dbstat(8)

💖 dbstat(8) 💖

System Manager's Manual 🎀

✨ NAME ✨

okay so dbstat is the tool that collects histograms of MySQL/PostgreSQL query latencies 📊 bestie, this one is lowkey iconic 💅

🦋 SYNOPSIS 🦋

dbstat [-v] [-p PID [PID ...]] [-m THRESHOLD] [-u] [-i INTERVAL]
{mysql,postgres}

🌸 DESCRIPTION 🌸

So this traces queries served by a MySQL or PostgreSQL server and builds a histogram of query latencies 🔥 The histogram gets printed when collection ends, or at whatever intervals you ask for.

It uses User Statically-Defined Tracing (USDT) probes, which MySQL and PostgreSQL added for DTrace support. Those probes might not be enabled on your installation though, so see REQUIREMENTS 🙈

Since this uses BPF, only the root user can use this tool. No root, no dbstat, periodt 💀

🎀 REQUIREMENTS 🎀

You need CONFIG_BPF, bcc, and either:

• A MySQL server with USDT probe support, which means configuring the build with -DENABLE_DTRACE=1
• A PostgreSQL server with USDT probe support, which means configuring the build with --enable-dtrace

💅 OPTIONS 💅

• -h — prints the usage message 🫶
• -p PID — traces this PID. If you don't give one, the tool tries to automatically find the MySQL or PostgreSQL processes running on the system ✨
• -m THRESHOLD — the minimum query latency (duration) to trace, in milliseconds. The default is all queries 🧚
• -u — shows query latencies in microseconds instead of the default milliseconds 🌈
• -i INTERVAL — prints summaries (histograms) at this interval, in seconds ⏰
• {mysql,postgres} — the database engine you want to trace 🍓

🧁 EXAMPLES 🧁

Display a histogram of MySQL query latencies:

# dbstat mysql

Display a histogram of PostgreSQL query latencies slower than 10ms in pid 408:

# dbstat postgres -p 408 -m 10

Display a histogram of PostgreSQL query latencies at 3-second intervals:

# dbstat postgres -i 3

🌙 OVERHEAD 🌙

Okay the vibe here is low-overhead ✨ It adds lightweight instrumentation to queries, and only sends output data from the kernel to user level if a query exceeds the threshold. If the server query rate is less than 1,000/sec, the overhead is expected to be negligible. If the query rate is higher, test it to gauge the overhead 📈

📦 SOURCE 📦

This is from bcc 🦋

https://github.com/iovisor/bcc

Also look in the bcc distribution for a companion _examples.txt file, which has example usage, output, and commentary for this tool 📚

💻 OS 💻

Linux only, bestie 🐧

🚧 STABILITY 🚧

Unstable - in development. Use with care, it's still cooking 🍳

👩‍💻 AUTHOR 👩‍💻

Sasha Goldshtein, the main character behind this one 👑

🔗 SEE ALSO 🔗

dbslower(8) is the one to check out next 💜

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Sourced from bcc, OS Linux, filed under USER COMMANDS and dated 2017-02-15, dbstat(8) is giving old-school reliable energy 🫶💖