There is a new release of ManagedEsent on Codeplex. There are some new APIs, bugfixes and performance improvements. The PersistentDictionary class now supports LINQ -- it can examine a query and retrieve only matching records from the database. Some...

Multivalued columns can be very useful for simplifying data schema and improving performance, but they can be complex to use (they also make Data Normalization geeks feel uneasy). I put a multi-value tutorial up on the ManagedEsent wiki. It uses the managed...

Cameron Taggart has a blog entry on using ManagedEsent from F#: http://blog.ctaggart.com/2010/02/microsofts-extensible-storage-engine.html The ESENT programming model centers around a database cursor (JET_TABLEID). The cursor is located on a record...

There is a new release of ManagedEsent on Codeplex . There are some new APIs, constants for the new Windows 7 ESENT features, bugfixes and performance improvements. There is also a new Esent.Collections.dll which contains a PersistentDictionary generic...

A quick look at some of the new features that are available in the Windows 7 version of ESENT. You'll need esent.h from the Windows 7 SDK to see these definitions: 1. Column Compression Columns of type JET_coltypLongBinary and JET_coltypLongText...

(Continuing from the post on implementing the Visitor pattern in C# 4.0) A virtual method is polymorphic in one dimension (the runtime class of the object the method is attached to). Multimethods (multiple dispatch) are polymorphic in multiple dimensions...

A lot of the talk around the new dynamic keyword in C# 4.0 (available in the beta of Visual Studio 2010 ) is around interaction with external components (dynamic languages, HTML DOM, COM) but I'm most excited about being able to stragetically add dynamic...

Microsoft has released Kobe , "a getting started resource kit for planning, architecting, and implementing Web 2.0 applications and services using the Microsoft Platform" and a lot of the response has been quite critical ( Ayende , Karl Seguin ). While...

(I saw a link to this from the Wikipedia entry on esent) A company called iiobo has released a C++ toolkit for using esent (I'm guessing they developed it for internal use). I haven't looked at the code, but their website says that they have: "C...

Version 1.2 of the ManagedEsent interop layer for the ESENT database engine is now available on CodePlex. The three most useful additions here are: JetEscrowUpdate JetIntersectIndexes Helper functions to set/retrieve columns as DateTime ...

On our internal mailing list a user asked "When I retrieve a column of type JET_coltypBit that is set to true, why do I get 0xFF and not 0x1"? My co-worker Ketan had to reach deep into his memory for the answer :-) In the very old days, the...

(or is "xxx considered harmful" completely worn out as a meme?) I believe that, in general, people should avoid unsigned variables, even when dealing with quantities which should only be positive. I have three major problems with unsigned variables...

A JET_COLUMNID identifies a column inside of a table (it is actually an index into an internal per-table array of column definition structures). The database meta-data provides a mapping from column name to columnid. The mapping of column names to columnids...

When an assert goes off what does it mean? In the codebases I work in, a failing assert doesn't always indicate that the code is about to fail. There actually are several conditions that we want to check with asserts. The first three are from Meyer...

Fluent interfaces are a nice way of building up an API which reads very nicely. Chaining methods together is often a big part of fluent interfaces, but doing so isn't always as straightforward as it looks, especially for configuration objects. Suppose...

Counting the number of records in a table can be extremely expensive, as it requires reading all the database pages off disk. It is possible to get a reasonably accurate estimate the number of records in a table by using the JetGetRecordPosition API....

I've wanted to be able to use Esent as a simple, fast, reliable and persistent key/value store. The Python standard libraries contain that kind of functionality in the *dbm modules. I've been working on providing identical functionality layered on top...

I was working on some old code that had a structure that looked like this struct Foo { bool fOptionEnabled; }; Tons of places in the code would check to see if the option was enabled, and do something based on it. The change I needed to make required...

I confess that, for some years now, I've wondered what the managed equivalent of memcmp() was, usually when I wanted to compare two byte arrays for equality. It turns out that Linq provides a SequenceEquals() extension method which does exactly what I...

Inserting a record into a table doesn't change the location of the JET_TABLEID used to insert the record. At one level this makes sense because a JET_TABLEID is an iterator on a table and inserting a record into a table shouldn't change the position of...

Besides providing lots of great input on the new managed layer, Ayende Rahien has found time to start using esent in a new project to store JSON (JavaScript Object Notation) objects . Esent is an important part of the Windows Server story, providing...

I just published the first release of the Esent .NET managed interface on Codeplex. http://www.codeplex.com/ManagedEsent This is an interop layer can be used to write managed applications that use esent. There is a straightforward translation of...

I was reading a performance whitepaper about another embedded database engine and decided to write a program with similar parameters to get an idea of how quickly ESENT would run on my laptop. First, the warnings I ran the test under real-world...

(All links go to the named Wikipedia article) ESE/ESENT is an embedded database engine providing ACID (Atomic, Consistent, Isolated, Durable) transactions with snapshot isolation using multi-version concurrency control and the ARIES variant of write...

Although the ESENT API has been available in the Windows SDK for several years, I don't think enough people are aware of it. I have a blog post on the Windows SDK blog that gives an overview of ESENT and has a tiny 'hello world' program. http://blogs...