Thread: BUG #15998: query to return a table column list gives error on a missing foreign data wrapper library
BUG #15998: query to return a table column list gives error on a missing foreign data wrapper library
From
PG Bug reporting form
Date:
The following bug has been logged on the website:
Bug reference: 15998
Logged by: reiner peterke
Email address: zedaardv@drizzle.com
PostgreSQL version: 11.5
Operating system: Centos 7.6.1810 x86
Description:
This is a very corner case situation.
Found originally with the oracle_fdw but can reproduce with the
postgres_fdw.
Happened on at a customers site when we changed the binaries from postgres
from community version to another version.
database server was started without the foreign data wrapper having been
installed (tested with oracle_fdw and postgres_fdw)
a query was run from a GUI tool to get the column list for a non-foreign
table. when the query was run the error was thrown
ERROR: could not access file "$libdir/oracle_fdw": No such file or
directory
Have been able to reproduce the behavior on postgres 10 and 11 with the
postgres_fdw on centos 7 on ppc64le.
Take a postgres database with foreign servers and foreign tables.
remove the fdw library.
i simulated this by
mv postgres_fdw.so postgres_fdw.so.xx
run the query below on a normal table
the query needs to be adjusted to to have a table oid (version runs in
postgres 11)
SELECT
typ.oid AS typoid, nspname, relname, attname, attrelid, attnum,
attnotnull,
attidentity != '' AS isidentity,
CASE WHEN typ.typtype = 'd' THEN typ.typtypmod ELSE atttypmod
END AS typmod,
CASE WHEN atthasdef THEN (SELECT pg_get_expr(adbin, cls.oid)
FROM pg_attrdef WHERE adrelid = cls.oid AND adnum = attr.attnum) ELSE NULL
END AS default,
CASE WHEN col.is_updatable = 'YES' THEN true ELSE false END AS
is_updatable,
EXISTS (
SELECT * FROM pg_index
WHERE pg_index.indrelid = cls.oid AND
pg_index.indisprimary AND
attnum = ANY (indkey)
) AS isprimarykey,
EXISTS (
SELECT * FROM pg_index
WHERE pg_index.indrelid = cls.oid AND
pg_index.indisunique AND
pg_index.indnkeyatts = 1 AND
attnum = pg_index.indkey[0]
) AS isunique
FROM pg_attribute AS attr
JOIN pg_type AS typ ON attr.atttypid = typ.oid
JOIN pg_class AS cls ON cls.oid = attr.attrelid
JOIN pg_namespace AS ns ON ns.oid = cls.relnamespace
LEFT OUTER JOIN information_schema.columns AS col ON
col.table_schema = nspname AND
col.table_name = relname AND
col.column_name = attname
WHERE
atttypid <> 0 AND
relkind IN ('r', 'v', 'm') AND
NOT attisdropped AND
nspname NOT IN ('pg_catalog', 'information_schema') AND
attnum > 0 AND
((attr.attrelid=1354075 AND attr.attnum=1))
ORDER BY attnum
throws error
ERROR: could not access file "$libdir/postgres_fdw": No such file or
directory
commenting out the case statement
CASE WHEN col.is_updatable = 'YES' THEN true ELSE false END AS
is_updatable,
causes the query to run without error.
It seems odd to me that this query generates such an error
running a query with just the case statement works fine.
select case when col.is_updatable = 'YES' then true else false end as
is_updatable from information_schema.columns col where table_name =
'batch';
I am not sure how to dig further into this at the moment
Re: BUG #15998: query to return a table column list gives error on amissing foreign data wrapper library
From
Etsuro Fujita
Date:
On Tue, Sep 10, 2019 at 6:46 PM PG Bug reporting form
<noreply@postgresql.org> wrote:
> Have been able to reproduce the behavior on postgres 10 and 11 with the
> postgres_fdw on centos 7 on ppc64le.
> Take a postgres database with foreign servers and foreign tables.
> remove the fdw library.
> i simulated this by
> mv postgres_fdw.so postgres_fdw.so.xx
>
> run the query below on a normal table
> the query needs to be adjusted to to have a table oid (version runs in
> postgres 11)
> SELECT
> typ.oid AS typoid, nspname, relname, attname, attrelid, attnum,
> attnotnull,
> attidentity != '' AS isidentity,
> CASE WHEN typ.typtype = 'd' THEN typ.typtypmod ELSE atttypmod
> END AS typmod,
> CASE WHEN atthasdef THEN (SELECT pg_get_expr(adbin, cls.oid)
> FROM pg_attrdef WHERE adrelid = cls.oid AND adnum = attr.attnum) ELSE NULL
> END AS default,
> CASE WHEN col.is_updatable = 'YES' THEN true ELSE false END AS
> is_updatable,
> EXISTS (
> SELECT * FROM pg_index
> WHERE pg_index.indrelid = cls.oid AND
> pg_index.indisprimary AND
> attnum = ANY (indkey)
> ) AS isprimarykey,
> EXISTS (
> SELECT * FROM pg_index
> WHERE pg_index.indrelid = cls.oid AND
> pg_index.indisunique AND
> pg_index.indnkeyatts = 1 AND
> attnum = pg_index.indkey[0]
> ) AS isunique
> FROM pg_attribute AS attr
> JOIN pg_type AS typ ON attr.atttypid = typ.oid
> JOIN pg_class AS cls ON cls.oid = attr.attrelid
> JOIN pg_namespace AS ns ON ns.oid = cls.relnamespace
> LEFT OUTER JOIN information_schema.columns AS col ON
> col.table_schema = nspname AND
> col.table_name = relname AND
> col.column_name = attname
> WHERE
> atttypid <> 0 AND
> relkind IN ('r', 'v', 'm') AND
> NOT attisdropped AND
> nspname NOT IN ('pg_catalog', 'information_schema') AND
> attnum > 0 AND
> ((attr.attrelid=1354075 AND attr.attnum=1))
> ORDER BY attnum
>
> throws error
> ERROR: could not access file "$libdir/postgres_fdw": No such file or
> directory
I'm now traveling, so I cannot try to reproduce this. Could you send
the EXPLAIN output for this query?
> commenting out the case statement
> CASE WHEN col.is_updatable = 'YES' THEN true ELSE false END AS
> is_updatable,
>
> causes the query to run without error.
Seems reasonable to me; the is_updatable reference would cause the
IsForeignRelUpdatable() call for postgres_fdw foreign tables IIUC, so
removing that would be a workaround for this issue if that works for
you.
Best regards,
Etsuro Fujita
Re: BUG #15998: query to return a table column list gives error on a missing foreign data wrapper library
From
Tom Lane
Date:
Etsuro Fujita <etsuro.fujita@gmail.com> writes:
> On Tue, Sep 10, 2019 at 6:46 PM PG Bug reporting form
> <noreply@postgresql.org> wrote:
>> Take a postgres database with foreign servers and foreign tables.
>> remove the fdw library.
>> [ Then a query on information_schema.columns ]
>> throws error
>> ERROR: could not access file "$libdir/postgres_fdw": No such file or
>> directory
>>
>> commenting out the case statement
>> CASE WHEN col.is_updatable = 'YES' THEN true ELSE false END AS
>> is_updatable,
>> causes the query to run without error.
> Seems reasonable to me; the is_updatable reference would cause the
> IsForeignRelUpdatable() call for postgres_fdw foreign tables IIUC, so
> removing that would be a workaround for this issue if that works for
> you.
Yeah. Seems like not-a-bug to me: if you inquire about the updatability
of a foreign table, we really can't answer that without consulting
the relevant FDW.
regards, tom lane