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Displaying posts with tag: histograms (reset)
sysbench Histograms: A Helpful Feature Often Overlooked

In this blog post, I will demonstrate how to run and use sysbench histograms.

One of the features of sysbench that I often I see overlooked (and rarely used) is its ability to produce detailed query response time histograms in addition to computing percentile numbers. Looking at histograms together with throughput or latency over time provides many additional insights into query performance.

Here is how you get detailed sysbench histograms and performance over time:

sysbench --rand-type=uniform --report-interval=1 --percentile=99 --time=300 --histogram --mysql-password=sbtest oltp_point_select --table_size=400000000 run

There are a few command line options to consider:

  • report-interval=1 – prints out the current performance measurements every second, which helps see if …
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Percona Live 2017: Histograms in MySQL and MariaDB

The afternoon at Percona Live 2017 is slipping by quickly, and people are still actively looking for sessions to attend – like the session I just sat in on histograms in MySQL and MariaDB.

Histograms are a type of column statistic that provides more detailed information about data distributions in table columns. A histogram sorts values into buckets.

MariaDB Server has had histograms since MariaDB 10.0. Now, MySQL 8.0 will have them too. This session presented an overview of histogram implementations in MariaDB, MySQL 8.0, and looked at PostgreSQL for comparison. The session covered everything about histograms:

  • Why do query optimizers need histograms
  • What are the costs of collecting and maintaining a …
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