Re: cursor use vs pg_stat_statements

On 10/20/21 9:02 AM, Laurenz Albe wrote:
> On Tue, 2021-10-19 at 15:24 -0400, Andrew Dunstan wrote:
>> The problem I'm writing about (h/t Simon Riggs for finding it) is
>> illustrated by the following snippet of java:
>>
>>       public static void runtest(Connection conn) throws Exception {
>>         Statement stmt = conn.createStatement();
>>         stmt.setFetchSize(10);
>>         ResultSet rs = stmt.executeQuery("select oid, relfileid, relname from pg_class");
>>         int count = 100;
>>         while (rs.next() && count-- > 0) {
>>           System.out.print(".");
>>         }
>>         rs.close();
>>         stmt.commit();
>>         stmt.close();
>>         System.out.println("");
>>       }
>>
>> When called, this prints out a line with 100 dots showing 100 lines were
>> fetched, but pg_stat_statements shows this:
>>
>>     query | select oid, relfilenode, relname from pg_class
>>     calls | 1
>>     rows  | 10
>>
>>
>> suggesting only 10 rows were returned. It appears that only the first
>> "EXECUTE 10" command against the portal is counted. At the very least
>> this is a POLA violation, and it seems to be a bug. Maybe it's
>> documented somewhere but if so it's not obvious to me.
> I can't reproduce this on 14.1, after fixing the errors in your code:
>
>

Try again with autocommit turned off. Sorry, I omitted that crucial
detail. Exact test code attached (name/password removed)


cheers


andrew


--
Andrew Dunstan
EDB: https://www.enterprisedb.com