Will using UNIX_TIMESTAMP() slow down my INSERT query

Question

I have to make over 20 insert statements in one go. I am using UNIX_TIMESTAMP() there to insert seconds since epoch in my time columns.

My php timezone is UTC

So should i use $time = time() for inserting values or UNIX_TIMESTAMP() is fine.

Answer 1

time()

time — Return current Unix timestamp

UNIX_TIMESTAMP()

If called with no argument, returns a Unix timestamp (seconds since '1970-01-01 00:00:00' UTC) as an unsigned integer.

Looks to me they are the same thing. So I highly doubt there would be a difference noticable enough to warrant choosing one over the other just for optimization. Choose whichever makes your code easier to read and understand would be my suggestion. MySQL can handle a very large number of actions at once so doing something trivial like getting the timestamp would be almost instantaneous.

Answer 2

Whatever you do, decide based on functionality, not on efficiency; you probably won't even feel the difference, even with 100 insert statements.

Which option to choose should depend on your functional requirements:

1. If you must absolutely be certain that the value for each statement is the same, you should "cache" the value of time() and use that to do the insert; btw, this can be done either in MySQL or PHP (see below).

2. For all else, choose whatever you like.

If you are inserting multiple records, I hope you would consider prepared statements; doing so may actually speed up the insert statements in a more significant way, mainly thanks to the less amount of data that has to travel between code and database. For example:

SET @time = UNIX_TIMESTAMP();
PREPARE stmt FROM 'INSERT INTO mytable VALUES (@time)';
EXECUTE stmt;
EXECUTE stmt;
EXECUTE stmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;