Shantanu's Blog

Database Consultant

February 19, 2012


Zmanda Quick Backup

Zmanda quick backup is a useful tool to take and schedule incremental backups. It has more features than the the built-in tool mysqldump.

# download and install ZRM:
rpm -iUh *

# configuration parameters for ZRM Tools:
cd /etc/mysql-zrm
mkdir dailyrun
cp mysql-zrm.conf dailyrun/
cd dailyrun
vi mysql-zrm.conf

# change the configuration file on mysql-zrm.conf:

# taking the backup:
mysql-zrm-scheduler --now --backup-set dailyrun

# restoring the full backup:
mysql-zrm --action restore --backup-set fullbackup --source-directory /var/lib/mysql-zrm/dailyrun/20120219074625 --databases "test"

# Schedules a daily backup at 1am everyday using cron:
mysql-zrm-scheduler --add --interval daily --start 01:00 --backup-level 0 --backup-set dailyrun
mysql-zrm-scheduler --query

# crontab -l
0 1 * * * /usr/bin/zrm-pre-scheduler --action backup --backup-set dailyrun --backup-level 0 --interval daily
0 4 * * * /usr/bin/mysql-zrm --action purge

# for more options for mysq-zrm are as follows:
mysql-zrm --action --help

# If you get the following error, you will have to install perl DBD mysql module.
# the DBD::mysql perl module hasn't been fully installed

tar xvf DBD-mysql-4.020.tar.gz
cd DBD-mysql-4.020
perl Makefile.PL
make install

# Other useful ZRM commands:
mysql-zrm-reporter --where backup-set=dailyrun --show backup-performance-info
mysql-zrm-reporter --where backup-set=dailyrun --show restore-info
mysql-zrm --action verify-backup --backup-set dailyrun

# backup report:

cat /var/lib/mysql-zrm/dailyrun/20120219074625/index

mysql-zrm-version=ZRM for MySQL Community Edition - version 2.2.0
logical-databases=performance_schema test
backup-size=0.87 MB
backup-status=Backup succeeded

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February 14, 2012


Improving restoration speed of dumped data

Let's assume we want to take the backup of a big table "customer" that has 1 primary key and 2 secondary keys i.e. name and city. When we insert records in this table, both the indexes will get updated. If we add these indexes after inserting all the records, we can restore the data much faster. This was added as feature request...

I have created a stand-alone mysqldump utility that will add the keys after generating all "insert into" statements as shown below.

# ./mysqldump.static test customer --keys-last

CREATE TABLE `customer` (
`name` varchar(100) DEFAULT NULL,
`city` varchar(200) DEFAULT NULL,
KEY `name` (`name`,`city`),
KEY `city` (`city`)

ALTER TABLE `customer` DROP KEY `name` , DROP KEY `city` ;
INSERT INTO `customer` VALUES (1,'Amar','mumbai'),(2,'Akbar','delhi');
ALTER TABLE `customer` ADD KEY `name` (`name`,`city`), ADD KEY `city` (`city`);

As you can see from the above example, the "keys-last" option will force the dump utility to drop the indexes first and then recreate them after all inserts. This will drastically improve the time it takes to restore data from a dumped file. The time saved will depend upon the number of rows and indexes, but overall 20% gain is something that can be achieved very easily!

The utility can be downloaded from...

percona seems to have done this long back using the option "--innodb-optimize-keys".

It applies to InnoDB tables only.

More info...

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February 11, 2012


aws command prompt

In order to use S3 and ec2 Simple Command-Line Access to AWS we need to install an utility:

Here are the steps to follow. This will help to manage the buckets using command prompt and there is no need to use the web console.

curl -o aws
chmod +x aws
vi ~/.awssecret
(type key and secret key)
chmod go-rwx ~/.awssecret

perl aws --install

s3mkdir shantanuo_BUCKET_NAME
s3put shantanuo_BUCKET_NAME test.txt
s3ls shantanuo_BUCKET_NAME
s3get shantanuo_BUCKET_NAME/test.txt
s3delete shantanuo_BUCKET_NAME/test.txt
s3delete shantanuo_BUCKET_NAME

ec2din --simple



AWS product stack

Here is the list of tabs those I can see when I log in. I am not impressed by most of them, but EC2, RDS and DynamoDB will prove miracles in the hosting world.

Elastic Beanstalk: makes it even easier to deploy and manage scalable applications on the AWS cloud, while retaining the ability to control the underlying resources.

S3: Buckets to store data that can also be shared on the net.

EC2: Start or terminate different type of virtual servers.

VPC: Virtual Private cloud for your EC2 resources.

CloudWatch: monitors operational and performance metrics for your AWS cloud resources and applications.

Elastic MapReduce: Creating a job flow to process your data in a simple and quick way.

CloudFront: Allow public access to your S3 buckets

CloudFormation: pre installed Drupal, Joomla or wordpress

RDS: hosted Relational Database Systems like MySQL / Oracle

ElastiCache: a web service that makes it easier to launch, manage, and scale a distributed in-memory cache in the cloud.

SQS: Simple Queue Service offers a reliable, highly scalable, hosted queue for storing messages as they travel between applications.

IAM: Identity and Access Management (IAM) enables you to manage Users, groups and permissions within your AWS account.

SNS: Simple Notification Service (SNS) is a web service that makes it easy to set up, operate, and send notifications in the cloud.

SES: Simple Email Service (SES) allows you to send emails.

Route 53: Allows you to manage your domain name and sub-domains.

DynamoDB: a fully managed non-relational fast database service that comes with seamless scalability.

Storage Gateway: An on-premises virtual appliance that provides seamless and secure integration between your appliances and AWS's storage infrastructure.


