JDBC QueryLog

jdbc-querylog is a JDBC driver, which provides hook points to trace all queries.

SYNOPSIS

Use 'jdbc:querylog:' prefix for JDBC connection uri.

    QueryLogDriver.setExplain(true);
    try (Connection conn = DriverManager.getConnection("jdbc:querylog:h2:mem:test")) {
        try (PreparedStatement stmt = conn.prepareStatement("SELECT * FROM user WHERE id=?")) {
            stmt.setInt(1, 1);
            try (ResultSet resultSet = stmt.executeQuery()) {
            }
        }
        try (PreparedStatement stmt = conn.prepareStatement("SELECT * FROM user")) {
            try (ResultSet resultSet = stmt.executeQuery()) {
            }
        }
    }

Then, you got automatic EXPLAIN.

Query: SELECT * FROM user WHERE id=1
┌────────────────────────────────────────┐
│ PLAN                                   │
├────────────────────────────────────────┤
│ SELECT                                 │
│ USER.ID,                               │
│ USER.NAME                              │
│ FROM PUBLIC.USER                       │
│ /* PUBLIC.PRIMARY_KEY_2: ID = 1 */     │
│ WHERE ID = 1                           │
└────────────────────────────────────────┘

Query: SELECT * FROM user
┌─────────────────────────────────┐
│ PLAN                            │
├─────────────────────────────────┤
│ SELECT                          │
│ USER.ID,                        │
│ USER.NAME                       │
│ FROM PUBLIC.USER                │
│ /* PUBLIC.USER.tableScan */     │
└─────────────────────────────────┘

Use cases

• Record all statements executed by JDBC driver
• Detect heavy queries in development environment.
  • Send EXPLAIN statement
• Logging queries and parameters.
• Detect webapp controller, that sends too much SQL queries.

Usage

If your JDBC uri is this:

jdbc:mysql://localhost/test

Then, you need to rewrite the uri as following:

jdbc:querylog:mysql://localhost/test

That's all.

Options

QueryLogDriver.setExplain(true) : Default false

Enable automatic EXPLAIN statement generation.

(Note, this feature only supports mysql. patches welcome)

QueryLogDriver.setCompact(true) : Default true

Compact SQL query before query logging.

QueryLogDriver.setQueryHandler(Connection connection, String query)

    QueryLogDriver.setQueryHandler((connection, query) -> {
        System.err.println("Query: " + query);
    });

Added query handler. If you set this handler, querylog pass the query to the callback handler.

QueryLogDriver.setExplainHandler(ExplainHandler printExplain)

    QueryLogDriver.setExplainHandler((connection, query, header, rows) -> {
        System.err.println("Query: " + query);
        System.err.println("Header: " + Arrays.toString(header));
        System.err.println("Rows: " + rows.stream()
                .map(it -> Arrays.stream(it).collect(Collectors.joining(",")))
                .collect(Collectors.joining("\n")));
    });

Set explain handler. If you call QueryLogDriver.setExplain(true), querylog sends EXPLAIN statement to DB server, and pass the results to the callback listener.

jdbc-tracer

jdbc-querylog is based on jdbc-tracer. jdbc-tracer provides following two listener interfaces.

PreparedStatementListener

You can get following values for each executed queries:

• connection
• elapsed time
• SQL statement
• binded variables

ResultSetListener

You can get following values for each got rows:

• isFirstRow
  • You may print column information on first row.
• resultSet
  • you can get resultset information!
    • (MUST NOT call next() from the listener. it cause infinite loop)

Install

You can install this library from maven central.

SEE ALSO

This is a port of Perl5's DBIx::QueryLog.

http://search.cpan.org/perldoc?DBIx%3A%3AQueryLog

License

The MIT License (MIT)
Copyright © 2016 Tokuhiro Matsuno, http://64p.org/ <tokuhirom@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
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copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

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