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Note: All the posts are based on practical approach avoiding lengthy theory. All have been tested on some development servers. Please don’t test any post on production servers until you are sure.

Tuesday, March 25, 2014

Fact Sheet - Hekaton - TimesTen

Upon the request of one of my friend, below is the quickly prepared fact sheet for Microsoft's Hekaton and Oracle's TimesTen, will be updated more soon.

Uses Commodity Hardware
Uses Commodity Hardware
New database engine built in to MS SQLServer
Deployed in the application tier as an embedded or standalone database.  SQL access does not incur any network or IPC overhead.
Only Windows Platform
Available for Linux,AIX,Solaris,Windows etc
Lock free (row versions)

Native compiled stored procedures

Transaction log optimization (block writes, no undo)

Index optimization (Only in-memory, Not persisted to disk, no tx logging)

No TempDB

Max memory supported 512GB
No Limit (Oracle has client with 2TB DB)
Failure to allocate memory will fail transactional workload at run-time

In Memory Table requires special filestream filegroup
No special requirement
In datafiles Data written only upon Tx commit
Checkpointing is available
deleted records (updates are an insert/delete pair) are stored in Delta files

Row Versions which are no longer referenced are garbage collected.

You cannot have partial in-memory table, it has to fit in-memory 100%, forever
Instead of caching the whole database, a subset of the database tables, columns and rows can be cached in TimesTen. You can define a dynamic cache, where the data from the Oracle tables are loaded on demand.
Row Sizes can’t be larger than 8060 bytes (incl. Variable Length Columns)
The same database design techniques that are used for RDBMS can also be used for TimesTen.
LOB, XML Data Types are not supported
No Foreign Key and Check Constraints
No DML Triggers
No ALTER Table (Need to recreate table)
Cache tables are managed like regular relational database tables within the TimesTen
No diff backups

Indexes are rebuilt (consider startup time)

Running out of memory issues

Native compiled stored procedures - Compiled in to C or dll

Native compiled stored procedures - can only access In-memory tables

Native compiled stored procedures - not all T-SQL constructs and functions supported

Native compiled stored procedures - no alter procedure – must drop and recreate

Provides full generality and functionality of a relational database, the transparent maintenance of cache consistency with the Oracle Database, and the real-time performance of an in-memory database.

Oracle In-Memory Database Cache is a database option for the Oracle 12c and Oracle 11database. 

responses to SQL requests in microseconds - 1.78 microseconds (0.00178 ms) for a SQL SELECT statement and 7 microseconds (0.007 ms) for a SQL UPDATE statement.

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