• indicator
  • kpi
  • measure
  • performance
  • strategic

Query the Data Delivery Network

Query the DDN

The easiest way to query any data on Splitgraph is via the "Data Delivery Network" (DDN). The DDN is a single endpoint that speaks the PostgreSQL wire procotol. Any Splitgraph user can connect to it at data.splitgraph.com:5432 and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.

For example, you can query the strategic_performance_measures table in this repository, by referencing it like:


or in a full query, like:

    ":id", -- Socrata column ID
    "datasource", -- A description of the source used to derive the performance number.
    "measureunit", -- The unit of measure
    "metricvalue", -- The number representing performance for a given reporting period.
    "metricdate", -- The date representing the end of the reporting period. (For example, the date for a number representing the year 2016 would be December 31,2016.)
    "status", -- Whether the performrance measure is in active use. (Only actively used measures are published.)
    "segment", -- This is generally used to indicate the political unit (e.g. county) to which the measure applies.  It is typically used to indicate a county against which Fulton County is benchmarked.
    "mostrecent", -- This has a value of Yes when the record contains the most recent available for the measure.
    "id", -- Unique identifer for each performance measure.
    "priorityarea", -- One of six strategic priority areas to which each performance measure is aligned.
    "metricdescription", -- A description of the strategic performance measure.
    "measurecalcmethod", -- The calculation used to derive the performance number if a calculation is used.
    "metricnotes", -- Any clarifying notes regarding the performance measure.
    "category", -- This is used when a measure is subdivided by category. (For example, the college education rate is subdivided by degree level.)
    "measuretype", -- The type of measure (number, percentage, or currency).
    "marginoferror", -- The margin of error when reported by the data source.
    "metricname" -- The name of the strategic performance measure.
LIMIT 100;

Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query fultoncountyga-gov/strategic-performance-measures-izxk-dx9e with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.fultoncountyga.gov. When you queryfultoncountyga-gov/strategic-performance-measures-izxk-dx9e:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).

We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.

Query Your Local Engine

Install Splitgraph Locally

bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"

Splitgraph Cloud is built around Splitgraph Core (GitHub), which includes a local Splitgraph Engine packaged as a Docker image. Splitgraph Cloud is basically a scaled-up version of that local Engine. When you query the Data Delivery Network or the REST API, we mount the relevant datasets in an Engine on our servers and execute your query on it.

It's possible to run this engine locally. You'll need a Mac, Windows or Linux system to install sgr, and a Docker installation to run the engine. You don't need to know how to actually use Docker; sgrcan manage the image, container and volume for you.

There are a few ways to ingest data into the local engine.

For external repositories (like this repository), the Splitgraph Engine can "mount" upstream data sources by using sgr mount. This feature is built around Postgres Foreign Data Wrappers (FDW). You can write custom "mount handlers" for any upstream data source. For an example, we blogged about making a custom mount handler for HackerNews stories.

For hosted datasets, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.

Mounting Data

This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.fultoncountyga.gov, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone to get the data. Instead, you can use the socrata adapter with the sgr mount command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.

First, install Splitgraph if you haven't already.

Mount the table with sgr mount

sgr mount socrata \
  "fultoncountyga-gov/strategic-performance-measures-izxk-dx9e" \
  --handler-options '{
    "domain": "data.fultoncountyga.gov",
    "tables": {
        "strategic_performance_measures": "izxk-dx9e"

That's it! Now you can query the data in the mounted table like any other Postgres table.

Query the data with your existing tools

Once you've loaded the data into your local Splitgraph engine, you can query it with any of your existing tools. As far as they're concerned, fultoncountyga-gov/strategic-performance-measures-izxk-dx9e is just another Postgres schema.

Related Documentation: