? in explain query

Hi ,

In the explain below are the references
"outer"."?column2?" = "inner"."?column2?"

Ok?

rt3=# SELECT version();
version
----------------------------------------------------------------
PostgreSQL 7.4beta5 on i686-pc-linux-gnu, compiled by GCC 2.96
(1 row)

rt3=# explain analyze SELECT count(*) from Tickets main JOIN Groups as
Groups_1 ON ( main.id = Groups_1.Instance);
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------
Aggregate (cost=9047.54..9047.54 rows=1 width=0) (actual
time=2210.017..2210.018 rows=1 loops=1)
-> Merge Join (cost=7838.44..8914.51 rows=53211 width=0) (actual
time=1480.912..2111.089 rows=47152 loops=1)
Merge Cond: ("outer"."?column2?" = "inner"."?column2?")
-> Sort (cost=1057.51..1083.58 rows=10431 width=4) (actual
time=124.539..137.337 rows=10431 loops=1)
Sort Key: (main.id)::text
-> Seq Scan on tickets main (cost=0.00..361.31
rows=10431 width=4) (actual time=0.032..34.973 rows=10431 loops=1)
-> Sort (cost=6780.93..6936.18 rows=62097 width=8) (actual
time=1356.213..1483.773 rows=62097 loops=1)
Sort Key: (groups_1.instance)::text
-> Seq Scan on groups groups_1 (cost=0.00..1336.97
rows=62097 width=8) (actual time=0.017..170.204 rows=62097 loops=1)
Total runtime: 2216.263 ms
(10 rows)

rt3=#