Re: [PROPOSAL] VACUUM Progress Checker.

Hi Vinayak,

Thanks for updating the patch! A quick comment:

On 2016/02/26 17:28, pokurev@pm.nttdata.co.jp wrote:
>> CREATE VIEW pg_stat_vacuum_progress AS 
>>   SELECT S.s[1] as pid, 
>>          S.s[2] as relid, 
>>          CASE S.s[3] 
>>            WHEN 1 THEN 'Scanning Heap' 
>>            WHEN 2 THEN 'Vacuuming Index and Heap' 
>>            ELSE 'Unknown phase' 
>>          END, 
>>    .... 
>>   FROM pg_stat_get_command_progress(PROGRESS_COMMAND_VACUUM) as S; 
>>
>> # The name of the function could be other than *_command_progress.
> The name of function is updated as pg_stat_get_progress_info() and also updated the function.
> Updated the pg_stat_vacuum_progress view as suggested.

So, pg_stat_get_progress_info() now accepts a parameter to distinguish
different commands.  I see the following in its definition:

+        /*  Report values for only those backends which are running VACUUM
command */
+        if (cmdtype == COMMAND_LAZY_VACUUM)
+        {
+            /*Progress can only be viewed by role member.*/
+            if (has_privs_of_role(GetUserId(), beentry->st_userid))
+            {
+                values[2] = UInt32GetDatum(beentry->st_progress_param[0]);
+                values[3] = UInt32GetDatum(beentry->st_progress_param[1]);
+                values[4] = UInt32GetDatum(beentry->st_progress_param[2]);
+                values[5] = UInt32GetDatum(beentry->st_progress_param[3]);
+                values[6] = UInt32GetDatum(beentry->st_progress_param[4]);
+                values[7] = UInt32GetDatum(beentry->st_progress_param[5]);
+                if (beentry->st_progress_param[1] != 0)
+                    values[8] = Float8GetDatum(beentry->st_progress_param[2] * 100 /
beentry->st_progress_param[1]);
+                else
+                    nulls[8] = true;
+            }
+            else
+            {
+                nulls[2] = true;
+                nulls[3] = true;
+                nulls[4] = true;
+                nulls[5] = true;
+                nulls[6] = true;
+                nulls[7] = true;
+                nulls[8] = true;
+            }
+        }

How about doing this in a separate function which takes the command id as
parameter and returns an array of values and the number of values (per
command id). pg_stat_get_progress_info() then creates values[] and nulls[]
arrays from that and returns that as result set.  It will be a cleaner
separation of activities, perhaps.

Thanks,
Amit