Description:
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Cannot use SAVEPOINTs to recover from errors/exceptions in a transaction.

This method of wrapping multiple statements in a transaction, one or more of which can fail without aborting the transaction is outlined here : http://wiki.postgresql.org/wiki/Transactions_recovering_failures_in_scripts

Test script:
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$dbconn = pg_connect("dbname=test") or die("Could not connect");

$query = "BEGIN;
CREATE TABLE mytable(id INT CHECK (id < 5));
SAVEPOINT savepoint1;
INSERT INTO mytable VALUES (8);
RELEASE savepoint1;
SAVEPOINT savepoint1;
ROLLBACK TO savepoint1;
RELEASE savepoint1;
SAVEPOINT savepoint1;
INSERT INTO mytable VALUES (1);
RELEASE savepoint1;
SAVEPOINT savepoint1;
ROLLBACK TO savepoint1;
RELEASE savepoint1;
COMMIT;";

pg_query($dbconn, $query);
echo pg_last_error();

Expected result:
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The query should the table, fail the first insert, rollback, second insert succeeds then commits.  This is what the SQL will do when put into psql (postgresql console).

Actual result:
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Transaction fails entirely on the first check violation and does not continue:

ERROR: new row for relation "mytable" violates check constraint "mytable_id_check"