Enable caching of results with fetch type PDO::FETCH_COLUMN #126
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This was referenced Dec 6, 2015
mpdude
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Sep 12, 2018
The blob type maps BLOB (and also TEXT) columns to PHP streams. Internally, they use the ParameterType::LARGE_OBJECT (i. e. \PDO::PARAM_LOB) binding type, which suggests that efficient handling of PHP stream resources was intended. However, at least when using the mysqli driver, stream resources passed into insert() or update() are simply cast to strings. As a result, a literal string like "Resource id doctrine#126" will end up in the database. This PR fixes the issue by correctly processing streams in the MysqliStatement when they are passed with the ParameterType::LARGE_OBJECT binding type. It uses the mysqli::send_long_data() method to pass stream data in chunks to the MySQL server, thus keeping the memory footprint low. This method does not (despite claims to the contrary) allow to bypass the max_allowed_package size! The pdo_mysql driver was already capable of handling streams this way. Now this is covered by tests. Helpful documentation: - http://php.net/manual/en/mysqli-stmt.send-long-data.php - http://php.net/manual/en/mysqli-stmt.bind-param.php - see first "Note" - http://php.net/manual/en/pdo.lobs.php - https://blogs.oracle.com/oswald/phps-mysqli-extension:-storing-and-retrieving-blobs Additional notes on MySQL's max_allowed_packet: This change does not not intend to work around the max_allowed_packet setting, and quick tests show that this is not possible: When MySQL is configured to use a low max_allowed_packet value, an error will be triggered stating Parameter of prepared statement which is set through mysql_send_long_data() is longer than 'max_allowed_packet' bytes. Documentation for the underlying mysql_stmt_send_long_data() C API function suggests that max_allowed_packet is always a hard limit. References: - https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-send-long-data.html - https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_max_allowed_packet - https://bugs.mysql.com/bug.php?id=83958 What mysqli::send_long_data() seems to do is that every data chunk of data passed to it is immediately sent out to the network. I have confirmed this using tcpdump, and so the advantage might be that we can keep the memory footprint low on the PHP side while processing streams.
mpdude
added a commit
to mpdude/dbal
that referenced
this pull request
Sep 12, 2018
The blob type maps BLOB (and also TEXT) columns to PHP streams. Internally, they use the ParameterType::LARGE_OBJECT (i. e. \PDO::PARAM_LOB) binding type, which suggests that efficient handling of PHP stream resources was intended. However, at least when using the mysqli driver, stream resources passed into insert() or update() are simply cast to strings. As a result, a literal string like "Resource id doctrine#126" will end up in the database. This PR fixes the issue by correctly processing streams in the MysqliStatement when they are passed with the ParameterType::LARGE_OBJECT binding type. It uses the mysqli::send_long_data() method to pass stream data in chunks to the MySQL server, thus keeping the memory footprint low. This method does not (despite claims to the contrary) allow to bypass the max_allowed_package size! The pdo_mysql driver was already capable of handling streams this way. Now this is covered by tests. Helpful documentation: - http://php.net/manual/en/mysqli-stmt.send-long-data.php - http://php.net/manual/en/mysqli-stmt.bind-param.php - see first "Note" - http://php.net/manual/en/pdo.lobs.php - https://blogs.oracle.com/oswald/phps-mysqli-extension:-storing-and-retrieving-blobs Additional notes on MySQL's max_allowed_packet: This change does not not intend to work around the max_allowed_packet setting, and quick tests show that this is not possible: When MySQL is configured to use a low max_allowed_packet value, an error will be triggered stating Parameter of prepared statement which is set through mysql_send_long_data() is longer than 'max_allowed_packet' bytes. Documentation for the underlying mysql_stmt_send_long_data() C API function suggests that max_allowed_packet is always a hard limit. References: - https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-send-long-data.html - https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_max_allowed_packet - https://bugs.mysql.com/bug.php?id=83958 What mysqli::send_long_data() seems to do is that every data chunk of data passed to it is immediately sent out to the network. I have confirmed this using tcpdump, and so the advantage might be that we can keep the memory footprint low on the PHP side while processing streams.
