dbslower-bpfcc8
Trace mysql/postgresql server queries slower than a threshold.
Usage
dbslower [-v]
[-p
PID
[PID ...]]
[-x
PATH]
[-m
THRESHOLD]
mysql,postgres
Overview
This traces queries served by a MySQL or PostgreSQL server, and prints those that exceed a latency (query time) threshold. By default a threshold of 1 ms is used.
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. Alternatively, MySQL queries can be traced without the USDT support using the -x option.
Since this uses BPF, only the root user can use this tool.
Requirements
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).
Options
-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.
-
-x PATH -
Path to MySQL binary. This option allow to MySQL queries even when USDT probes aren't enabled on the MySQL server.
-
-m THRESHOLD -
Minimum query latency (duration) to trace, in milliseconds. Default is 1 ms.
- {mysql,postgres}
-
The database engine to trace.
Examples
Trace MySQL server queries slower than 1 ms:
|
# dbslower mysql |
|---|---|
Trace slower than 10 ms for PostgreSQL in process 408:
|
# dbslower postgres -p 408 -m 10 |
Fields
TIME(s)
|
Time of query start, in seconds. |
|---|---|
PID
|
Process ID of the traced server. |
MS
|
Milliseconds for the query, from start to end. |
QUERY
|
Query string, truncated to 256 characters. |
Overhead
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.
Source
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.
OS
Linux
Stability
Unstable - in development.
Releases
4 releases since Debian 10 (Buster); the text changed 1 time.