Minimise PHP PDO network transfer data in transit to MySQL - php

Question

Assuming a target table like this:
CREATE TABLE mysql_mytable (
myint INT,
mytinyint TINYINT,
mydecimal DECIMAL(10,2),
mydatetime DATETIME, mydate DATE
)
And the following code with multiple test cases:
$mysql_pdo = new PDO("mysql:...", ..., [
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);
foreach ([
'myint' => [
'a' => [PDO::PARAM_STR, "1048575"],
'b' => [PDO::PARAM_STR, 1048575],//same as previous?
'c' => [PDO::PARAM_STR, dechex(1048575), 'UNHEX(?)'],//"FFFFF"
'e' => [PDO::PARAM_INT, 1048575],//fewest as 4 byte int?
'f' => [PDO::PARAM_INT, "1048575"],//same as previous?
],
'mytinyint' => [
'a' => [PDO::PARAM_STR, "255"],
'b' => [PDO::PARAM_STR, 255],//same as previous?
'c' => [PDO::PARAM_STR, dechex(255), 'UNHEX(?)'],//"FF" fewest bytes as VARCHAR?
'e' => [PDO::PARAM_INT, 255],
'f' => [PDO::PARAM_INT, "255"],//same as previous?
],
'mydecimal' => [//PDO::PARAM_INT cannot be used correctly for decimals?
'a' => [PDO::PARAM_STR, "32000000.00"],
'b' => [PDO::PARAM_STR, "3.2e7"],//fewest bytes as VARCHAR?
],
'mydatetime' => [
'a' => [PDO::PARAM_STR, "2021-05-10 09:09:39"],
'c' => [PDO::PARAM_STR, strtotime("2021-05-10 09:09:39")],
'd' => [PDO::PARAM_INT, strtotime("2021-05-10 09:09:39")],//fewest as 4 byte int?
],
'mydate' => [
'a' => [PDO::PARAM_STR, "2021-05-10"],
'c' => [PDO::PARAM_STR, strtotime("2021-05-10")],
'd' => [PDO::PARAM_INT, strtotime("2021-05-10")],//fewest as 4 byte int?
]
] as $col => $tests) {
foreach ($tests as $case_label => $test) {
list($type, $value) = $test;
$mark = isset($test[2]) ? $test[2] : '?';
$stmt = $mysql_pdo->prepare('INSERT INTO mysql_mytable ({$col}) VALUES ({$mark})');
$stmt->bindValue(1, $value, $type);
$stmt->execute();
}
}
I have spent a lot of time optimizing the disk space used on the table - but there is an ungodly amount of data going to a non-local MySQL instance. There are many columns and many rows... the above is just to show certain groups and options within... this really is import - and yes I'm accounting for making the insert efficient in therms of disable key checks, indexes, etc. I repeat this are example with example code and I'm asking for help to minimise the amount of data sent to the remote MySQL instance... yes it is a huge amount of data and yes the connection is slow enough and the process time critical enough that it matters.
Which, by column/test group, would result in the smallest number of bytes transfered over the network to the MySQL database?
Is there any method to limit the data in using PDO in a different way or not using PDO at all?

Answer 1

Integers are more compact than the equivalent value in a string, regardless of whether it's in decimal or hex.
The decimal value 1048575 requires 7 characters, and the hex value FFFFF takes 5 characters. Whereas the integer uses only 4 bytes.
Also consider whether you have PDO::ATTR_EMULATE_PREPARES enabled. That will defeat the use of integer parameters, because the string value will be interpolated into the query string instead of sent separately as a real parameter.
Speaking for myself, I am not concerned about network transfer for simple data types. Networks are fast enough that the transfer time is negligible compared to the query execution time. Perhaps if you're transferring big BLOB/TEXT content around, or if you are bulk-loading millions of rows, but usually the difference between 4 bytes and 5-8 bytes for an individual integer is not going to solve any performance bottlenecks.