MySQL Forums
Forum List  »  InnoDB

Is MySQL sure about the sequential read is really sequential in SSD
Posted by: haochen he
Date: May 06, 2022 06:55AM

In SSD, overwriting a data file means SSD has to first erase it and then write data. This can change the data layout for the data file.

MySQL has some policies to optimize random IO, e.g., read-ahead (pre-fetching). Read-ahead policy will pre-read the remaining x pages in an extent if prior y pages are read sequentially. From the perspective of MySQL, using consecutive offsets for `pread` can make reads sequential. But I doubt is it true for a SSD.

This point to another important question: does an extent (usually contains 64 pages) in MySQL must represent consecutive space for SSD.

Options: ReplyQuote


Subject
Views
Written By
Posted
Is MySQL sure about the sequential read is really sequential in SSD
541
May 06, 2022 06:55AM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.