Can I ask Postgresql to ignore errors within a transaction

Question

I use Postgresql with the PostGIS extensions for ad-hoc spatial analysis. I generally construct and issue SQL queries by hand from within psql. I always wrap an analysis session within a transaction, so if I issue a destructive query I can roll it back.

However, when I issue a query that contains an error, it cancels the transaction. Any further queries elicit the following warning:

ERROR: current transaction is aborted, commands ignored until end of transaction block

Is there a way I can turn this behaviour off? It is tiresome to rollback the transaction and rerun previous queries every time I make a typo.

Answer 1

No, there is no way to turn this off. An error implicitly aborts the transaction for you, so you must rollback and try again.

Answer 2

It's possible to write a function that takes a string argument, executes it, and uses an exception clause in order to not abort your transaction, but it's a huge pain to then have to call that function for each statement you wish to execute.

Answer 3

Switching that off is not possible however you can use something different. There is something like savepoint:

http://www.postgresql.org/docs/8.4/interactive/sql-savepoint.html

so you can rollback your transaction to some earlier point without rolling black the whole transaction.

Answer 4

(UPDATE: No need to to this by hand, I asked in the postgresql mailing lists, and it turned that this behaviour is already implemented, by the ON_ERROR_ROLLBACK set in the psql client)

To elaborate on Simon's answer (+1) , in your scenario you could rutinarily add a savepoint after each interactive query, always with the same name (it ovewrites the previous if the query is succesfull). In the case of error, you go back to the last saved one and continue from there.

An example of this working pattern:

db=# select * from test_gral ;
 i |  t   |  n
---+------+------
 1 | text | 10.0
(1 row)

db=# begin;
BEGIN
db=#  insert into test_gral values (2,'xx',20); savepoint sp;
INSERT 0 1
SAVEPOINT
db=#  insert into test_gral values (3,'xx',30); savepoint sp;
INSERT 0 1
SAVEPOINT
db=#  insert into test_gralxx values (4,'xx',40); savepoint sp;
ERROR:  relation "test_gralxx" does not exist
LINE 1: insert into test_gralxx values (4,'xx',40);
                    ^
ERROR:  current transaction is aborted, commands ignored until end of transaction block
db=# ROLLBACK TO SAVEPOINT sp;
ROLLBACK
db=#  insert into test_gral values (4,'xx',40); savepoint sp;
INSERT 0 1
SAVEPOINT
db=# commit;
COMMIT
db=# select * from test_gral ;
 i |  t   |  n
---+------+------
 1 | text | 10.0
 2 | xx   |   20
 3 | xx   |   30
 4 | xx   |   40
(4 rows)