Re: Lock-ups with multi-threading and psycopg 2.0.11

Richard Davies <[email protected]>
Newsgroups gmane.comp.python.db.psycopg.devel
Message-ID <[email protected]> 
> OK, I've managed to generate the simple test case, which is a big step
> forward!

And now I've just discovered the PSYCOPG_DEBUG option too.

Here are a few different traces of the last lines before a lockup, running
with Python 2.5.2, PostgreSQL 8.1.4 and Psycopg2 2.0.12 with PSYCOPG_DEBUG:

after <Tester(Thread-2, started)>
[20525] _psyco_curs_prefetch: result = 0
[20525] psyco_curs_close: cursor at 0xf7c1e48c closed
[20525] psyco_conn_cursor: new cursor for connection at 0xf7bbe2fc
[20525] psyco_conn_cursor:     parameters: name = (null)
[20525] cursor_setup: init cursor object at 0xf7c1e41c
[20525] cursor_setup: parameters: name = (null), conn = 0xf7bbe2fc
[20525] cursor_setup: good cursor object at 0xf7c1e41c, refcnt = 1
[20525] psyco_conn_cursor: new cursor at 0xf7c1e41c: refcnt = 1
[20525] cursor_dealloc: deleted cursor object at 0xf7c1e48c, refcnt = 0
before <Tester(Thread-2, started)>
[20525] pq_execute: entering syncronous DBAPI compatibility mode
[20525] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20525] pq_fetch: data from a SELECT (got tuples)
[20525] _pq_fetch_tuples: looking for cast 25:
[20525] _pq_fetch_tuples:     per-connection dict: (nil)
[20525] _pq_fetch_tuples:     global dict: 0xf7b593ec
[20525] _pq_fetch_tuples: using cast at 0xf7b593ec (STRING) for type 25
[20525] _pq_fetch_tuples: looking for cast 25:
[20525] _pq_fetch_tuples:     per-connection dict: (nil)
[20525] _pq_fetch_tuples:     global dict: 0xf7b593ec
[20525] _pq_fetch_tuples: using cast at 0xf7b593ec (STRING) for type 25
[20525] pq_fetch: fetching done; check for critical errors
[20525] psyco_curs_execute: res = 1, pgres = 0x959a858
after <Tester(Thread-1, started)>
[20525] _psyco_curs_prefetch: result = 0
[20525] psyco_curs_close: cursor at 0xf7c1e72c closed
[20525] psyco_conn_cursor: new cursor for connection at 0xf7bbe2fc
[20525] psyco_conn_cursor:     parameters: name = (null)
[20525] cursor_setup: init cursor object at 0xf7c1e48c
[20525] cursor_setup: parameters: name = (null), conn = 0xf7bbe2fc
[20525] cursor_setup: good cursor object at 0xf7c1e48c, refcnt = 1
[20525] psyco_conn_cursor: new cursor at 0xf7c1e48c: refcnt = 1
[20525] cursor_dealloc: deleted cursor object at 0xf7c1e72c, refcnt = 0
before <Tester(Thread-1, started)>
[20525] psyco_curs_execute: starting execution of new query
[20525] curs_execute: pg connection at 0x95d8a28 OK
[20525] pq_begin_locked: pgconn = 0x95d8a28, isolevel = 1, status = 2
[20525] pq_begin_locked: transaction in progress
[20525] pq_execute: executing SYNC query:
[20525]     select * from test
[20525] psyco_curs_execute: starting execution of new query
[20525] curs_execute: pg connection at 0x95d8a28 OK
[20525] pq_execute: entering syncronous DBAPI compatibility mode
[20525] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20525] pq_fetch: data from a SELECT (got tuples)
[20525] pq_begin_locked: pgconn = 0x95d8a28, isolevel = 1, status = 2
[20525] pq_begin_locked: transaction in progress
[20525] pq_execute: executing SYNC query:
[20525]     select * from test
[20525] pq_execute: entering syncronous DBAPI compatibility mode
[20525] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20525] pq_fetch: data from a SELECT (got tuples)
[20525] _pq_fetch_tuples: looking for cast 25:
[20525] _pq_fetch_tuples:     per-connection dict: (nil)
[20525] _pq_fetch_tuples:     global dict: 0xf7b593ec
[20525] _pq_fetch_tuples: using cast at 0xf7b593ec (STRING) for type 25
[20525] _pq_fetch_tuples: looking for cast 25:
[20525] _pq_fetch_tuples:     per-connection dict: (nil)
[20525] _pq_fetch_tuples:     global dict: 0xf7b593ec
[20525] _pq_fetch_tuples: using cast at 0xf7b593ec (STRING) for type 25
[20525] pq_fetch: fetching done; check for critical errors