February 10, 2012


Import, Export and SQLize DynamoDB

You can use Hive to export data from DynamoDB to S3 bucket using Hadoop

In order to use hadoop, you need Elastic MapReduce instance. Click on "Create New Job Flow" and use defauls to create a new job called "My Job Flow". You will now get the Master Public DNS Name to connect to using "hadoop" as username. Once connected, type "hive" to get the command prompt where you can link to DynamoDB table.

hive> CREATE EXTERNAL TABLE hivereply (col1 string, col2 string, col3 string, col4 string)
STORED BY 'org.apache.hadoop.hive.dynamodb.DynamoDBStorageHandler'
TBLPROPERTIES ("" = "reply",
"dynamodb.column.mapping" = "col1:Id,col2:ReplyDateTime,col3:Message,col4:PostedBy");

You can now use the table hivereply just like any other MySQL table. For e.g.
hive> select * from hivereply where col2 = '2012-01-31 23:09:46';

Amazon DynamoDB#DynamoDB Thread 2 2012-01-31 23:09:46 null

You can call the INSERT OVERWRITE command to write the data to an external directory. You can use this to create an archive of your Amazon DynamoDB data in Amazon S3.

hive> INSERT OVERWRITE DIRECTORY 's3://php-sdk-getting-started-aki-19/' SELECT * FROM hiveTableName;

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Using Comparision Operator in dynamodb

If you want to query the data, you need to index it on Range key. For e.g. in the following "reply" table we have a primary key that is combination of Hash key and a Range key. Range key is nothing but the timestamp as on the reply was received. We can write a query that will return all the replies those are older than 7 days.
In this case the column "ReplyDateTime" column is indexed and we can use Comparison Operator.

require_once 'sdk.class.php';

$ten_days_ago = date('Y-m-d H:i:s', strtotime("-10 days"));

// Instantiate the class
$dynamodb = new AmazonDynamoDB();

$add_response = $dynamodb->put_item(array(
'TableName' => 'reply',
'Item' => array(
'Id' => array( AmazonDynamoDB::TYPE_STRING => 'Amazon DynamoDB#DynamoDB Thread 2' ), // Hash Key
'ReplyDateTime' => array( AmazonDynamoDB::TYPE_STRING => $ten_days_ago ), // Range Key
'Message' => array( AmazonDynamoDB::TYPE_STRING => 'DynamoDB Thread 2 Reply 1 text' ),
'PostedBy' => array( AmazonDynamoDB::TYPE_STRING => 'User A' ),

// Success?

$seven_days_ago = date('Y-m-d H:i:s', strtotime("-7 days"));

$response = $dynamodb->query(array(
'TableName' => 'reply',
'HashKeyValue' => array( AmazonDynamoDB::TYPE_STRING => 'Amazon DynamoDB#DynamoDB Thread 2' ),
// optional parameters
'AttributesToGet' => array( 'ReplyDateTime', 'Message', 'PostedBy' ),
'ConsistentRead' => true,
'RangeKeyCondition' => array(
'ComparisonOperator' => AmazonDynamoDB::CONDITION_LESS_THAN_OR_EQUAL,
'AttributeValueList' => array(
array( AmazonDynamoDB::TYPE_STRING => $seven_days_ago )

// 200 response indicates Success

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NoSQL support by AWS

Click on "Create Table" button on "DynamoDB" tab while using AWS web Management Console.

Type table name "testme1" and choose Number as Primary Key Type. Hash attribute name can be "Id". Assuming that you have correctly installed AWS SDK, the following PHP code should add a key - value to the table testme1 table.

require_once 'sdk.class.php';

// Instantiate the class
$dynamodb = new AmazonDynamoDB();

$add_response = $dynamodb->put_item(array(
'TableName' => 'reply',
'Item' => array(
'Id' => array( AmazonDynamoDB::TYPE_STRING => 'Amazon DynamoDB#DynamoDB Thread 2' ), // Hash Key
'ReplyDateTime' => array( AmazonDynamoDB::TYPE_STRING => '2012-01-31 23:28:40' ), // Range Key
'Message' => array( AmazonDynamoDB::TYPE_STRING => 'DynamoDB Thread 2 Reply 1 text' ),
'PostedBy' => array( AmazonDynamoDB::TYPE_STRING => 'User A' ),

// Success?


get item is obviously similar to put_item as shown above:

$get_response = $dynamodb->get_item(array(
'TableName' => 'reply',
'Key' => array(
'HashKeyElement' => array( AmazonDynamoDB::TYPE_STRING => 'Amazon DynamoDB#DynamoDB Thread 2' )


In order to drop the table, use the following:

$delete_response = $dynamodb->delete_table(array(
'TableName' => 'reply'


The following code will create a table called "reply":

$create_response = $dynamodb->create_table(array(
'TableName' => 'reply',
'KeySchema' => array(
'HashKeyElement' => array(
'AttributeName' => 'Id',
'AttributeType' => AmazonDynamoDB::TYPE_STRING
'RangeKeyElement' => array(
'AttributeName' => 'ReplyDateTime',
'AttributeType' => AmazonDynamoDB::TYPE_STRING
'ProvisionedThroughput' => array(
'ReadCapacityUnits' => 10,
'WriteCapacityUnits' => 5


Here are 3 easy steps you may need to follow if you have not already downloaded and configured Software Development kit from Amazon.

# Download AWS SDK for PHP
svn co AWSSDKforPHP

# copy sample to config file

# add your actual key and secret found on "security credentials" page that can be found here...


'key' => 'ABCD',
'secret' => 'XYZ',
'default_cache_config' => '/tmp/',

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