CREATE RANDOM STREAM

You may use this special stream to generate random data for tests. For example:

CREATE RANDOM STREAM devices(
  device string default 'device'||to_string(rand()%4),
  location string default 'city'||to_string(rand()%10),
  temperature float default rand()%1000/10);

The following functions are available to use:

rand to generate a number in uint32
rand64 to generate a number in uint64
random_printable_ascii to generate printable characters
random_string to generate a string
random_fixed_string to generate string in fixed length
random_in_type to generate value with max value and custom logic

The data of random stream is kept in memory during the query time. If you are not querying the random stream, there is no data generated or kept in memory.

By default, Timeplus tries to generate as many data as possible. If you want to (roughly) control how frequent the data is generated, you can use the eps setting. For example, the following SQL generates 10 events every second:

CREATE RANDOM STREAM rand_stream(i int default rand()%5) SETTINGS eps=10

You can further customize the rate of data generation via the interval_time setting. For example, you want to generate 1000 events each second, but don't want all 1000 events are generated at once, you can use the following sample SQL to generate events every 200 ms. The default interval is 5ms (in Proton 1.3.27 or the earlier versions, the default value is 100ms)

CREATE RANDOM STREAM rand_stream(i int default rand()%5) SETTINGS eps=1000, interval_time=200

Please note, the data generation rate is not accurate, to balance the performance and flow control.

info

New in Proton v1.4.2, you can set eps less than 1. Such as eps=0.5 will generate 1 event every 2 seconds. eps less than 0.00001 will be treated as 0.

For testing or demonstration purpose, you can create a random stream with multiple columns and use the table function to generate random data at once. The number of rows generated by this way is predefined and subject to change. The current value is 65409.