# PostgreSQL_get_cache_hit_ratios

Calculate cache hit ratios for buffer and index performance analysis.

Agent View of the PolicyLayer registry record for `PostgreSQL_get_cache_hit_ratios`. HTML page: https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-get-cache-hit-ratios

## Facts

- Tool: `PostgreSQL_get_cache_hit_ratios`
- Server: Postgres (`mukul975/postgres-mcp-server`) — https://policylayer.com/tools/mukul975-postgres-mcp-server.md
- Homepage: https://github.com/mukul975/postgres-mcp-server
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "PostgreSQL_get_cache_hit_ratios",
    "arguments": {}
  }
}
```

## Why PostgreSQL_get_cache_hit_ratios is rated Low

This tool reads database performance statistics and computes derived metrics (cache hit ratios) for diagnostic purposes. It has no side effects, does not modify data, does not execute arbitrary commands, and does not delete or move resources. It fits the Read category as it retrieves and queries performance data for analysis only.

From the tool's own definition: "Tool name and description indicate a calculation/analysis operation: 'Calculate cache hit ratios for buffer and index performance analysis.' The verb 'calculate' and context of 'performance analysis' show this retrieves and analyzes existing performance…"

## Use case

AI agents call PostgreSQL_get_cache_hit_ratios to retrieve information from Postgres without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Postgres:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "PostgreSQL_get_cache_hit_ratios": {}
  }
}
```

## Other tools on Postgres (238)

- `PostgreSQL_drop_index` — Destructive — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-drop-index.md
- `PostgreSQL_drop_schema` — Destructive — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-drop-schema.md
- `PostgreSQL_drop_user` — Destructive — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-drop-user.md
- `PostgreSQL_analyze_database` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-analyze-database.md
- `PostgreSQL_execute_select_query` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-execute-select-query.md
- `PostgreSQL_execute_update_query` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-execute-update-query.md
- `PostgreSQL_kill_connection` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-kill-connection.md
- `PostgreSQL_refresh_materialized_view` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-refresh-materialized-view.md
- `PostgreSQL_vacuum_analyze_table` — Execute — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-vacuum-analyze-table.md
- `analyze_buffer_utilization` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-buffer-utilization.md
- `analyze_foreign_key_locks` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-foreign-key-locks.md
- `analyze_index_effectiveness` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-index-effectiveness.md
- `analyze_query_complexity` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-query-complexity.md
- `analyze_query_plans` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-query-plans.md
- `analyze_sequence_usage` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-sequence-usage.md
- `analyze_transaction_wraparound` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-transaction-wraparound.md
- `analyze_trigger_performance` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-trigger-performance.md
- `analyze_vacuum_efficiency` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/analyze-vacuum-efficiency.md
- `check_constraint_violations` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/check-constraint-violations.md
- `check_database_encoding_collation` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/check-database-encoding-collation.md
- `check_function_performance` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/check-function-performance.md
- `check_replication_lag_details` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/check-replication-lag-details.md
- `check_table_inheritance` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/check-table-inheritance.md
- `monitor_autovacuum_progress` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/monitor-autovacuum-progress.md
- `monitor_checkpoint_efficiency` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/monitor-checkpoint-efficiency.md
- `monitor_connection_patterns` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/monitor-connection-patterns.md
- `monitor_materialized_views` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/monitor-materialized-views.md
- `monitor_wal_generation_rate` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/monitor-wal-generation-rate.md
- `PostgreSQL_active_temp_file_users` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-active-temp-file-users.md
- `PostgreSQL_analyze_advanced_buffer_usage` — Read — https://policylayer.com/tools/mukul975-postgres-mcp-server/postgresql-analyze-advanced-buffer-usage.md
- …and 208 more: https://policylayer.com/tools/mukul975-postgres-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=mukul975-postgres-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/mukul975-postgres-mcp-server