Mysterious query plan

Hi -

I mistyped a table name in the following query:

   select * from gazContainers
    where gazPlaceID in (select gazPlaceID from tipsterAuxiliary);

Turns out there's no gazPlaceID column in tipsterAuxiliary, so the
inner gazPlaceID was referring to the outer gazContainers table.  This
ran all night without finishing, before I discovered my mistake.  What
I can't figure out is just what the query planner came up with.  Can
someone explain it to me?  Is it effectively some sort of horrible
cross join?  Here's the terse query plan:

   Seq Scan on gazcontainers  (cost=0.00..10830971486.25 rows=2935950
width=8)
     Filter: (subplan)
     SubPlan
       ->  Seq Scan on tipsterauxiliary  (cost=0.00..3330.04 rows=143604
width=0)

and appended below is the verbose output.  Any explanation is very much
appreciated.  Thanks!

- John D. Burger
   MITRE

                                    QUERY PLAN
------------------------------------------------------------------------
--------
     {SEQSCAN
     :startup_cost 0.00
     :total_cost 10830971486.25
     :plan_rows 2935950
     :plan_width 8
     :targetlist (
        {TARGETENTRY
        :resdom
           {RESDOM
           :resno 1
           :restype 23
           :restypmod -1
           :resname gazplaceid
           :ressortgroupref 0
           :resorigtbl 288092363
           :resorigcol 1
           :resjunk false
           }

        :expr
           {VAR
           :varno 1
           :varattno 1
           :vartype 23
           :vartypmod -1
           :varlevelsup 0
           :varnoold 1
           :varoattno 1
           }
        }

        {TARGETENTRY
        :resdom
           {RESDOM
           :resno 2
           :restype 23
           :restypmod -1
           :resname containerid
           :ressortgroupref 0
           :resorigtbl 288092363
           :resorigcol 2
           :resjunk false
           }

        :expr
           {VAR
           :varno 1
           :varattno 2
           :vartype 23
           :vartypmod -1
           :varlevelsup 0
           :varnoold 1
           :varoattno 2
           }
        }
     )

     :qual (
        {SUBPLAN
        :subLinkType 2
        :useOr false
        :exprs (
           {OPEXPR
           :opno 96
           :opfuncid 65
           :opresulttype 16
           :opretset false
           :args (
              {VAR
              :varno 1
              :varattno 1
              :vartype 23
              :vartypmod -1
              :varlevelsup 0
              :varnoold 1
              :varoattno 1
              }

              {PARAM
              :paramkind 15
              :paramid 1
              :paramname <>
              :paramtype 23
              }
           )
           }
        )

        :paramIds ( 1)

        :plan
           {SEQSCAN
           :startup_cost 0.00
           :total_cost 3330.04
           :plan_rows 143604
           :plan_width 0
           :targetlist (
              {TARGETENTRY
              :resdom
                 {RESDOM
                 :resno 1
                 :restype 23
                 :restypmod -1
                 :resname gazplaceid
                 :ressortgroupref 0
                 :resorigtbl 288092363
                 :resorigcol 1
                 :resjunk false
                 }

              :expr
                 {PARAM
                 :paramkind 15
                 :paramid 0
                 :paramname <>
                 :paramtype 23
                 }
              }
           )

           :qual <>
           :lefttree <>
           :righttree <>
           :initPlan <>
           :extParam ( 0)

           :allParam ( 0)

           :nParamExec 0
           :scanrelid 1
           }

        :plan_id 4
        :rtable (
           {RTE
           :alias <>
           :eref
              {ALIAS
              :aliasname tipsterauxiliary
              :colnames ("sourceid" "name" "type" "containername1"
"containertyp
              e1" "containername2" "containertype2" "containername3"
"containert
              ype3" "modifier" "linenum")
              }

           :rtekind 0
           :relid 298199547
           :inh false
           :inFromCl true
           :checkForRead true
           :checkForWrite false
           :checkAsUser 0
           }
        )

        :useHashTable false
        :unknownEqFalse true
        :setParam ()

        :parParam ( 0)

        :args (
           {VAR
           :varno 1
           :varattno 1
           :vartype 23
           :vartypmod -1
           :varlevelsup 0
           :varnoold 1
           :varoattno 1
           }
        )
        }
     )

     :lefttree <>
     :righttree <>
     :initPlan <>
     :extParam ()

     :allParam ( 1)

     :nParamExec 2
     :scanrelid 1
     }