I am running the following script:------------------------------------------>>> import sqlite3>>> import os>>> import time>>> con1 = sqlite3.connect("/tmp/test.db")>>> con2 = sqlite3.connect("/tmp/test.db")>>> con1.set_trace_callback(print)>>> cur = con1.cursor()>>> cur.execute("create table test(a)")create table test(a)<sqlite3.Cursor object at 0x7fb488ddf260>>>> con2.execute("create table test2(a)")<sqlite3.Cursor object at 0x7fb488ddf2d0>>>> cur.execute("insert into test(a) values(1)")BEGIN insert into test(a) values(1)insert into test(a) values(1)<sqlite3.Cursor object at 0x7fb488ddf260>>>> for a in con1.execute("select * from test"):...     print("result:", a)... select * from testresult: (1,)-------------------------------------------As you can see i get duplicate traceback print of the "insert into test(a) values(1)" line. The duplicate print has no effect on the actual db.I have tested this both on python 3.4.3 and 3.6.0a0 on ubuntu14.04

This issue will be resolved when we change the sqlite3_prepare to sqlite3_prepare_v2. So there should be a dependency onissue 9303.

It would be nice to add a test case tohttps://github.com/python/cpython/blob/86a670543ff97d52fd9b8ca0477f8b6d27ee946d/Lib/sqlite3/test/hooks.py#L204 before closing this.

I can work on this.

New changeset0e6cb2ea624570ed08c354f1ed1f595dab4192d6 by Berker Peksag (Aviv Palivoda) in branch 'master':bpo-26187: Test that set_trace_callback() is not called multiple times (GH-461)https://github.com/python/cpython/commit/0e6cb2ea624570ed08c354f1ed1f595dab4192d6

Thanks, Anish and Aviv!