背景

我试图通过在stackdriver-agents collectd配置目录中向我的PostgreSQL配置（来自Stackdriver PostgreSQL Plugin的原始配置）添加自定义 <Query> 语句来导出PostgreSQL复制延迟 .

/opt/stackdriver/collectd/etc/postgresql.conf ：

# This is the monitoring configuration for PostgreSQL.
# Make sure the statistics collector is enabled in your PostgreSQL configuration.
# NOTE: This configuration needs to be hand-edited in order to work.
# Look for DATABASE_NAME, STATS_USER, STATS_PASS, POSTGRESQL_HOST and POSTGRESQL_PORT to adjust your configuration file.
LoadPlugin postgresql
<Plugin "postgresql">

    <Query replication_lag_seconds>
        Statement "SELECT (CASE WHEN pg_last_xlog_receive_location() = pg_last_xlog_replay_location() THEN 0 ELSE EXTRACT (EPOCH FROM now() - pg_last_xact_replay_timestamp()) END) AS log_delay"
        <Result>
            Type "gauge"
            ValuesFrom "log_delay"
        </Result>
    </Query>

    # Each database needs a separate Database section.
    # Replace DATABASE_NAME in the Database section with the name of the database.
    <Database "THE_DATABASE">
        # Host and port are only used for TCP/IP connections.
        # Leaving them out indicates you wish to connect via domain sockets.
        # When using non-standard PostgreSQL configurations, replace the below with
        Host "localhost"
        Port "5432"
        User "THE_USER"
        Password "hunter2"
        Query backends
        Query transactions
        Query queries
        Query table_states
        Query disk_io
        Query disk_usage
        Query replication_lag_seconds  # My custom query
    </Database>
</Plugin>

stackdriver-agent日志确认插件已加载，插件能够连接到PostgreSQL服务器 .

collectd[30418]: plugin_load: plugin "postgresql" successfully loaded.
collectd[13849]: Successfully connected to database THE_DATABASE (user THE_USER) at server localhost:5432 (server version: 9.4.12, protocol version: 3, pid: 13862)

到目前为止，在查看“实例（GCE）”资源的指标时，我希望看到我的“log_delay”指标显示在Stackdriver监控中 . 我可以看到其他PostgreSQL指标已经完成，更具体地说：

我似乎也找不到从Stackdriver PostgreSQL Plugin Documentation引用的default PostgreSQL collectd configuration继承的任何其他默认 Query [...] 指标：

# [...]
LoadPlugin postgresql
<Plugin "postgresql">
    # [...]
    <Database "DATABASE_NAME">
        # [...]
        User "STATS_USER"
        Password "STATS_PASS"
        Query backends
        Query transactions
        Query queries
        Query table_states
        Query disk_io
        Query disk_usage
    </Database>
</Plugin>

问题

• 如何将我的collecd自定义replication_lag_seconds指标显示在Stackdriver Monitoring中？

• 我是否需要配置Custom Metrics以便在Stackdriver Monitoring中显示指标？