Statistics

MySQL Native Driver contains support for gathering statistics on the communication between the client and the server. The statistics gathered are of two main types:

• Client statistics
• Connection statistics

When using the mysqli extension, these statistics can be obtained through two API calls:

• mysqli_get_client_stats()
• mysqli_get_connection_stats()

Retrieving statistics

Client statistics can be retrieved by calling the mysqli_get_client_stats() function.

Connection statistics can be retrieved by calling the mysqli_get_connection_stats() function.

Both functions return an associative array, where the name of a statistic is the key for the corresponding statistical data.

MySQL Native Driver Statistics

Most statistics are associated to a connection, but some are associated to the process in which case this will be mentioned.

The following statistics are produced by the MySQL Native Driver:

bytes_sent

Number of bytes sent from PHP to the MySQL server.

bytes_received

Number of bytes received from the MySQL server.

packets_sent

Number of packets sent by the MySQL Client Server protocol.

packets_received

Number of packets received from the MySQL Client Server protocol.

protocol_overhead_in

MySQL Client Server protocol overhead in bytes for incoming traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_in = packets_received * 4

protocol_overhead_out

MySQL Client Server protocol overhead in bytes for outgoing traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_out = packets_received * 4

bytes_received_ok_packet

Total size of bytes of MySQL Client Server protocol OK packets received. OK packets can contain a status message. The length of the status message can vary and thus the size of an OK packet is not fixed.

Note

The total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).

packets_received_ok

Number of MySQL Client Server protocol OK packets received.

bytes_received_eof_packet

Total size in bytes of MySQL Client Server protocol EOF packets received. EOF can vary in size depending on the server version. Also, EOF can transport an error message.

packets_received_eof

Number of MySQL Client Server protocol EOF packets.

Like with other packet statistics the number of packets will be increased even if PHP does not receive the expected packet but, for example, an error message.

bytes_received_rset_header_packet

Total size in bytes of MySQL Client Server protocol result set header packets. The size of the packets varies depending on the payload (LOAD LOCAL INFILE, INSERT, UPDATE, SELECT, error message).

packets_received_rset_header

Number of MySQL Client Server protocol result set header packets.

bytes_received_rset_field_meta_packet

Total size in bytes of MySQL Client Server protocol result set metadata (field information) packets. Of course the size varies with the fields in the result set. The packet may also transport an error or an EOF packet in case of COM_LIST_FIELDS.

packets_received_rset_field_meta

Number of MySQL Client Server protocol result set metadata (field information) packets.

bytes_received_rset_row_packet

Total size in bytes of MySQL Client Server protocol result set row data packets. The packet may also transport an error or an EOF packet. One can compute the number of error and EOF packets by subtracting rows_fetched_from_server_normal and rows_fetched_from_server_ps from bytes_received_rset_row_packet.

packets_received_rset_row

Number of MySQL Client Server protocol result set row data packets.

bytes_received_prepare_response_packet

Total size in bytes of MySQL Client Server protocol OK for Prepared Statement Initialization packets (prepared statement init packets). The packet may also transport an error. The packet size depends on the MySQL version.

packets_received_prepare_response

Number of MySQL Client Server protocol OK for Prepared Statement Initialization packets (prepared statement init packets).

bytes_received_change_user_packet

Total size in bytes of MySQL Client Server protocol COM_CHANGE_USER packets. The packet may also transport an error or EOF.

packets_received_change_user

Number of MySQL Client Server protocol COM_CHANGE_USER packets.

packets_sent_command

Number of MySQL Client Server protocol commands sent from PHP to MySQL.

There is no way to know which specific commands and how many of them have been sent.

bytes_received_real_data_normal

Number of bytes of payload fetched by the PHP client from mysqlnd using the text protocol.

This is the size of the actual data contained in result sets that do not originate from prepared statements and which have been fetched by the PHP client.

Note that although a full result set may have been pulled from MySQL by mysqlnd, this statistic only counts actual data pulled from mysqlnd by the PHP client.

An example of a code sequence that will increase the value is as follows:

phpCopy

$mysqli = new mysqli();
$res = $mysqli->query("SELECT 'abc'");
$res->fetch_assoc();
$res->close();

Every fetch operation will increase the value.

However, the statistic will not be increased if the result set is only buffered on the client, but not fetched, such as in the following example:

phpCopy

$mysqli = new mysqli();
$res = $mysqli->query("SELECT 'abc'");
$res->close();

bytes_received_real_data_ps

Number of bytes of the payload fetched by the PHP client from mysqlnd using the prepared statement protocol.

This is the size of the actual data contained in result sets that originate from prepared statements and which have been fetched by the PHP client.

The value will not be increased if the result set is not subsequently read by the PHP client.

Note that although a full result set may have been pulled from MySQL by mysqlnd, this statistic only counts actual data pulled from mysqlnd by the PHP client.

