Practical Time Series Tools - Time Series Databases - page 39

a high degree of schema flexibility. The Open TSDB developers have used this to their ad-
vantage by starting with something like a star schema design, moving almost immediately to
a wide table design, and later extending it with a compressor function to convert wide rows
into blobs. (The concepts behind these approaches was explained in Chapter 3 . ) As the blob
architecture was introduced, the default time window was increased from the original 60
seconds to a more blob-friendly one hour in length.
As it stands, however, Open TSDB also suffers a bit from its history and will not support ex-
tremely high data rates. This limitation is largely caused by the fact that data is only com-
pacted into the performance-friendly blob format after it has already been inserted into the
database in the performance-unfriendly wide table format.
The default user interface of Open TSDB is also not suitable for most users, especially those
whose expectations have been raised by commercial quality dashboarding and reporting
products. Happily, the open source Grafana project described later in this chapter now
provides a user interface with a much higher level of polish. Notably, Grafana can display
data from, among other things, an Open TSDB instance.
Overall, Open TSDB plus HBase or MapR-DB make an interesting core storage engine. Ad-
ding on Grafana gives users the necessary user interface with a bit of sizzle. All that is fur-
ther needed to bring the system up to top performance is to add a high-speed turbo-mode
data ingestion framework and the ability to script analyses of data stored in the database. We
also show how to do both of these things in this chapter.
We focus on Open TSDB in this chapter because it has an internal data architecture that sup-
ports very high-performance data recording. If you don't need high data rates, the InfluxDB
project may be a good alternative for your needs. InfluxDB provides a very nice query lan-
guage, the ability to have standing queries, and a nice out-of-the-box interface. Grafana can
interface with either Influx DB or Open TSDB. Let's take a look in more detail about how
native Open TSDB works before introducing the high-performance, direct blob extensions
contributed by MapR.
Architecture of Open TSDB
In Chapter 3 we described the options to build a time series database with a wide table design
based on loading data point by point or by pulling data from the table and using a back-
ground blob maker to compress data and reload blobs to the storage tier, resulting in hybrid
style tables (wide row + blob). These two options are what basic Open TSDB provides. The