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Postgres SQL Interface (pgwire)

pgwire is a proxy process which implements the Postgres wire protocol (binary and text) v3 server. Each Postgres client connection corresponds to a single TCP connection to the kdb Insights Core host which should be running s.k_.

pgwire is available for Windows, Linux, or MacOS. It may be deployed on:

  • The client machine alongside the Postgres client (for example: on your Windows desktop that is running the PowerBI or HeidiSQL client).

  • The server machine alongside kdb Insights Core (for example: both the q and pgwire processes are on your Linux server with the DbVisualizer client on your MacOS machine).

Supported clients

You can use SQL clients like Tableau, HeidiSQL, PowerBI, DBVisualizer or Grafana. The query builders within these clients make it very easy for an end user to visualise the tables and automatically build the ANSI SQL statements.

The following versions of those clients are supported.

client version
Tableau 2021.4.1
HeidiSQL 11.3.0.6295
PowerBI 2.95 (July 2021)
DBVisualizer 13.0.2
Grafana 9.0.0

Note

As new versions of these popular clients are released we endeavour to add support for those newer versions over time.

Running pgwire

The parameters for running pgwire are as follows:

pg [-T kdb_timeout][-I interface][-v] listen_port kdb_host kdb_port
properties description example
listen_port local port 5434
kdb_host IP Address of the kdb+ database 10.0.2.2
kdb_port Port of the kdb+ database 5001
-T Connection timeout (seconds) 0 (default: 0)
-I Listening interface 127.0.0.1 (default: 0.0.0.0)
-v verbose logging level, printed to stdout and stderr

SQL Integration using pgwire

This section describes how to install pgwire and use it to connect Tableau and Power BI to a kdb Insights Core database.

Create a PostgreSQL proxy server

This section details how to use pgwire to create a PostgreSQL proxy server which will enable Tableau and Power BI to connect to a kdb Insights Core database.

  1. Launch q

    1. Set the q process on a port

      q -p 5001
      
    2. Load s.k_

      \l s.k_
      
    3. Load the database of your choice

      \l databasefile
      
  2. Run pgwire and create a proxy PostgreSQL server

    1. Extract kxsql zip file

    2. Start pgwire

      • Open a command prompt and navigate to the subfolder 'w64' of the extracted zip file

      • Run the following command:

      pg listen_port kdb_host kdb_port
      
      • Navigate to the extracted zip file.

      • Run the following command:

      ./pgmac listen_port kdb_host kdb_port 
      

      Note

      There needs to be a kdb Insights Core server running on kdb_host:kdb_port with s.k_ loaded.

      Running the command with the example properties would result in pgwire providing a proxy PostgreSQL server running on port 5434 of the 'localhost' that accesses the kdb Insights Core database available at 10.0.2.2:5001.

Integration with Tableau

This section details how connect Tableau to the PostgreSQL proxy server, created above, allowing Tableau to connect to a kdb+ database.

  1. Download and install the PostgreSQL Driver, as described here

  2. Connect the new PostgreSQL proxy server to Tableau.

    1. Launch the Tableau Desktop
    2. Under Connect, select the PostgreSQL database option
    3. Enter the following properties:

      properties description example
      Server IP address of the proxy PostgreSQL server 127.0.0.1
      Port Port of the proxy PostgreSQL server 5433
      Database Database to connect to databasefile
      Authentication: Username The username on the kdb Insights Core server username
      Authentication: Password If this is not required, you still need to enter at least one character password
      Require SSL SSL Encryption Option untick
    4. Select Sign In.

    See PostgreSQL Connector for Tableau for additional details on creating the connection.

Integration with Power BI

This section details how connect Power BI to the PostgreSQL proxy server, created above, allowing Power BI to connect to a kdb+ database.

  1. Launch Power BI.

  2. Select 'PostgreSQL database' in the Connector selection.

  3. Enter the following:

    properties description example
    Server listen_port (as specified in the previous step) 127.0.0.1:5433
    Database field must not be empty, but is ignored by kdb+ proxy PostgreSQL server db
    Data Connectivity mode with Import it does a single retrieval of data and executes all other queries locally. With Direct SQL it goes to kdb Insights Core for each query. Import or DirectQuery, both are supported

    See PostgreSQL Connector for Power BI for additional details on creating the connection.

  4. Click OK

  5. On the Database screen enter your kdb Insights Core credentials:

    properties example
    User name kdb Insights Core User Name
    Password kdb Insights Core Password
    level Leave as default

    See here for how to set the username and password for kdb Insights Core.

Each postgres client connection corresponds to a single tcp connection to a kdb Insights Core host running s.k.

Logging failed queries

A table can be created that includes all all failed SQL queries.

.z.pg:{$[$[0=type x;".s.spg"~x 0;0b];$[10h=type r:@[value;.sql.last:0N!x;::];[.sql.err,:enlist`query`error!(x;r);r];r];value x]}

It can also be enhanced to log all queries if an audit trail is required.