See also bytes_received_real_data_normal.

result_set_queries

Number of queries that have generated a result set. Examples of queries that generate a result set: SELECT, SHOW.

The statistic will not be incremented if there is an error reading the result set header packet from the line.

Note

This statistic can be used as an indirect measure for the number of queries PHP has sent to MySQL. This could help identifying a client that causes a high database load.

non_result_set_queries

Number of queries that did not generate a result set. Examples of queries that do not generate a result set: INSERT, UPDATE, LOAD DATA.

The statistic will not be incremented if there is an error reading the result set header packet from the line.

no_index_used

Number of queries that have generated a result set but did not use an index. (See also the mysqld start option --log-queries-not-using-indexes).

Note

Those queries can be reported via an exception by calling mysqli_report(MYSQLI_REPORT_INDEX);. It is possible to have them be reported via a warning instead by calling mysqli_report(MYSQLI_REPORT_INDEX ^ MYSQLI_REPORT_STRICT);.

bad_index_used

Number of queries that have generated a result set and did not use a good index. (See also the mysqld start option --log-slow-queries).

slow_queries

SQL statements that took more than long_query_time seconds to execute and required at least min_examined_row_limit rows to be examined.

Caution

Not reported through mysqli_report().

buffered_sets

Number of buffered result sets returned by normal (i.e. not via a prepared statement) queries.

Examples of API calls that will buffer result sets on the client:

• mysqli_query()
• mysqli_store_result()
• mysqli_stmt_get_result()

unbuffered_sets

Number of unbuffered result sets returned by normal (i.e. not via a prepared statement) queries.

Examples of API calls that will not buffer result sets on the client:

• mysqli_use_result()

ps_buffered_sets

Number of buffered result sets returned by prepared statements.

Examples of API calls that will buffer result sets on the client:

• mysqli_stmt_store_result()

ps_unbuffered_sets

Number of unbuffered result sets returned by prepared statements.

By default prepared statements are unbuffered, thus most prepared statements will be accounted in this statistic.

flushed_normal_sets

Number of result sets returned by normal (i.e. not via a prepared statement) queries with unread data that have been silently flushed.

Note

Flushing happens only with unbuffered result sets.

Unbuffered result sets must be fetched completely before a new query can be run on the connection otherwise MySQL will throw an error. If the application does not fetch all rows from an unbuffered result set, mysqlnd does implicitly fetch the result set to clear the line.

See also rows_skipped_normal, rows_skipped_ps.

Some possible causes for an implicit flush:

• Faulty client application
• Client stopped reading after it found what it was looking for but has made MySQL calculate more records than needed
• Client application has stopped unexpectedly

flushed_ps_sets

Number of result sets from prepared statements with unread data that have been silently flushed.

ps_prepared_never_executed

Number of statements prepared but never executed.

ps_prepared_once_executed

Number of prepared statements executed only once.

rows_fetched_from_server_normal

rows_fetched_from_server_ps

Total number of result set rows fetched from the server. This includes the rows which were not read by the client but had been implicitly fetched due to flushed unbuffered result sets.

See also packets_received_rset_row.

rows_buffered_from_client_normal

Total number of buffered rows originating from a normal query.

This is the number of rows that have been fetched from MySQL and buffered on client.

Examples of queries that will buffer results:

• mysqli_query()
• mysqli_store_result()

rows_buffered_from_client_ps

Same as rows_buffered_from_client_normal but for prepared statements.

rows_fetched_from_client_normal_buffered

Total number of rows fetched by the client from a buffered result set created by a normal query.

rows_fetched_from_client_ps_buffered

Total number of rows fetched by the client from a buffered result set created by a prepared statement.

rows_fetched_from_client_normal_unbuffered

Total number of rows fetched by the client from an unbuffered result set created by a normal query.

rows_fetched_from_client_ps_unbuffered

Total number of rows fetched by the client from an unbuffered result set created by a prepared statement.

rows_fetched_from_client_ps_cursor

Total number of rows fetch by the client from a cursor created by a prepared statement.

rows_skipped_normal

rows_skipped_ps

Reserved for future use (currently not supported).

copy_on_write_saved

copy_on_write_performed

This is a process level scope statistic.

With mysqlnd, variables returned by the extensions point into mysqlnd internal network result buffers. If the data are not changed, the fetched data is kept only once in memory. However, any modification to the data will require mysqlnd to perform a copy-on-write operation.

explicit_free_result

implicit_free_result

This is a connection and process level scope statistic.

