#!/usr/bin/python
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#
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# mysqld_query Trace MySQL server queries. Example of USDT tracing.
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# For Linux, uses BCC, BPF. Embedded C.
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#
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# USAGE: mysqld_query PID
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#
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# This uses USDT probes, and needs a MySQL server with -DENABLE_DTRACE=1.
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#
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# Copyright 2016 Netflix, Inc.
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# Licensed under the Apache License, Version 2.0 (the "License")
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from __future__ import print_function
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from bcc import BPF, USDT
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import sys
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if len(sys.argv) < 2:
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print("USAGE: mysqld_latency PID")
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exit()
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pid = sys.argv[1]
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debug = 0
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# load BPF program
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bpf_text = """
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#include <uapi/linux/ptrace.h>
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int do_trace(struct pt_regs *ctx) {
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uint64_t addr;
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char query[128];
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/*
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* Read the first argument from the query-start probe, which is the query.
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* The format of this probe is:
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* query-start(query, connectionid, database, user, host)
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* see: https://dev.mysql.com/doc/refman/5.7/en/dba-dtrace-ref-query.html
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*/
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bpf_usdt_readarg(1, ctx, &addr);
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bpf_trace_printk("%s\\n", addr);
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return 0;
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};
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"""
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# enable USDT probe from given PID
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u = USDT(pid=int(pid))
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u.enable_probe(probe="query__start", fn_name="do_trace")
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if debug:
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print(u.get_text())
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print(bpf_text)
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# initialize BPF
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b = BPF(text=bpf_text, usdt_contexts=[u])
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# header
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print("%-18s %-16s %-6s %s" % ("TIME(s)", "COMM", "PID", "QUERY"))
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# format output
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while 1:
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try:
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(task, pid, cpu, flags, ts, msg) = b.trace_fields()
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except ValueError:
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print("value error")
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continue
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print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
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