Hi
>> +#define PG_STAT_STATEMENTS_COLS_V1_4 25
>
> I thought it was needed when adding new columns, isn't it ?
Yes, this is needed. I mean it should be PG_STAT_STATEMENTS_COLS_V1_8: because such change was made for 1.8
pg_stat_statementsversion. Same thing for other version-specific places.
regards, Sergei