data will be lost.
      • Persistent : If Broker node crashes, all Exchange, Queues, Bindings and data in the queue are recovered upon the Broker restart.
    • RabbitMQ supports Clustering.
    • But clustering concept is not allowing Data federation. It just does he federation/replication of Meta-Data of Exchanges, Queues and Bindings. Queue data is always Local to the Node only. i.e. Data will never get replicated across the Cluster nodes to have High Availability. Strangely, but, in-short we can say RabbitMQ focuses on on the Scalability rather than Availability. Following are some links which highlights this points:
                        http://www.rabbitmq.com/faq.html#does-clustering-replicate-messages-to-both-servers
                        http://www.rabbitmq.com/faq.html#replication-scope
                        http://dev.rabbitmq.com/irclog/index.php?date=2008-08-27 : Read it around "[16:39] can someone explain the current limitations of the high avaliabilty and performance clustering using erlang's OTP? I have read a powerpoint that says what is above?"
                       http://lists.rabbitmq.com/pipermail/rabbitmq-discuss/2009-July/004234.html