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The Speed of Time

Brendan Gregg

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. As (C) looked like a kernel rebuild, I started with (D) and (E). ## 5. I also rewrote this in C and called gettimeofday(2) directly: $ cat gettimeofdaybench.c. What on Earth is Ubuntu doing that results in 30% higher CPU time!?

Speed 126
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How to maximize CPU performance for PostgreSQL 12.0 benchmarks on Linux

HammerDB

HammerDB doesn’t publish competitive database benchmarks, instead we always encourage people to be better informed by running their own. So over at Phoronix some database benchmarks were published showing PostgreSQL 12 Performance With AMD EPYC 7742 vs. Intel Xeon Platinum 8280 Benchmarks .

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How to improve Redo, Transaction Log and WAL throughput for HammerDB benchmarks

HammerDB

If you are new to running Oracle, SQL Server, MySQL and PostgreSQL TPC-C workloads with HammerDB and have needed to investigate I/O performance the chances are that you have experienced waits on writing to the Redo, Transaction Log or WAL depending on the database you are testing. A good example of how tuning is an iterative process.

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The Speed of Time

Brendan Gregg

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. As (C) looked like a kernel rebuild, I started with (D) and (E). ## 6. I also rewrote this in C and called gettimeofday(2) directly: $ cat gettimeofdaybench.c What on Earth is Ubuntu doing that results in 30% higher CPU time!?

Speed 40
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HammerDB MySQL and MariaDB Best Practice for Performance and Scalability

HammerDB

This post complements the previous best practice guides this time with the focus on MySQL and MariaDB and achieving top levels of performance with the HammerDB MySQL TPC-C test. SELECT DISTINCT c from sbtest where id between ? order by c. SELECT c from sbtest where id=? HammerDB difference from Sysbench. perf special.

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How To Scale a Single-Host PostgreSQL Database With Citus

Percona

Leveraging pgbench , which is a benchmarking utility that comes bundled with PostgreSQL, I will put the cluster through its paces by executing a series of DML operations. And now, execute the benchmark: -- execute the following on the coordinator node pgbench -c 20 -j 3 -T 60 -P 3 pgbench The results are not pretty.

Database 106
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A peculiar throughput limitation on Intel’s Xeon Phi x200 (Knights Landing)

John McCalpin

Each of the two vector units can issue one FMA instruction per cycle, assuming that there are enough independent accumulators to tolerate the 6-cycle dependent-operation latency. of the “adjusted peak performance”, there is no longer a significant upside to performance tuning. vfmadd213pd %zmm16, %zmm17, %zmm26.

Latency 40