Querying Data Collector Tables

Data Collector tables (prefixed by dc_) are in the V_INTERNAL schema. If you use Data Collector tables in scripts or monitoring tools, be aware that any Vertica upgrade is liable to remove or change them without notice.

You can obtain component-specific data from Data Collector tables. The Data Collector compiles the component data from its log files in a table format that you can query with standard SQL queries.  You can identify Data Collector table names for specific components through system table Data Collector. For example:

=> SELECT distinct component, table_name FROM data_collector where component ILIKE 'lock%';
  component   |    table_name
 LockRequests | dc_lock_requests
 LockReleases | dc_lock_releases
 LockAttempts | dc_lock_attempts
(3 rows)

You can then query the desired Data Collector tables—for example, check for lock delays in dc_lock_attempts:

=> SELECT * from dc_lock_attempts WHERE description != 'Granted immediately';
-[ RECORD 1 ]------+------------------------------
time               | 2020-08-17 00:14:07.187607-04
node_name          | v_vmart_node0001
session_id         | v_vmart_node0001-319647:0x1d
user_id            | 45035996273704962
user_name          | dbadmin
transaction_id     | 45035996273819050
object             | 0
object_name        | Global Catalog
mode               | X
promoted_mode      | X
scope              | TRANSACTION
start_time         | 2020-08-17 00:14:07.184663-04
timeout_in_seconds | 300
result             | granted
description        | Granted after waiting