RAC Interconnect

Inspect the network interfaces Oracle is using for cluster communication on each RAC instance.

SELECT
    inst_id,
    name,
    ip_address,
    is_public,
    source,
    transport
FROM gv$cluster_interconnects
ORDER BY
    inst_id,
    name;

Compare the interconnect interfaces Oracle is aware of and where their configuration information came from.

SELECT
    inst_id,
    name,
    ip_address,
    is_public,
    source
FROM gv$configured_interconnects
ORDER BY
    inst_id,
    name;

Inspect GES message statistics that provide context for inter-instance messaging activity.

SELECT
    inst_id,
    name,
    value
FROM gv$ges_statistics
WHERE name IN (
    'messages sent directly',
    'messages flow controlled',
    'messages sent indirectly',
    'messages received',
    'flow control messages sent',
    'flow control messages received'
)
ORDER BY
    inst_id,
    name;

Inspect Global Cache Service statistics for remote consistent-read and current block requests handled by LMS processes.

SELECT
    inst_id,
    cr_requests,
    current_requests,
    data_requests,
    undo_requests,
    tx_requests,
    other_requests
FROM gv$cr_block_server
ORDER BY inst_id;

Review LMS pin and flush timing buckets to understand current-block processing activity by instance.

SELECT
    inst_id,
    pin0,
    pin1,
    pin10,
    pin100,
    pin1000,
    pin10000,
    flush0,
    flush1,
    flush10,
    flush100,
    flush1000,
    flush10000
FROM gv$current_block_server
ORDER BY inst_id;

Compare RAC global cache wait events across instances and identify where time is being spent waiting for Cache Fusion activity.

SELECT
    inst_id,
    event,
    total_waits,
    ROUND(time_waited / 100, 2) AS wait_seconds
FROM gv$system_event
WHERE event LIKE 'gc %'
ORDER BY
    time_waited DESC
FETCH FIRST 20 ROWS ONLY;