MySQL

EXPLAIN UPDATE in MySQL 5.6

Xaprb, home of innotop - Tue, 2013-11-26 21:35

I just tried out EXPLAIN UPDATE in MySQL 5.6 and found unexpected results. This query has no usable index: EXPLAIN UPDATE ... WHERE col1 = 9 AND col2 = 'something'\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: foo type: index possible_keys: NULL key: PRIMARY key_len: 55 ref: NULL rows: 51 Extra: Using where

The EXPLAIN output makes it seem like a perfectly fine query, but it’s a full table scan. If I do the old trick of rewriting it to a SELECT I see that: *************************** 1. row *************************** id: 1 select_type: SIMPLE table: foo type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 51 Extra: Using where

Should I file this as a bug? It seems like one to me.

Categories: MySQL

EXPLAIN UPDATE in MySQL 5.6

Xaprb, home of innotop - Tue, 2013-11-26 00:00

I just tried out EXPLAIN UPDATE in MySQL 5.6 and found unexpected results. This query has no usable index:

EXPLAIN UPDATE ... WHERE col1 = 9 AND col2 = 'something'\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: foo type: index possible_keys: NULL key: PRIMARY key_len: 55 ref: NULL rows: 51 Extra: Using where

The EXPLAIN output makes it seem like a perfectly fine query, but it’s a full table scan. If I do the old trick of rewriting it to a SELECT I see that:

*************************** 1. row *************************** id: 1 select_type: SIMPLE table: foo type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 51 Extra: Using where

Should I file this as a bug? It seems like one to me.

Categories: MySQL

Freeing some Velocity videos

Xaprb, home of innotop - Sat, 2013-11-09 17:51

Following my previous post on Velocity videos, I had some private email conversations with good folks at O’Reilly, and a really nice in-person exchange with a top-level person as well. I was surprised to hear them encourage me to publish my videos online freely!

I still believe that nothing substitutes for the experience of attending an O’Reilly conference in-person, but I’ll also be the first to admit that my talks are usually more conceptual and academic than practical, and designed to start a conversation rather than to tell you the Truth According To Baron. Thus, I think they’re worth sharing more widely.

O’Reilly alleviated my concerns about “killing the golden goose,” but I like one person’s take on the cost of O’Reilly’s conferences. “You think education is expensive? Try ignorance.”

I’ll post some of my past talks soon for your enjoyment.

Categories: MySQL

Freeing some Velocity videos

Xaprb, home of innotop - Sat, 2013-11-09 00:00

Following my previous post on Velocity videos, I had some private email conversations with good folks at O’Reilly, and a really nice in-person exchange with a top-level person as well. I was surprised to hear them encourage me to publish my videos online freely!

I still believe that nothing substitutes for the experience of attending an O’Reilly conference in-person, but I’ll also be the first to admit that my talks are usually more conceptual and academic than practical, and designed to start a conversation rather than to tell you the Truth According To Baron. Thus, I think they’re worth sharing more widely.

O’Reilly alleviated my concerns about “killing the golden goose,” but I like one person’s take on the cost of O’Reilly’s conferences. “You think education is expensive? Try ignorance.”

I’ll post some of my past talks soon for your enjoyment.

Categories: MySQL
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