Total number of freed result sets.

proto_text_fetched_null

Total number of columns of type MYSQL_TYPE_NULL fetched from a normal query (MySQL text protocol).

proto_binary_fetched_null

Total number of columns of type MYSQL_TYPE_NULL fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_bit

Total number of columns of type MYSQL_TYPE_BIT fetched from a normal query (MySQL text protocol).

proto_binary_fetched_bit

Total number of columns of type MYSQL_TYPE_BIT fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_tinyint

Total number of columns of type MYSQL_TYPE_TINY fetched from a normal query (MySQL text protocol).

proto_binary_fetched_tinyint

Total number of columns of type MYSQL_TYPE_TINY fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_short

Total number of columns of type MYSQL_TYPE_SHORT fetched from a normal query (MySQL text protocol).

proto_binary_fetched_short

Total number of columns of type MYSQL_TYPE_SHORT fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_int24

Total number of columns of type MYSQL_TYPE_INT24 fetched from a normal query (MySQL text protocol).

proto_binary_fetched_int24

Total number of columns of type MYSQL_TYPE_INT24 fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_int

Total number of columns of type MYSQL_TYPE_LONG fetched from a normal query (MySQL text protocol).

proto_binary_fetched_int

Total number of columns of type MYSQL_TYPE_LONG fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_bigint

Total number of columns of type MYSQL_TYPE_LONGLONG fetched from a normal query (MySQL text protocol).

proto_binary_fetched_bigint

Total number of columns of type MYSQL_TYPE_LONGLONG fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_decimal

Total number of columns of type MYSQL_TYPE_DECIMAL, or MYSQL_TYPE_NEWDECIMAL fetched from a normal query (MySQL text protocol).

proto_binary_fetched_decimal

Total number of columns of type MYSQL_TYPE_DECIMAL, or MYSQL_TYPE_NEWDECIMAL fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_float

Total number of columns of type MYSQL_TYPE_FLOAT fetched from a normal query (MySQL text protocol).

proto_binary_fetched_float

Total number of columns of type MYSQL_TYPE_FLOAT fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_double

Total number of columns of type MYSQL_TYPE_DOUBLE fetched from a normal query (MySQL text protocol).

proto_binary_fetched_double

Total number of columns of type MYSQL_TYPE_DOUBLE fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_date

Total number of columns of type MYSQL_TYPE_DATE, or MYSQL_TYPE_NEWDATE fetched from a normal query (MySQL text protocol).

proto_binary_fetched_date

Total number of columns of type MYSQL_TYPE_DATE, or MYSQL_TYPE_NEWDATE fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_year

Total number of columns of type MYSQL_TYPE_YEAR fetched from a normal query (MySQL text protocol).

proto_binary_fetched_year

Total number of columns of type MYSQL_TYPE_YEAR fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_time

Total number of columns of type MYSQL_TYPE_TIME fetched from a normal query (MySQL text protocol).

proto_binary_fetched_time

Total number of columns of type MYSQL_TYPE_TIME fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_datetime

Total number of columns of type MYSQL_TYPE_DATETIME fetched from a normal query (MySQL text protocol).

proto_binary_fetched_datetime

Total number of columns of type MYSQL_TYPE_DATETIME fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_timestamp

Total number of columns of type MYSQL_TYPE_TIMESTAMP fetched from a normal query (MySQL text protocol).

proto_binary_fetched_timestamp

Total number of columns of type MYSQL_TYPE_TIMESTAMP fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_string

Total number of columns of type MYSQL_TYPE_STRING, MYSQL_TYPE_VARSTRING, or MYSQL_TYPE_VARCHAR fetched from a normal query (MySQL text protocol).

proto_binary_fetched_string

Total number of columns of type MYSQL_TYPE_STRING, MYSQL_TYPE_VARSTRING, or MYSQL_TYPE_VARCHAR fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_blob

Total number of columns of type MYSQL_TYPE_TINY_BLOB, MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, or MYSQL_TYPE_BLOB fetched from a normal query (MySQL text protocol).

proto_binary_fetched_blob

Total number of columns of type MYSQL_TYPE_TINY_BLOB, MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, or MYSQL_TYPE_BLOB fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_enum

Total number of columns of type MYSQL_TYPE_ENUM fetched from a normal query (MySQL text protocol).

proto_binary_fetched_enum

Total number of columns of type MYSQL_TYPE_ENUM fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_set

Total number of columns of type MYSQL_TYPE_SET fetched from a normal query (MySQL text protocol).

proto_binary_fetched_set

Total number of columns of type MYSQL_TYPE_SET fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_geometry

Total number of columns of type MYSQL_TYPE_GEOMETRY fetched from a normal query (MySQL text protocol).

proto_binary_fetched_geometry

Total number of columns of type MYSQL_TYPE_GEOMETRY fetched from a prepared statement (MySQL binary protocol).

proto_text_fetched_other

Total number of columns of types MYSQL_TYPE_* not listed previously fetched from a normal query (MySQL text protocol).

