| pg_wait_sampling.history_size| int4| Size of history in-memory ring buffer| 5000|

| pg_wait_sampling.history_period| int4| Period for history sampling in milliseconds| 10|

| pg_wait_sampling.profile_period| int4| Period for profile sampling in milliseconds| 10|

| pg_wait_sampling.profile_pid| int4| Whether profile should be per pid| true|

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

If pg\_wait\_sampling.profile\_pid is set to false, sampling profile wouldn't be

collected in per-process manner. In this case the value of pid could would

be always zero and corresponding row contain samples among all the processes.

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.

probe_waits(History*observations,HTAB*profile_hash,

boolwrite_history,boolwrite_profile)

boolwrite_history,boolwrite_profile,boolprofile_pid)

{

inti,

newSize;

ProfileItem*profileItem;

boolfound;

if (!profile_pid)

item.pid=0;

profileItem= (ProfileItem*)hash_search(profile_hash,&item,HASH_ENTER,&found);

if (found)

profileItem->count++;

if (write_history||write_profile)

{

probe_waits(&observations,profile_hash,

write_history,write_profile);

write_history,write_profile,collector_hdr->profilePid);

if (write_history)

{

return true;

}

shmem_bool_guc_check_hook(bool*newval,void**extra,GucSourcesource)

{

if (UsedShmemSegAddr==NULL)

return false;

return true;

}

i;

boolhistory_size_found= false,

history_period_found= false,

profile_period_found= false;

profile_period_found= false,

profile_pid_found= false;

guc_vars=get_guc_variables();

numOpts=GetNumConfigOptions();

var->integer.variable=&collector_hdr->profilePeriod;

collector_hdr->profilePeriod=10;

}

elseif (!strcmp(name,"pg_wait_sampling.profile_pid"))

{

profile_pid_found= true;

var->_bool.variable=&collector_hdr->profilePid;

collector_hdr->profilePid= true;

}

}

if (!history_size_found)

&collector_hdr->profilePeriod,10,1,INT_MAX,

PGC_SUSET,0,shmem_int_guc_check_hook,NULL,NULL);

if (history_size_found||history_period_found||profile_period_found)

if (!profile_pid_found)

DefineCustomBoolVariable("pg_wait_sampling.profile_pid",

"Sets whether profile should be collected per pid.",NULL,

&collector_hdr->profilePid, true,

PGC_SUSET,0,shmem_bool_guc_check_hook,NULL,NULL);

if (history_size_found||history_period_found

||profile_period_found||profile_pid_found)

ProcessConfigFile(PGC_SIGHUP);

}

inthistorySize;

inthistoryPeriod;

intprofilePeriod;

boolprofilePid;

}CollectorShmqHeader;