after <Tester(Thread-1, started)>
[20655] _psyco_curs_prefetch: result = 0
[20655] psyco_curs_close: cursor at 0xf7c2c41c closed
[20655] psyco_conn_cursor: new cursor for connection at 0xf7bcc2fc
[20655] psyco_conn_cursor:     parameters: name = (null)
[20655] cursor_setup: init cursor object at 0xf7c2c72c
[20655] cursor_setup: parameters: name = (null), conn = 0xf7bcc2fc
[20655] cursor_setup: good cursor object at 0xf7c2c72c, refcnt = 1
[20655] psyco_conn_cursor: new cursor at 0xf7c2c72c: refcnt = 1
[20655] cursor_dealloc: deleted cursor object at 0xf7c2c41c, refcnt = 0
before <Tester(Thread-1, started)>
[20655] psyco_curs_execute: starting execution of new query
[20655] curs_execute: pg connection at 0x8916a28 OK
[20655] pq_begin_locked: pgconn = 0x8916a28, isolevel = 1, status = 2
[20655] pq_begin_locked: transaction in progress
[20655] pq_execute: executing SYNC query:
[20655]     select * from test
[20655] pq_execute: entering syncronous DBAPI compatibility mode
[20655] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20655] pq_fetch: data from a SELECT (got tuples)
[20655] _pq_fetch_tuples: looking for cast 25:
[20655] _pq_fetch_tuples:     per-connection dict: (nil)
[20655] _pq_fetch_tuples:     global dict: 0xf7b673ec
[20655] _pq_fetch_tuples: using cast at 0xf7b673ec (STRING) for type 25
[20655] _pq_fetch_tuples: looking for cast 25:
[20655] _pq_fetch_tuples:     per-connection dict: (nil)
[20655] _pq_fetch_tuples:     global dict: 0xf7b673ec
[20655] _pq_fetch_tuples: using cast at 0xf7b673ec (STRING) for type 25
[20655] pq_fetch: fetching done; check for critical errors
[20655] psyco_curs_execute: res = 1, pgres = 0x8901298
after <Tester(Thread-2, started)>
[20655] _psyco_curs_prefetch: result = 0
[20655] psyco_curs_close: cursor at 0xf7c2c48c closed
[20655] psyco_conn_cursor: new cursor for connection at 0xf7bcc2fc
[20655] psyco_conn_cursor:     parameters: name = (null)
[20655] cursor_setup: init cursor object at 0xf7c2c41c
[20655] cursor_setup: parameters: name = (null), conn = 0xf7bcc2fc
[20655] cursor_setup: good cursor object at 0xf7c2c41c, refcnt = 1
[20655] psyco_conn_cursor: new cursor at 0xf7c2c41c: refcnt = 1
[20655] cursor_dealloc: deleted cursor object at 0xf7c2c48c, refcnt = 0
before <Tester(Thread-2, started)>
[20655] psyco_curs_execute: starting execution of new query
[20655] curs_execute: pg connection at 0x8916a28 OK
[20655] pq_begin_locked: pgconn = 0x8916a28, isolevel = 1, status = 2
[20655] pq_begin_locked: transaction in progress
[20655] pq_execute: executing SYNC query:
[20655]     select * from test
[20655] pq_execute: entering syncronous DBAPI compatibility mode
[20655] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20655] pq_fetch: data from a SELECT (got tuples)



after <Tester(Thread-1, started)>
[20680] _psyco_curs_prefetch: result = 0
[20680] psyco_curs_close: cursor at 0xf7ce772c closed
[20680] psyco_conn_cursor: new cursor for connection at 0xf7c872fc
[20680] psyco_conn_cursor:     parameters: name = (null)
[20680] cursor_setup: init cursor object at 0xf7ce741c
[20680] cursor_setup: parameters: name = (null), conn = 0xf7c872fc
[20680] cursor_setup: good cursor object at 0xf7ce741c, refcnt = 1
[20680] psyco_conn_cursor: new cursor at 0xf7ce741c: refcnt = 1
[20680] cursor_dealloc: deleted cursor object at 0xf7ce772c, refcnt = 0
before <Tester(Thread-1, started)>
[20680] psyco_curs_execute: starting execution of new query
[20680] curs_execute: pg connection at 0x817ba28 OK
[20680] pq_begin_locked: pgconn = 0x817ba28, isolevel = 1, status = 2
[20680] pq_begin_locked: transaction in progress
[20680] pq_execute: executing SYNC query:
[20680]     select * from test
[20680] pq_execute: entering syncronous DBAPI compatibility mode
[20680] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20680] pq_fetch: data from a SELECT (got tuples)
[20680] _pq_fetch_tuples: looking for cast 25:
[20680] _pq_fetch_tuples:     per-connection dict: (nil)
[20680] _pq_fetch_tuples:     global dict: 0xf7c223ec
[20680] _pq_fetch_tuples: using cast at 0xf7c223ec (STRING) for type 25
[20680] _pq_fetch_tuples: looking for cast 25:
[20680] _pq_fetch_tuples:     per-connection dict: (nil)
[20680] _pq_fetch_tuples:     global dict: 0xf7c223ec
[20680] _pq_fetch_tuples: using cast at 0xf7c223ec (STRING) for type 25
[20680] pq_fetch: fetching done; check for critical errors
[20680] psyco_curs_execute: res = 1, pgres = 0x8166308
after <Tester(Thread-2, started)>
[20680] _psyco_curs_prefetch: result = 0
[20680] psyco_curs_close: cursor at 0xf7ce748c closed
[20680] psyco_conn_cursor: new cursor for connection at 0xf7c872fc
[20680] psyco_conn_cursor:     parameters: name = (null)
[20680] cursor_setup: init cursor object at 0xf7ce772c
[20680] cursor_setup: parameters: name = (null), conn = 0xf7c872fc
[20680] cursor_setup: good cursor object at 0xf7ce772c, refcnt = 1
[20680] psyco_conn_cursor: new cursor at 0xf7ce772c: refcnt = 1
[20680] cursor_dealloc: deleted cursor object at 0xf7ce748c, refcnt = 0
before <Tester(Thread-2, started)>
[20680] psyco_curs_execute: starting execution of new query
[20680] curs_execute: pg connection at 0x817ba28 OK
[20680] pq_begin_locked: pgconn = 0x817ba28, isolevel = 1, status = 2
[20680] pq_begin_locked: transaction in progress
[20680] pq_execute: executing SYNC query:
[20680]     select * from test
[20680] pq_execute: entering syncronous DBAPI compatibility mode
[20680] pq_fetch: pgstatus = PGRES_TUPLES_OK
[20680] pq_fetch: data from a SELECT (got tuples)
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