Thread: PQfinish(const PGconn *conn) question

Hi,

I'm wondering how safe it is to pass an uninitialized conn to
PQfinish....

I have set a SIGALRM handler that terminates my daemon and closes
connection
to Postgres if time-out happens. However, Im setting the alarm few times
before the connection to Postgres was established... which means that
conn pointer in not initialized yet and it will be passed to PQfinish in
my
SIGALRM handler. Im not sure how Postgres will handle that.... so far
that
doesnt seem to be causing any errors but Im not sure what's actually
happening
behind the scenes...

Any input would be appreciated.



Regards,
Boulat Khakimov

--
Nothing Like the Sun

Greetings!  Why is the first query below so much longer than the
second?  The only difference is the replacement of dates.asof =
r1.asof with dates.asof = 'constant', even though
r1.asof='same-constant' is a condition earlier in the where clause.

Here are the details:

rdb1=# explain select r1.asof,r1.id,r1.price,r2.price,r1.dividend,r2.split,(r2.price*(case when r2.split isnull then
1.0else r2.split end)-r1.price+(case when r1.dividend isnull then 0.0 else r1.dividend end))/r1.price as ret,r2.mret
fromrprices r1,rprices r2,dates where r1.asof = '20010201' and r2.asof = dates.nasof and dates.asof = r1.asof and r1.id
=r2.id and r1.price != 0.0 order by r1.id; 
NOTICE:  QUERY PLAN:

Sort  (cost=29853.31..29853.31 rows=11 width=56)
  ->  Nested Loop  (cost=36.15..29853.12 rows=11 width=56)
        ->  Hash Join  (cost=36.15..1163.55 rows=260 width=28)
              ->  Index Scan using rprices_asof_key on rprices r1  (cost=0.00..1100.76 rows=298 width=20)
              ->  Hash  (cost=18.78..18.78 rows=1178 width=8)
                    ->  Seq Scan on dates  (cost=0.00..18.78 rows=1178 width=8)
        ->  Index Scan using rprices_id_key on rprices r2  (cost=0.00..109.76 rows=29 width=28)

EXPLAIN
rdb1=# explain select r1.asof,r1.id,r1.price,r2.price,r1.dividend,r2.split,(r2.price*(case when r2.split isnull then
1.0else r2.split end)-r1.price+(case when r1.dividend isnull then 0.0 else r1.dividend end))/r1.price as ret,r2.mret
fromrprices r1,rprices r2,dates where r1.asof = '20010201' and r2.asof = dates.nasof and dates.asof = '20010201' and
r1.id= r2.id and r1.price != 0.0 order by r1.id; 
NOTICE:  QUERY PLAN:

Sort  (cost=2235.40..2235.40 rows=13 width=52)
  ->  Hash Join  (cost=1101.51..2235.17 rows=13 width=52)
        ->  Nested Loop  (cost=0.00..1105.76 rows=605 width=32)
              ->  Index Scan using dates_pkey on dates  (cost=0.00..2.01 rows=1 width=4)
              ->  Index Scan using rprices_asof_key on rprices r2  (cost=0.00..1100.02 rows=298 width=28)
        ->  Hash  (cost=1100.76..1100.76 rows=298 width=20)
              ->  Index Scan using rprices_asof_key on rprices r1  (cost=0.00..1100.76 rows=298 width=20)

EXPLAIN
rdb1=# \d rprices
        Table "rprices"
 Attribute |  Type   | Modifier
-----------+---------+----------
 asof      | date    | not null
 id        | integer | not null
 rinfo     | integer | not null
 price     | float8  | not null
 ret       | float8  | not null
 dividend  | float4  |
 split     | float4  |
 volume    | integer |
 idcsplit  | float8  |
 idcdiv    | float8  |
 mret      | float8  |
Indices: rprices_asof_key,
         rprices_id_key

rdb1=# \d rprices_asof_key
Index "rprices_asof_key"
 Attribute |  Type
-----------+---------
 asof      | date
 id        | integer
unique btree

rdb1=# \d rprices_id_key
Index "rprices_id_key"
 Attribute |  Type
-----------+---------
 id        | integer
btree

rdb1=# \d dates
        Table "dates"
 Attribute | Type | Modifier
-----------+------+----------
 asof      | date | not null
 nasof     | date |
 pasof     | date |
Index: dates_pkey

rdb1=# \d dates_pkey
Index "dates_pkey"
 Attribute | Type
-----------+------
 asof      | date
unique btree (primary key)



Thanks!
--
Camm Maguire                             camm@enhanced.com
==========================================================================
"The earth is but one country, and mankind its citizens."  --  Baha'u'llah