Re: POC: Extension for adding distributed tracing - pg_tracing

Please check some suggested improvements -

1) query_id added so span to be able to join it with pg_stat_activity and pg_stat_statements;

2) table for storing spans added, to flush spans buffer, for maintenance reasons - to keep track of spans,

with SQL function that flushes buffer into table instead of recordset;

3) added setter function for sampling_rate GUC to tweak it on-the-fly without restart.