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Search Results for: slow updates

Why “insert … on duplicate key update” May Be Slow, by Incurring Disk Seeks

In my post on June 18th, I explained why the semantics of normal ad-hoc insertions with a primary key are expensive because they require disk seeks on large data sets. I previously explained why it …


A few administrative updates

I wanted to write a few administrative updates in one so I didn’t spam everyone’s feed readers too much. Here we go: We’ve had reports of some lost comments.  We reported this via Twitter a …


Updated msl (microslow) patch, installation walk-through!

For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important …


Tradeoffs: Updates versus Range Queries

Sorry for the delay, now on to range queries and lenient updates. Let’s call them queries and updates, for short. So far, I’ve shown that B-trees (and any of a number of other data structures) …


How Fast Can Updates Run?

Last time, I introduced the notion of strict and lenient updates. Now it’s time to see what the performance characteristics are of each. Just to rehash, we are focusing on the storage engine (a la …


Updates & Discipline

So far, I’ve analyzed point and range queries. Now it’s time to talk about insertions and deletions. We’ll call the combination updates. Updates come in two flavors, and today we’ll cover both. Depending on the …


Looking deeper into InnoDB’s problem with many row versions

A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single …


InnoDB crash recovery speed in MySQL 5.6

It has been a while since I have looked at InnoDB crash recovery. A lot has change in the last few years – we have serious crash recovery performance improvements in MySQL 5.5 and MySQL …


InnoDB’s multi-versioning handling can be Achilles’ heel

I believe InnoDB storage engine architecture is great for a lot of online workloads, however, there are no silver bullets in technology and all design choices have their trade offs. In this blog post I’m …