# PostgreSQL_buffer_cache_hit_ratio

Analyze buffer cache hit ratios for all databases and tables.

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

## Facts

- Tool: `PostgreSQL_buffer_cache_hit_ratio`
- 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_buffer_cache_hit_ratio",
    "arguments": {}
  }
}
```

## Why PostgreSQL_buffer_cache_hit_ratio is rated Low

This tool retrieves and analyzes performance metrics (buffer cache hit ratios) from PostgreSQL databases. It performs read-only diagnostic operations to assess cache performance without creating, modifying, deleting, or executing external operations. The blast radius if misused by an AI agent is minimal—it only accesses existing performance data.

From the tool's own definition: "Tool name contains 'Analyze' and description states 'Analyze buffer cache hit ratios' - both indicate data retrieval and analysis only. No modification, deletion, execution of code, or financial operations are implied."

## Use case

AI agents call PostgreSQL_buffer_cache_hit_ratio 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_buffer_cache_hit_ratio": {}
  }
}
```

## 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`

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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