1 unstable release
0.3.0 | Oct 15, 2024 |
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#1728 in Database interfaces
6,680 downloads per month
Used in qorb
16KB
168 lines
diesel-dtrace
Add DTrace probes to Diesel connections.
Overview
The diesel-dtrace
crate provides a diesel Connection
that includes DTrace probe points.
Probes are fired when a connection to the database is established and for each query.
In order to register probes, your program must invoke usdt::register_probes()
before the probe points are executed.
Probes
diesel-db*:::connection-establish-start(id: uint64_t, conn_id: Uuid, url: &str);
diesel-db*:::connection-establish-done(id: uint64_t, conn_id: Uuid, success: u8);
diesel-db*:::query-start(id: uint64_t, conn_id: Uuid, query: &str);
diesel-db*:::query-done(id: uint64_t, conn_id: Uuid);
diesel-db*:::transaction-start(id: uint64_t, conn_id: Uuid);
diesel-db*:::transaction-done(id: uint64_t, conn_id: Uuid);
Example
The example at examples/conn.rs
attempts to connect to a PostgreSQL database at the URL
provided (or localhost:5432), and run a few simple queries. The probes fired by the example can
be seen with:
# dtrace -Zqn 'diesel*::: { printf("%s (%d)\n", probename, arg0) }'
connection_establish_start (4294967297)
connection_establish_end (4294967297)
query_start (4294967298)
query_end (4294967298)
query_start (4294967299)
query_end (4294967299)
All probes emit a unique ID as their first argument, which allows correlating the start/end probes. This is crucial for timing the latency of queries, or predicating other DTrace actions on a connection being established or query executing (e.g., tracing all system calls while a query is running).
Notes
This crate relies on the usdt
crate. On macOS systems, a nightly
compiler is required prior to Rust 1.67. On other systems a nightly compiler is
required prior to Rust 1.59.
Dependencies
~7–13MB
~168K SLoC