Thread: BUG #4232: CREATE INDEX CONCURRENTLY

The following bug has been logged online:

Bug reference:      4232
Logged by:          Lawrence Cohan
Email address:      lawrencec@1shoppingcart.com
PostgreSQL version: 8.2.5
Operating system:   Redhat Linux 4.1.1
Description:        CREATE INDEX CONCURRENTLY
Details:

We must run maintenance tasks like analyze, reindex and vacuum against our
PG databases however due to the fact that we are running a 24/7 system that
requires database access the reindex at the database level is way too heavy
and it is generating deadlocks. I created a job to CREATE INDEX CONCURRENTLY
on all user tables and DROP existing INDEX so we don’t impact our
production and now our application is getting errors (like the one below)
just because the OID for the index was changed. Is there anything we could
do to workaround this issue as so far the only option that clears it is an
IIS RESET.

Exception Type: Npgsql.NpgsqlException
Item: NULL
Severity: ERROR
Code: XX000
BaseMessage: could not open relation with OID 517613
Detail:
Hint:
Position:
Where: SQL statement "SELECT id FROM coupons WHERE merchant_id =  $1  AND
code =  $2 "
PL/pgSQL function "set_coupon" line 7 at SQL statement
File: heapam.c
Line: 700
Routine: relation_open
ErrorSql: select * from
set_coupon(NULL::int4,91221::int4,'11111'::text,'11111'::text,'1'::int4,NULL
::int4,0::int4,'1'::int4,11::numeric,0::numeric,'2008-06-10'::date,NULL::dat
e,TRUE::bool,FALSE::bool)
Errors: System.Collections.ArrayList
Message: ERROR: XX000: could not open relation with OID 517613
Data: System.Collections.ListDictionaryInternal
TargetSite: Void CheckErrors()
HelpLink: NULL
Source: Npgsql


Thanks,
Lawrence Cohan.

"Lawrence Cohan" <lawrencec@1shoppingcart.com> writes:
> We must run maintenance tasks like analyze, reindex and vacuum against our
> PG databases however due to the fact that we are running a 24/7 system that
> requires database access the reindex at the database level is way too heavy
> and it is generating deadlocks. I created a job to CREATE INDEX CONCURRENTLY
> on all user tables and DROP existing INDEX so we don’t impact our
> production and now our application is getting errors (like the one below)
> just because the OID for the index was changed. Is there anything we could
> do to workaround this issue as so far the only option that clears it is an
> IIS RESET.

Presumably the errors are coming from re-use of cached plans.  The only
really simple solution would be to upgrade to PG 8.3, which knows about
regenerating cached plans when needed.

            regards, tom lane

Many thanks - we actually considered that at some point and I looked for
more specific info on this particular issue and I found about the new
pg_stat_clear_snapshot() function in 8.3 as well.=20
Now that we know that this issue was fixed in 8.3 already it's even more
incentive for us to plan for an upgrade.

Lawrence Cohan.

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]=20
Sent: Tuesday, June 10, 2008 4:58 PM
To: Lawrence Cohan
Cc: pgsql-bugs@postgresql.org
Subject: Re: [BUGS] BUG #4232: CREATE INDEX CONCURRENTLY=20

"Lawrence Cohan" <lawrencec@1shoppingcart.com> writes:
> We must run maintenance tasks like analyze, reindex and vacuum against
our
> PG databases however due to the fact that we are running a 24/7 system
that
> requires database access the reindex at the database level is way too
heavy
> and it is generating deadlocks. I created a job to CREATE INDEX
CONCURRENTLY
> on all user tables and DROP existing INDEX so we don't impact our
> production and now our application is getting errors (like the one
below)
> just because the OID for the index was changed. Is there anything we
could
> do to workaround this issue as so far the only option that clears it
is an
> IIS RESET.

Presumably the errors are coming from re-use of cached plans.  The only
really simple solution would be to upgrade to PG 8.3, which knows about
regenerating cached plans when needed.

            regards, tom lane
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