eedaaecc46
This patch allows using custom origin's in CAGGs, for instance:
time_bucket_ng('7 days', day, '2000-01-03' :: date) AS bucket
For weekly buckets this allows the user to choose what should be considered
the beginning of the week - Sunday or Monday. Also by shifting the origin
one second forward or backward user can tweak the inclusiveness of the
buckets.
This works for date's, timestamp's and timestamptz's. The bucket size is
considered variable-sized in all these cases. CAGGs on top of distributed
hypertables, compressed hypertables and compressed distributed hypertables
are supported as well.
Additionally, this patch does several small refactorings. Firstly, it makes
sure that experimental features of CAGGs will be tested in both Debug and
Release builds. This was previously overlooked. Secondly, it renames the tests
so that a person who is working on experimental features in CAGGs will be able
to easily execute all the related tests: `TESTS='exp_cagg_*' make installcheck`
Last but not least the patch refactors is_valid_bucketing_function() and
renames it to function_allowed_in_cagg_definition(). The reason to do it in
this patch is that otherwise, the logic of the function gets rather confusing
which complicates code review.
fix
| Linux/macOS | Linux i386 | Windows | Coverity | Code Coverage |
|---|---|---|---|---|
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TimescaleDB
TimescaleDB is an open-source database designed to make SQL scalable for time-series data. It is engineered up from PostgreSQL and packaged as a PostgreSQL extension, providing automatic partitioning across time and space (partitioning key), as well as full SQL support.
If you prefer not to install or administer your instance of TimescaleDB, hosted versions of TimescaleDB are available in the cloud of your choice (pay-as-you-go, with a free trial to start).
To determine which option is best for you, see Timescale Products for more information about our Apache-2 version, TimescaleDB Community (self-hosted), and Timescale Cloud (hosted), including: feature comparisons, FAQ, documentation, and support.
Below is an introduction to TimescaleDB. For more information, please check out these other resources:
For reference and clarity, all code files in this repository reference
licensing in their header (either the Apache-2-open-source license
or Timescale License (TSL)
). Apache-2 licensed binaries can be built by passing -DAPACHE_ONLY=1 to bootstrap.
(To build TimescaleDB from source, see instructions in Building from source.)
Using TimescaleDB
TimescaleDB scales PostgreSQL for time-series data via automatic partitioning across time and space (partitioning key), yet retains the standard PostgreSQL interface.
In other words, TimescaleDB exposes what look like regular tables, but are actually only an abstraction (or a virtual view) of many individual tables comprising the actual data. This single-table view, which we call a hypertable, is comprised of many chunks, which are created by partitioning the hypertable's data in either one or two dimensions: by a time interval, and by an (optional) "partition key" such as device id, location, user id, etc. (Architecture discussion)
Virtually all user interactions with TimescaleDB are with hypertables. Creating tables and indexes, altering tables, inserting data, selecting data, etc., can (and should) all be executed on the hypertable.
From the perspective of both use and management, TimescaleDB just looks and feels like PostgreSQL, and can be managed and queried as such.
Before you start
PostgreSQL's out-of-the-box settings are typically too conservative for modern
servers and TimescaleDB. You should make sure your postgresql.conf
settings are tuned, either by using timescaledb-tune
or doing it manually.
Creating a hypertable
-- Do not forget to create timescaledb extension
CREATE EXTENSION timescaledb;
-- We start by creating a regular SQL table
CREATE TABLE conditions (
time TIMESTAMPTZ NOT NULL,
location TEXT NOT NULL,
temperature DOUBLE PRECISION NULL,
humidity DOUBLE PRECISION NULL
);
-- Then we convert it into a hypertable that is partitioned by time
SELECT create_hypertable('conditions', 'time');
Inserting and querying data
Inserting data into the hypertable is done via normal SQL commands:
INSERT INTO conditions(time, location, temperature, humidity)
VALUES (NOW(), 'office', 70.0, 50.0);
SELECT * FROM conditions ORDER BY time DESC LIMIT 100;
SELECT time_bucket('15 minutes', time) AS fifteen_min,
location, COUNT(*),
MAX(temperature) AS max_temp,
MAX(humidity) AS max_hum
FROM conditions
WHERE time > NOW() - interval '3 hours'
GROUP BY fifteen_min, location
ORDER BY fifteen_min DESC, max_temp DESC;
In addition, TimescaleDB includes additional functions for time-series
analysis that are not present in vanilla PostgreSQL. (For example, the time_bucket function above.)
Installation
TimescaleDB is available pre-packaged for several platforms:
Timescale Cloud (cloud-hosted and managed TimescaleDB) is available via free trial. You create database instances in the cloud of your choice and use TimescaleDB to power your queries, automating common operational tasks and reducing management overhead.
We recommend following our detailed installation instructions.
To build from source, see instructions here.
Resources
Useful tools
- timescaledb-tune: Helps set your PostgreSQL configuration settings based on your system's resources.
- timescaledb-parallel-copy:
Parallelize your initial bulk loading by using PostgreSQL's
COPYacross multiple workers.
Additional documentation
- Why use TimescaleDB?
- Migrating from PostgreSQL
- Writing data
- Querying and data analytics
- Tutorials and sample data
Community & help
- Slack Channel
- Github Issues
- Timescale Support: see support options (community & subscription)
Releases & updates
- Timescale Release Notes & Future Plans: see planned and in-progress updates and detailed information about current and past releases.
- Subscribe to Timescale Release Notes to get notified about new releases, fixes, and early access/beta programs.