Re: BUG #13635: Interlocks at selection with array_agg

Hi, we generate sql query at php. And interval not overlaps by php code:

```

<?php
$connections = [];
for($i = 0; $i < 72; $i++){
$connections[] = pg_connect("***", PGSQL_CONNECT_FORCE_NEW);
pg_query("SET application_name = 'DB.Upgrade #{$i}'");
}

$chunk = 10000;

do{
foreach($connections as $id => $connection){
if(!pg_connection_busy($connection)) {
if($result = pg_get_result($connection)){
pg_free_result($result);
}
pg_send_query($connection, strtr('
UPDATE phone p
SET mailing_id = (
SELECT array_agg(mailing_id)
FROM message m
WHERE m.phone_id = p.phone_id
)
WHERE
p.phone_id BETWEEN :min AND :max
', [
':min' => $chunk,
':max' => $chunk+9999,
]));
$chunk += 10000;
}
}
usleep(100000);
}
while(true);

```

We assume that block throw when 2 phone at 2 different query has same
mailng_id. That possible only if selection create some locks.

2015-09-24 19:43 GMT+03:00 Francisco Olarte <folarte(at)peoplecall(dot)com>:

> Hi pawel:
>
> On Thu, Sep 24, 2015 at 11:56 AM, <pawel(dot)samysev(at)gmail(dot)com> wrote:
>
> Not seeing the whole query I cannot say too much but:
>
> > WHERE
> > p.phone_id BETWEEN :min AND :max
>
> ¿ Are you sure you're not getting fencepost overlaps when substituting
> :min/:max ? ( between does closed intervals, normally half closed (
> phone_id >= min and phone_id<max ) are used for this kinds of queries
> ( I ask because it seems a query doing b-c could lock out other doing
> a-b for a long time ).
>
> Francisco Olarte.
>

--

С уважением, Павел Самусев
+ 7 (926) 66 83 137
pawel(dot)samysev(at)gmail(dot)com