[postgis-tickets] [PostGIS] #4857: Large ST_Union makes PostgreSQL temporarily unrestartable

[PostGIS]

#4857: Large ST_Union makes PostgreSQL temporarily unrestartable
-----------------------+---------------------------
  Reporter:  grassick  |      Owner:  pramsey
      Type:  defect    |     Status:  new
  Priority:  high      |  Milestone:  PostGIS 3.1.2
 Component:  postgis   |    Version:  3.1.x
Resolution:            |   Keywords:
-----------------------+---------------------------

Comment (by grassick):

 I double checked by using kill directly. With a SIGINT, it still takes at
 least 45 seconds to abort the query.

 The logs say:
 {{{
 2021-02-23 14:18:07.856 UTC [347211] LOG:  received fast shutdown request
 2021-02-23 14:18:07.859 UTC [347211] LOG:  aborting any active
 transactions
 2021-02-23 14:18:51.650 UTC [347272] postgres at mwater_opt FATAL:
 terminating connection due to administrator command
 2021-02-23 14:18:51.650 UTC [347272] postgres at mwater_opt STATEMENT:
 select ST_Union(ST_Buffer(location, 10000)) from test_union
 }}}

 If I interrupt it using pgAdmin, it stops instantly with:

 {{{
 2021-02-23 14:22:44.305 UTC [347394] postgres at mwater_opt ERROR:
 lwgeom_unaryunion_prec: GEOS Error: InterruptedException: Interrupted!
 2021-02-23 14:22:44.305 UTC [347394] postgres at mwater_opt STATEMENT:
 select ST_Union(ST_Buffer(location, 10000)) from test_union
 }}}

 The only conclusion seems to me to be that there are two types of aborts
 coming from PostgreSQL, one that PostGIS handles gracefully and the other
 that it doesn't. Unfortunately, I don't know enough about the inner
 workings to diagnose further.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/4857#comment:14>
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