Boost leaking memory when a large number of Data Sources disabled

[TheWitness]

Describe the bug

During a Re-Index, if a Data Source is disabled, Cacti's API is not purging it's records from the Boost table resulting in memory leakage and failed boost runs.

To Reproduce

Steps to reproduce the behavior:

1. Create 10's of thousands of Data Sources from Data Queries

2. Have the re-index not fail, bur return only a fraction of the records.

3. Ensure your boost table has > 6M records

4. Attempt to do a boost run and watch the memory value. Boost can consume several GB of memory.

Expected behavior

Boost should not leak memory, Cacti should remove these Data Sources from the Boost tables as well during the disable process.

[ddb4github]

Just one comment:
function boost_rrdtool_function_update have only two return_value '' or OK

• In most case, function boost_rrdtool_function_update return OK
• If rrdfile not exist, and create fail, function boost_rrdtool_function_update return ''
• boost_process_output output WARN message if return_value is ''
• boost_process_poller_output always ignore return_value whatever '' and OK

So I prefer to ignore '' in boost_process_output, and do not output WARN for each disabled DataSource:

2020/04/21 05:17:45 - BOOST WARNING: RRD Update Warning '' for Local Data ID '97063'

[TheWitness]

I agree.