ViduraRedshift Tools
Health Monitoring Tools
The health monitoring tools give Vidura visibility into the operational state of the Redshift cluster — table freshness, optimizer alerts, node hardware, and application registration. These 5 tools form the health monitoring subset of the 19 Redshift tools.
Tool Reference
| Tool Name | Data Source | Description |
|---|---|---|
| freshness_stats() | svv_table_info + stl_analyze | Returns the last ANALYZE timestamp per table. Tables not analyzed in more than 7 days are flagged with a stale_stats indicator. Use when asked about table statistics freshness or optimizer plan quality. |
| table_alerts() | stl_alert_event_log | Returns alert events from the past 7 days grouped by table. The alert type bitmask is decoded into human-readable names: Sortkey (1), Deletes (2), NL (4), Dist (8), Broadcast (16), Stats (32). |
| alert_logs() | quper.alert_logs | Returns the 5 most recent entries from the Quper application alert log table. Use when asked about recent platform alerts or system events. |
| node_details() | stv_slices + stv_node_storage_capacity | Returns hardware specs for each cluster node including node ID, slice count, total capacity, and used capacity. Node type is inferred by matching the reported capacity against the known node type capacity table. |
| application_names() | quper.applications | Returns all registered application names in the Quper metadata table. Used to populate filter dropdowns for query analysis tools that accept an application_name parameter. |
Node Type Detection Table
The node_details() tool infers the node type by matching the reported storage capacity against known thresholds. The complete lookup table used by the tool:
| Node Type | Capacity (MB) | Storage Type | Partitions |
|---|---|---|---|
| dc1.large | 190,633 | SSD | 2 |
| dc2.large | 190,633 | NVMe SSD | 2 |
| dc2.8xlarge | 760,956 | NVMe SSD | 16 |
| ra3.xlplus | 952,455 | Managed Storage (S3) | 4 |
| ra3.4xlarge | 3,339,176 | Managed Storage (S3) | 4 (1 per node) |
| ra3.16xlarge | 3,339,176 | Managed Storage (S3) | 16 (4 per node) |
Alert Bitmask Decoding
The table_alerts() tool decodes the event_type bitmask from stl_alert_event_log using bitwise AND:
| Bit Value | Alert Name | Detected When |
|---|---|---|
| 1 | Sortkey | event_type & 1 != 0 |
| 2 | Deletes | event_type & 2 != 0 |
| 4 | NL (Nested Loop) | event_type & 4 != 0 |
| 8 | Dist | event_type & 8 != 0 |
| 16 | Broadcast | event_type & 16 != 0 |
| 32 | Stats | event_type & 32 != 0 |
Bitmask Combinations
A single query can trigger multiple alert types simultaneously. For example, an event_type of 40 means both Dist (8) and Stats (32) were detected in the same query execution. The tool decodes all active bits and returns all matching alert names.