dbslower(8) System Manager's Manual dbslower(8)

# [NAME](#NAME)

dbslower - Trace MySQL/PostgreSQL server queries slower than a threshold.

# [SYNOPSIS](#SYNOPSIS)

**dbslower \[-v] \[-p PID \[PID ...]] \[-x PATH] \[-m THRESHOLD] {mysql,postgres}**

# [DESCRIPTION](#DESCRIPTION)

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](#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](#OPTIONS)

-h Print usage message.

[-p PID](#p)

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](#x)

Path to MySQL binary. This option allow to MySQL queries even when USDT probes aren't enabled on the MySQL server.

[-m THRESHOLD](#m)

Minimum query latency (duration) to trace, in milliseconds. Default is 1 ms.

{mysql,postgres}

The database engine to trace.

# [EXAMPLES](#EXAMPLES)

[Trace MySQL server queries slower than 1 ms:](#Trace)

\# **dbslower mysql**

[Trace slower than 10 ms for PostgreSQL in process 408:](#Trace~2)

\# **dbslower postgres -p 408 -m 10**

# [FIELDS](#FIELDS)

[TIME(s)](#TIME%28s%29)

Time of query start, in seconds.

[PID](#PID)

Process ID of the traced server.

[MS](#MS)

Milliseconds for the query, from start to end.

[QUERY](#QUERY)

Query string, truncated to 256 characters.

# [OVERHEAD](#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](#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](#OS)

Linux

# [STABILITY](#STABILITY)

Unstable - in development.

# [AUTHOR](#AUTHOR)

Sasha Goldshtein, Brendan Gregg

# [SEE ALSO](#SEE_ALSO)

[biosnoop(8)](/man/enterprise-packages/bcc/biosnoop.8), [mysqld\_qslower(8)](/man/enterprise-packages/bcc/mysqld_qslower.8), [dbstat(8)](/man/enterprise-packages/bcc/dbstat.8)

2017-02-15 USER COMMANDS

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Document: dbslower(8) from bcc 0.37.0-r2 (Chainguard OS)
Source: https://github.com/iovisor/bcc