pg_wait_sampling_reset_profile() function resets the profile.

The work of wait event statistics collector worker is controlled by following

GUCs.

| Parameter name| Data type| Description|

| -------------------------------| ---------| -------------------------------------------|

| pg_wait_sampling.history_size| int4| Size of history in-memory ring buffer|

| pg_wait_sampling.history_period| int4| Period for history sampling in milliseconds|

| pg_wait_sampling.profile_period| int4| Period for profile sampling in milliseconds|

These GUCs are allowed to be changed by superuser. Also, they are placed into

shared memory. Thus, they could be changed from any backend and affects worker

runtime.

See

[PostgreSQL documentation](http://www.postgresql.org/docs/devel/static/monitoring-stats.html#WAIT-EVENT-TABLE)

for list of possible wait events.