Re: array_agg cast issue

pinker <pinker(at)onet(dot)eu> writes:
> I took a query from wiki
> <https://wiki.postgresql.org/wiki/Index_Maintenance#Duplicate_indexes> :

> SELECT pg_size_pretty(SUM(pg_relation_size(idx))::BIGINT) AS SIZE,
> (array_agg(idx))[1] AS idx1, (array_agg(idx))[2] AS idx2,
> (array_agg(idx))[3] AS idx3, (array_agg(idx))[4] AS idx4
> FROM (
> SELECT indexrelid::regclass AS idx, (indrelid::text ||E'\n'||
> indclass::text ||E'\n'|| indkey::text ||E'\n'||
> COALESCE(indexprs::text,'')||E'\n'
> || COALESCE(indpred::text,'')) AS KEY
> FROM pg_index) sub
> GROUP BY KEY HAVING COUNT(*)>1
> ORDER BY SUM(pg_relation_size(idx)) DESC;

> *and the result:*
> ERROR: function array_agg(regclass) is not unique
> LINE 2: (array_agg(idx))[1] AS idx1, (array_agg(idx))[2] AS i...
> ^
> HINT: Could not choose a best candidate function. You might need to add
> explicit type casts.

That example works fine for me. Maybe you have an extra user-defined
function named "array_agg"? Doing "\df array_agg" in psql might be
informative.

regards, tom lane