To build these you will need the f5-threading library and a few Boost libraries. The .travis.yml file contains hints on how to get them and to do a build using Boost build.
For all of these examples (except the minimal one) the following options set Postgres connection details:
-h-- Full path to the Unix domain socket. Normally Postgres takes only the directory, but csj requires the full filename. The default is/var/run/postgresql/.s.PGSQL.5432.-U-- User name. Defaults to theLOGNAMEenvironment variable.-d-- Database name. Defaults to nothing, and the Postgres server defaults a missing database option to the user name.
A minimal example showing how use the basic APIs for connecting to the database and fetching data from the returned recordsets. To keep the example as simple as possible you will need to edit the source code if you need different connection settings.
Running it should give something like the following output:
Connected to /var/run/postgresql/.s.PGSQL.5432 as kirit
Data type for first column is 23 (23 means a 32 bit integer)
Data returned is: 42
This example produces some statistics (hence stats) about results from giving SQL to the database server. It also shows how to iterate over one or more statements that can produce multiple recordsets.
All of the coroutines used to service the connections run in the same thread (the main thread), so this example can be used to see how many connections a single thread can service for different statements given to the database server.
The option -c specifies a command that is to be run (and it may be provided multiple times). Otherwise pass in the filenames of SQL commands to be run.
Example:
stats -c "SELECT 1, 2" pgbench.sql
Run the SELECT statement in one coroutine and all of the SQL found in the pgbench.sql file in another.
stats pgbench.sql pgbench.sql pgbench.sql
Run three coroutines performing the SQL in the pgbench.sql file.
This shows how to use the basic parts of the libraries to efficiently fetch data from Postgres, do some light processing and then output the data. It demonstrates how the f5-threading library can be used to handle record data over multiple threads.
The CSJ format is described at Comma Separated JSON.
Example:
csj -h /run/postgresql/.s.PGSQL.5433 "SELECT * FROM pgbench_accounts"
Connects to the database server whose unix domain socket is at the file /run/postgresql/.s.PGSQL.5433 and displays all of the data in the pgbench_accounts table.