NOT IN with NULLs in the Subquery
A coworker came to me with a perplexing issue. He wanted to know why these two queries were not returning the same results: mysql> SELECT COUNT(*) -> FROM parent -> WHERE id NOT IN (SELECT...
View ArticleINSERT, Don’t DELETE
I’ve been working on a data archival project over the last couple weeks and thought it would be interesting to discuss something a bit counter-intuitive. Absolutes are never true, but when getting rid...
View ArticlePerformance of MySQL Semi-Synchronous Replication Over High Latency Connections
I have seen a few posts on DBA.SE (where I answer a lot of questions) recommending the use of semi-synchronous replication in MySQL 5.5 over a WAN as a way to improve the reliability of replication. My...
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