dbstat - Collect histograms of MySQL/PostgreSQL query latencies. . B dbstat [-v] [-p PID [PID ...]] [-m THRESHOLD] [-u] [-i INTERVAL] {mysql,postgres} This traces queries served by a MySQL or PostgreSQL server, and collects a histogram of query latencies. The histogram is printed at the end of collection, or at specified intervals. This uses User Statically-Defined Tracing (USDT) probes, a feature added to MySQL and PostgreSQL for DTrace support, but which may not be enabled on a given installation. See requirements. Since this uses BPF, only the root user can use this tool. CONFIG_BPF, bcc, and MySQL server with USDT probe support (when configuring the build: -DENABLE_DTRACE=1) or PostgreSQL server with USDT probe support (when configuring the build: --enable-dtrace). -h Print usage message.

-p PID Trace this PID. If no PID is specified, the tool will attempt to automatically detect the MySQL or PostgreSQL processes running on the system.

-m THRESHOLD Minimum query latency (duration) to trace, in milliseconds. Default is all queries.

-u Display query latencies in microseconds (default: milliseconds).

-i INTERVAL Print summaries (histograms) at this interval, specified in seconds.

{mysql,postgres} The database engine to trace.

Display histogram of MySQL query latencies: # dbstat mysql

Display histogram of PostgreSQL query latencies slower than 10ms in pid 408: # dbstat postgres -p 408 -m 10

Display histogram of PostgreSQL query latencies at 3-second intervals: # dbstat postgres -i 3

This adds low-overhead instrumentation to queries, and only emits output data from kernel to user-level if they 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 to gauge overhead. This is from bcc. https://github.com/iovisor/bcc

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

Linux Unstable - in development. Sasha Goldshtein dbslower(8)