Note

In theory, this should always be 0.

proto_binary_fetched_other

Total number of columns of type MYSQL_TYPE_* not listed previously fetched from a prepared statement (MySQL binary protocol).

Note

In theory, this should always be 0.

connect_success

Total number of successful connection attempts.

Note

connect_success holds the sum of successful persistent and non-persistent connection attempts. Therefore, the number of successful non-persistent connection attempts is connect_success - pconnect_success.

pconnect_success

Total number of successful persistent connection attempts.

connect_failure

Total number of failed connection attempts.

reconnect

This is a process level scope statistic.

active_connections

This is a process level scope statistic.

Total number of active persistent and non-persistent connections.

Note

The total number of active non-persistent connections is active_connections - active_persistent_connections.

active_persistent_connections

This is a process level scope statistic.

Total number of active persistent connections.

explicit_close

Total number of explicitly closed connections.

Examples of code snippets that cause an explicit close

• phpCopy

  $link = new mysqli(/* ... */);
  $link->close(/* ... */);

• phpCopy

  $link = new mysqli(/* ... */);
  $link->connect(/* ... */);

implicit_close

Total number of implicitly closed connections.

Examples of code snippets that cause an implicit close

• phpCopy

  $link = new mysqli(/* ... */);
  $link->real_connect(/* ... */);

• phpCopy

  unset($link)

• Persistent connection: pooled connection has been created with real_connect and there may be unknown options set - close implicitly to avoid returning a connection with unknown options
• Persistent connection: ping/change_user fails and ext/mysqli closes the connection
• End of script execution: close connections that have not been closed by the user

disconnect_close

Connection failures indicated by the C API call mysql_real_connect during an attempt to establish a connection.

in_middle_of_command_close

This is a process level scope statistic.

A connection has been closed in the middle of a command execution (outstanding result sets not fetched, after sending a query and before retrieving an answer, while fetching data, while transferring data with LOAD DATA).

Warning

Unless asynchronous queries are used, this should only happen if the PHP application terminated unexpectedly, and PHP shuts down the connection automatically.

init_command_executed_count

Total number of init command executions. For example: mysqli_options(MYSQLI_INIT_COMMAND , $value).

The number of successful executions is init_command_executed_count - init_command_failed_count.

init_command_failed_count

Total number of failed init commands.

com_quit

com_init_db

com_query

com_field_list

com_create_db

com_drop_db

com_refresh

com_shutdown

com_statistics

com_process_info

com_connect

com_process_kill

com_debug

com_ping

com_time

com_delayed_insert

com_change_user

com_binlog_dump

com_table_dump

com_connect_out

com_register_slave

com_stmt_prepare

com_stmt_execute

com_stmt_send_long_data

com_stmt_close

com_stmt_reset

com_stmt_set_option

com_stmt_fetch

com_daemon

Total number of attempts to send a certain COM_* command from PHP to MySQL.

The statistics are incremented after checking the line and immediately before sending the corresponding MySQL client server protocol packet.

Caution

If MySQLnd fails to send the packet over the wire the statistics will not be decremented. In case of a failure MySQLnd emits a PHP warning Error while sending %s packet. PID=%d.

Usage examples

• Check if PHP sends certain commands to MySQL, for example, check if a client sends COM_PROCESS_KILL
• Calculate the average number of prepared statement executions by comparing COM_EXECUTE with COM_PREPARE
• Check if PHP has run any non-prepared SQL statements by checking if COM_QUERY is zero
• Identify PHP scripts that run an excessive number of SQL statements by checking COM_QUERY and COM_EXECUTE

explicit_stmt_close

implicit_stmt_close

This is a process level scope statistic.

Total number of closed prepared statements.

Note

A prepared statement is always explicitly closed. The only time it's closed implicitly is when preparing it fails.

mem_emalloc_count

mem_emalloc_ammount

mem_ecalloc_count

mem_ecalloc_ammount

mem_realloc_count

mem_realloc_ammount

mem_efree_count

mem_malloc_count

mem_malloc_ammount

mem_calloc_count

mem_calloc_ammount

mem_ealloc_count

mem_ealloc_ammount

mem_free_count

This is a process level scope statistic.

Memory management calls.

command_buffer_too_small

Number of network command buffer extensions while sending commands from PHP to MySQL.

MySQLnd allocates an internal command/network buffer of mysqlnd.net_cmd_buffer_size bytes for every connection.

If a MySQL Client Server protocol command, e.g. COM_QUERY (normal query), does not fit into the buffer, MySQLnd will grow the buffer to what is needed for sending the command. Whenever the buffer gets extended for one connection command_buffer_too_small will be incremented by one.

If MySQLnd has to grow the buffer beyond its initial size of mysqlnd.net_cmd_buffer_size bytes for almost every connection, considerations to increase the default size should be made to avoid re-allocations.

connection_reused

The total number of times a persistent connection has been reused.