pg_last_notice() returns the last notice message from the PostgreSQL server specified by connection. The PostgreSQL server sends notice messages in several cases, e.g. if the transactions can't be continued. With pg_last_notice(), you can avoid issuing useless queries, by checking whether the notice is related to the transaction or not.
This function is EXPERIMENTAL and it is not fully implemented yet. pg_last_notice() was added in PHP 4.0.6. However, PHP 4.0.6 has problem with notice message handling. Use of the PostgreSQL module with PHP 4.0.6 is not recommended even if you are not using pg_last_notice().
This function is fully implemented in PHP 4.3.0. PHP earlier than PHP 4.3.0 ignores database connection parameter.
Notice message tracking can be set to optional by setting 1 for pgsql.ignore_notice ini from PHP 4.3.0.
Notice message logging can be set to optional by setting 0 for pgsql.log_notice ini from PHP 4.3.0. Unless pgsql.ignore_notice is set to 0, notice message cannot be logged.