= This is ipp's wiki of 3pi pv2 ob in psps =

First step is to do some sanity check queries to determine what is good / bad, second is to flag things to fix for PV3.

== Detection Counts ==

Total counts:

 * select count_big(*) from !ObjectThin

  * 4,460,992,385

I then did counts to find out how many have x detections or x stackdetections (up to 20 in both). For easy comparisons, I show both tables side by side (they are not related):
|| stacks || stacks || || single exp || single exp || ||
||nstackdetections || count || || ndetections || count ||comment ||
||0 ||3,271,281,682 || || 0 || 462,983,177 || 3.2 billion things have no stack detections. .46 billion have 0 detections (aka, stack only) ||
||1 || 420,775,092  || || 1 || 3,158,911,897 ||  3.1 billion things have only 1 detection, and .42 billion have only 1 stack ||
||2 ||156,692,049  || ||2||254,952,659||  n detections decreases (not surprising)||
||3 ||110,625,647  || || 3||52,419,438 ||  ||
||4 ||139,184,223  || || 4||30,750,181||  ||
||5 ||254,028,340  || || 5||21,236,521||  not surprising, a peak at 5 nstack detections (1 per filter) , and a peak at 10, and a peak at 15, and t 20...||
||6 ||19,227,731  || || 6||17,913,219||  ||
||7||3,859,474  || || 7||15,038,140||  ||
||8||23,245,260  || || 8||13,648,608||  ||
||9||3,314,548  || || 9||12,232,408||  ||
||10||52,135,360  || || 10||11,502,291||  ||
||11||343,750  || || 11||10,612,853||  ||
||12||1,179,799  || || 12||10,129,705||  ||
||13||165,876  || || 13||9,571,724||  ||
||14||158,566  || || 14||9,257,316||  ||
||15||1,310,614  || || 15||8,869,369||  ||
||16||886,362  || || 16||8,656,862||  ||
||17||85,019  || || 17||8,368,348||  ||
||18||82,064  || || 18||8,235,649||  ||
||19||102,699  || || 19||8,019,806||  ||
||20||2,259,605  || || 20||7,964,360||  ||

== 2d detection/stackdetection counts ==

 * Another sanity check, do we have any with ndetections = 0 and nstackdetections = 0 ?
  * yes we do: this happened on a full batch, 12884 - all detections were basically null, except for the ramean/decmean.  This was at ra = 0 dec = -33.
  * Is it PSPS or IPPTOPSPS's fault? I downloaded 12884's batch and investigated, it looks like we shipped them 0's.
  * Is it IPPTOPSPS or DVO's fault?  Where are the 0's? This is stage_id 121470, which translates to region s3000/6992.13.  This is located here:  /data/stsci00.0/eugene/lap.pv2.20141215/catdir.01/s3000/6992.13* . I opened the files in topcat, and there are 0's, so ipptopsps did the correct thing, but the dvo was incorrect.

Here is a plot of counts of nstackdetection vs ndetection:

[[Image(2dplotndetstackdet.png)]]

You can see the hole at 0,0 -- that should be 0 but instead is something like a million or less entries have that. 

* can I categorize this better, can I find where there are more of these funky batches?
  * yes : can I do a query of select batchid, count_big(*) from ObjectThin where nstackdetections = 0 and ndetections = 0 group by batchid --> into query called 'funkybatches'