mpdude
added a commit
to mpdude/dbal
that referenced
this pull request
Sep 17, 2018
The blob type maps BLOB (and also TEXT) columns to PHP streams. Internally, they use the ParameterType::LARGE_OBJECT (i. e. \PDO::PARAM_LOB) binding type, which suggests that efficient handling of PHP stream resources was intended. However, at least when using the mysqli driver, stream resources passed into insert() or update() are simply cast to strings. As a result, a literal string like "Resource id doctrine#126" will end up in the database. This PR fixes the issue by correctly processing streams in the MysqliStatement when they are passed with the ParameterType::LARGE_OBJECT binding type. It uses the mysqli::send_long_data() method to pass stream data in chunks to the MySQL server, thus keeping the memory footprint low. This method does not (despite claims to the contrary) allow to bypass the max_allowed_package size! The pdo_mysql driver was already capable of handling streams this way. Now this is covered by tests. Helpful documentation: - http://php.net/manual/en/mysqli-stmt.send-long-data.php - http://php.net/manual/en/mysqli-stmt.bind-param.php - see first "Note" - http://php.net/manual/en/pdo.lobs.php - https://blogs.oracle.com/oswald/phps-mysqli-extension:-storing-and-retrieving-blobs Additional notes on MySQL's max_allowed_packet: This change does not not intend to work around the max_allowed_packet setting, and quick tests show that this is not possible: When MySQL is configured to use a low max_allowed_packet value, an error will be triggered stating Parameter of prepared statement which is set through mysql_send_long_data() is longer than 'max_allowed_packet' bytes. Documentation for the underlying mysql_stmt_send_long_data() C API function suggests that max_allowed_packet is always a hard limit. References: - https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-send-long-data.html - https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_max_allowed_packet - https://bugs.mysql.com/bug.php?id=83958 What mysqli::send_long_data() seems to do is that every data chunk of data passed to it is immediately sent out to the network. I have confirmed this using tcpdump, and so the advantage might be that we can keep the memory footprint low on the PHP side while processing streams.
mpdude
added a commit
to mpdude/dbal
that referenced
this pull request
Sep 27, 2018
The blob type maps BLOB (and also TEXT) columns to PHP streams. Internally, they use the ParameterType::LARGE_OBJECT (i. e. \PDO::PARAM_LOB) binding type, which suggests that efficient handling of PHP stream resources was intended. However, at least when using the mysqli driver, stream resources passed into insert() or update() are simply cast to strings. As a result, a literal string like "Resource id doctrine#126" will end up in the database. This PR fixes the issue by correctly processing streams in the MysqliStatement when they are passed with the ParameterType::LARGE_OBJECT binding type. It uses the mysqli::send_long_data() method to pass stream data in chunks to the MySQL server, thus keeping the memory footprint low. This method does not (despite claims to the contrary) allow to bypass the max_allowed_package size! The pdo_mysql driver was already capable of handling streams this way. Now this is covered by tests. Helpful documentation: - http://php.net/manual/en/mysqli-stmt.send-long-data.php - http://php.net/manual/en/mysqli-stmt.bind-param.php - see first "Note" - http://php.net/manual/en/pdo.lobs.php - https://blogs.oracle.com/oswald/phps-mysqli-extension:-storing-and-retrieving-blobs Additional notes on MySQL's max_allowed_packet: This change does not not intend to work around the max_allowed_packet setting, and quick tests show that this is not possible: When MySQL is configured to use a low max_allowed_packet value, an error will be triggered stating Parameter of prepared statement which is set through mysql_send_long_data() is longer than 'max_allowed_packet' bytes. Documentation for the underlying mysql_stmt_send_long_data() C API function suggests that max_allowed_packet is always a hard limit. References: - https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-send-long-data.html - https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_max_allowed_packet - https://bugs.mysql.com/bug.php?id=83958 What mysqli::send_long_data() seems to do is that every data chunk of data passed to it is immediately sent out to the network. I have confirmed this using tcpdump, and so the advantage might be that we can keep the memory footprint low on the PHP side while processing streams.
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This should enable caching of results retrieved by PDO::FETCH_COLUMN fetch type.
Before this exception "Invalid fetch-style given for caching result" was raised.