Home > Articles > Web Development

This chapter is from the book

Comparing SimpleDB to Other Products and Services

Numerous new types of products and services are now available or will soon be available in the database/data service space. Some of these are similar to SimpleDB, and others are tangential. A few of them are listed here, along with a brief description and comparison to SimpleDB.

Windows Azure Platform

The Windows Azure Platform is Microsoft's entry into the cloud-computing fray. Azure defines a raft of service offerings that includes virtual computing, cloud storage, and reliable message queuing. Most of these services are counterparts to Amazon services. At the time of this writing, the Azure services are available as a Community Technology Preview. To date, Microsoft has been struggling to gain its footing in the cloud services arena.

There have been numerous, somewhat confusing, changes in product direction and product naming. Although Microsoft's cloud platform has been lagging behind AWS a bit, it seems that customer feedback is driving the recent Azure changes. There is every reason to suspect that once Azure becomes generally available, it will be a solid alternative to AWS.

Among the services falling under the Azure umbrella, there is one (currently) named Windows Azure Table. Azure Table is a distributed key-value store with explicit support for partitioning across storage nodes. It is designed for scalability and is in many ways similar to SimpleDB. The following is a list of similarities between Azure Table and SimpleDB:

  • All access to the service is in the form of web requests. As a result, any programming language can be used.
  • Requests are authenticated with encrypted signatures.
  • Consistency is loosened to some degree.
  • Unique primary keys are required for each data entity.
  • Data within each entity is stored as a set of properties, each of which is a name-value pair.
  • There is a limit of 256 properties per entity.
  • A flexible schema allows different entities to have different properties.
  • There is a limit on how much data can be stored in each entity.
  • The number of entities you can get back from a query is limited and a query continuation token must be used to get the next page of results.
  • Service versioning is in place so older versions of the service API can still be used after new versions are rolled out.
  • Scalability is achieved through the horizontal partitioning of data.

There are also differences between the services, as listed here:

  • Azure Table uses a composite key comprised of a partition key followed by a row key, whereas SimpleDB uses a single item name.
  • Azure Table keeps all data with the same partition key on a single storage node. Entities with different partition keys may be automatically spread across hundreds of storage nodes to achieve scalability. With SimpleDB, items must be explicitly placed into multiple domains to get horizontal scaling.
  • The only index in Azure Table is based on the composite key. Any properties you want to query or sort must be included as part of the partition key or row key. In contrast, SimpleDB creates an index for each attribute name, and a SQL-like query language allows query and sort on any attribute.
  • To resolve conflicts resulting from concurrent updates with Azure Table, you have a choice of either last-write-wins or resolving on the client. With SimpleDB, last-write-wins is the only option.
  • Transactions are supported in Azure Table at the entity level as well as for entity groups with the same partition key. SimpleDB applies updates atomically only within the scope of a single item.

Windows Azure Table overall is very SimpleDB-like, with some significant differences in the scalability approach. Neither service has reached maturity yet, so we may still see enhancements aimed at easing the transition from relational databases.

It is worth noting that Microsoft also has another database service in the Windows Azure fold. Microsoft SQL Azure is a cloud database service with full replication across physical servers, transparent automated backups, and support for the full relational data model. This technology is based on SQL Server, and it includes support for T-SQL, stored procedures, views, and indexes. This service is intended to enable direct porting of existing SQL-based applications to the Microsoft cloud.

Google App Engine

App Engine is a service offered by Google that lets you run web applications, written in Java or Python, on Google's infrastructure. As an application-hosting platform, App Engine includes many non-database functions, but the App Engine data store has similarities to SimpleDB. The non-database functions include a number of different services, all of which are available via API calls. The APIs include service calls to Memcached, email, XMPP, and URL fetching.

App Engine includes an API for data storage based on Google Big Table and in some ways is comparable to SimpleDB. Although Big Table is not directly accessible to App Engine applications, there is support in the data store API for a number of features not available in SimpleDB. These features include data relations, object mapping, transactions, and a user-defined index for each query.

App Engine also has a number of restrictions, some of which are similar to SimpleDB restrictions, like query run time. By default, the App Engine data store is strongly consistent. Once a transaction commits, all subsequent reads will reflect the changes in that transaction. It also means that if the primary storage node you are using goes down, App Engine will fail any update attempts you make until a suitable replacement takes over. To alleviate this issue, App Engine has recently added support for the same type of eventual consistency that SimpleDB has had all along. This move in the direction of SimpleDB gives App Engine apps the same ability as SimpleDB apps to run with strong consistency with option to fall back on eventual consistency to continue with a degraded level of service.

Apache CouchDB

Apache CouchDB is a document database where a self-contained document with metadata is the basic unit of data. CouchDB documents, like SimpleDB items, consist of a group of named fields. Each document has a unique ID in the same way that each SimpleDB item has a unique item name. CouchDB does not use a schema to define or validate documents. Different types of documents can be stored in the same database. For querying, CouchDB uses a system of JavaScript views and map-reduce. The loosely structured data in CouchDB documents is similar to SimpleDB data but does not place limits on the amount of data you can store in each document or on the size of the data fields.

CouchDB is an open-source product that you install and manage yourself. It allows distributed replication among peer servers and has full support for robust clustering. CouchDB was designed from the start to handle high levels of concurrency and to maintain high levels of availability. It seeks to solve many of the same problems as SimpleDB, but from the standpoint of an open-source product offering rather than a pay-as-you-go service.

Dynamo-Like Products

Amazon Dynamo is a data store used internally within Amazon that is not available to the public. Amazon has published information about Dynamo that includes design goals, run-time characteristics, and examples of how it is used. From the published information, we know that SimpleDB has some things in common with Dynamo, most notably the eventual consistency.

Since the publication of Dynamo information, a number of distributed key-value stores have been developed that are in the same vein as Dynamo. Three open-source products that fit into this category are Project Voldemort, Dynomite, and Cassandra. Each of these projects takes a different approach to the technology, but when you compare them to SimpleDB, they generally fall into the same category. They give you a chance to have highly available key-value access distributed across machines. You get more control over the servers and the implementation that comes with the maintenance cost of managing the setup and the machines. If you are looking for something in this class of data storage, SimpleDB is a likely touch-free hosted option, and these projects are hands-on self-hosted alternatives.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020