Hi guys,

   -

   The function works... All the data is updated as expected. However, when
   I call the function for the second time, it touches the rows that had
   already been touched by the previous call....
   -

   It triplicate ( LIMIT 3 ) the records.

*Question:*

How can I make the function to gets the next 3 rows and not use the same
rows that have been used before?

Function updated:

CREATE or REPLACE FUNCTION function_data_1()
RETURNS SETOF bigint AS $$
declare
        row record;
BEGIN
-- copying the data to the backup table (not the blobs)-- Limiting in
5000 rows each callFOR row IN EXECUTE '
            SELECT
                    t1.file_id
            FROM
                    table1 t1
            JOIN
                    table3 t3 ON t3.file_id = t1.file_id
            ORDER BY 1 LIMIT 3 '
LOOP
-- Creating the backup table with the essential dataINSERT INTO table2
(note_id, size, file_id, full_path)
    (
            SELECT
                    t1.note_id,
                    t1.size,
                    t1.file_id,
                    t1.full_path
            FROM
                    table1 t1
            JOIN
                    table3 t3 ON t3.file_id = t1.file_id
            WHERE
                    t1.file_id = row.file_id
    );
-- copying the blobs to the table above table2
        UPDATE junk.table2 t2 SET data =
        (
            SELECT
                    o1.data
            FROM
                    original_table1_b o1
            JOIN
                    table3 t3 ON t3.file_id = o1.file_id
            WHERE
                    t3.migrated = 0
            AND
                    t2.file_id = o1.file_id
            AND
                    o1.file_id = row.file_id
        )
        WHERE t2.file_id = row.file_id;
-- updating the migrated column from 0 to 1
        UPDATE
                table3 t2
        SET
                migrated = 1
        WHERE
                t2.file_id = row.file_id
        AND
                migrated = 0;
-- set the blobs as null
        UPDATE
                original_table1_b o1
        SET
                data = NULL
        WHERE
                o1.file_id = row.file_id;END LOOP;
END
$$ language 'plpgsql';

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