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10 Newer Entries Showing entries 31 to 40 of 407 10 Older Entries

Displaying posts with tag: postgresql (reset)

Comparing open source GIS implementations
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In my quest to understand spatial GIS functionality, I have come to the ultimate goal: evaluation the actual database products themselves.

PostgreSQL / PostGIS

PostGIS is a variant of PostgreSQL with spatial extensions. The main reason for maintaining the GIS feature set outside of PostgreSQL proper seems to be licensing: the spatial extensions are LGPL GPL licensed.

PostGIS is widely recognized as the most mature and feature-rich GIS implementation for SQL databases (and perhaps any database), matched only by the costly Spatial extension for the Oracle Enterprise database. (See comparisons in the links below.)

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The OpenGIS standard
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While the underlying index should be opaque to the user of a DBMS with spatial features, the API used to define spatial types and operate on them is of course more visible. The relevant standard in this space is often referred to as "OpenGIS", however the Open Geospatial Consortium in fact defines a long list of standards. The standard relevant to SQL databases is known more precisely as "OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 2: SQL option" aka "Simple feature access".

It is not meaningful to recite the standard at length in my blog, my focus is instead on actual implementations that I will blog about later. …

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Spatial data structures
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I work for a company that is the leading supplier of automotive maps, and wants to be the leading supplier of online maps. So it was only a matter of time that I needed to learn more about how spatial extensions work in different open source databases. Let's start from the beginning, understanding various spatial data structures that are used in implementations...

Links are provided to Wikipedia articles - which are both comprehensive, yet easy to understand - for those who want to get a deeper understanding of each structure. All Wikipedia articles on spatial indexes are listed here: …

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XA Transactions between TokuDB and InnoDB
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The recently released TokuDB brings many features. One of those features is support for XA Transactions. InnoDB already has support for XA Transactions.

XA Transactions are transactions which span multiple databases and or applications. XA Transactions use 2-phase commit, which is also the same method which MySQL Cluster uses.

Internal XA Transactions are used to keep the binary log and InnoDB in sync.

Demo 1: XA Transaction on 1 node:

mysql55-tokudb6> XA START 'demo01';
Query OK, 0 rows affected (0.00 sec)

mysql55-tokudb6> INSERT INTO xatest(name) VALUES('demo01'); …









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Log Buffer #268, A Carnival of the Vanities for DBAs
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Log Buffer Editions are marching along, and this Log Buffer #268 is once again all about Oracle, MySQL, and SQLServer plus some peeks at some of other glittering database technologies like PostgreSQL and DB2. Sit back and enjoy. Oracle: Martin has produced another scenario based blog post about Shrinking Tables to Aid Full Scans. What [...]

Disproving the CAP Theorem
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Since the famous conjecture by Eric Brewer and proof by Nancy Lynch et al., CAP has given the world countless learned discussions about distributed systems and many a well-funded start-up.  Yet who truly understands what CAP means?  Even a cursory survey of the blogosphere shows profound disagreement about the meaning of terms like CP, AP, and CA in real systems.  Those who disagree on CAP include some of the most illustrious personages of the …

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Black-Box Performance Analysis with TCP Traffic
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This is a cross-post from the MySQL Performance Blog. I thought it would be interesting to users of PostgreSQL, Redis, Memcached, and $system-of-interest as well.

For about the past year I’ve been formulating a series of tools and practices that can provide deep insight into system performance simply by looking at TCP packet headers, and when they arrive and depart from a system. This works for MySQL as well as a lot of other types of systems, because it doesn’t require any of the contents of the …

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On datatypes, domains and why I think it's time we reconsidered
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What's in a datatype then? A MySQL SMALLINT? A C int? An Oracle BLOB? One thing is for sure, they are not very well standardized, not even within the same environment, and much less so across them. And what does it means, really? When should I use a BLOB, when a BINARY VARCHAR and when to use a long long?

A datatype defines many attributes:

  • What data I can store in it: Only numbers? Printable alaphanumeric characters? Unicode? Binary data? An object?
  • What I can do with a value of that particular type and how does it behave? Can I concatenate two values? Add them (that is NOT the same as …



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Continuent Partners With VNC To Collaborate in DACH
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Continuent is increasing its presence in Europe to offer our solutions and services for the open source database business sector in the region. VNC is Continuent's new partner in Germany, Austria and Switzerland (DACH). Read the entire press release here.Continuent and VNC are hosting a live webcast demonstrating advanced MySQL and PostgreSQL replication and clustering with Continuent Tungsten

MySQL and PostgreSQL Cloud Offerings – linux.conf.au 2012 miniconf talk by myself and Selena
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Selena and I gave a talk on the various issues of running databases “in the cloud” at the recent linux.conf.au in Ballarat. Video is up, embedded below:

10 Newer Entries Showing entries 31 to 40 of 407 10 Older Entries

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