cloudthinker-ai Memcached Management Skill
Monitor, analyze, and optimize Memcached instances safely.
MANDATORY: Discovery-First Pattern
Always run stats commands before inspecting specific slabs or items. Never assume slab classes or item counts.
Phase 1: Discovery
#!/bin/bash
MC_HOST="${MEMCACHED_HOST:-localhost}"
MC_PORT="${MEMCACHED_PORT:-11211}"
mc_cmd() {
echo "$1" | nc -q2 "$MC_HOST" "$MC_PORT" 2>/dev/null || \
echo "$1" | nc -w2 "$MC_HOST" "$MC_PORT" 2>/dev/null
}
echo "=== General Stats ==="
mc_cmd "stats" | grep -E 'version|uptime|curr_connections|total_connections|curr_items|total_items|bytes |limit_maxbytes|evictions|get_hits|get_misses|cmd_get|cmd_set'
echo ""
echo "=== Hit Ratio ==="
mc_cmd "stats" | awk -F' ' '
/get_hits/ { hits=$3 }
/get_misses/ { misses=$3 }
END {
total = hits + misses
if (total > 0) printf "Hit ratio: %.1f%% (%s hits, %s misses)\n", hits/total*100, hits, misses
else print "No gets recorded yet"
}'
echo ""
echo "=== Memory Usage ==="
mc_cmd "stats" | awk -F' ' '
/^STAT bytes / { used=$3 }
/limit_maxbytes/ { limit=$3 }
END {
if (limit > 0) printf "Memory: %dMB / %dMB (%.1f%%)\n", used/1048576, limit/1048576, used/limit*100
}'
echo ""
echo "=== Slab Overview ==="
mc_cmd "stats slabs" | grep -E 'chunk_size|used_chunks|total_chunks|mem_requested' | head -20
Phase 1 outputs: Version, connection count, item count, hit ratio, memory utilization, slab allocation.
Phase 2: Analysis
#!/bin/bash
MC_HOST="${MEMCACHED_HOST:-localhost}"
MC_PORT="${MEMCACHED_PORT:-11211}"
mc_cmd() {
echo "$1" | nc -q2 "$MC_HOST" "$MC_PORT" 2>/dev/null || \
echo "$1" | nc -w2 "$MC_HOST" "$MC_PORT" 2>/dev/null
}
echo "=== Slab Efficiency ==="
mc_cmd "stats slabs" | awk -F'[: ]' '
/used_chunks/ { slab=$2; used[$2]=$4 }
/total_chunks/ { total[$2]=$4 }
END {
for (s in used) {
if (total[s] > 0) printf "Slab %s: %s/%s chunks used (%.0f%%)\n", s, used[s], total[s], used[s]/total[s]*100
}
}' | sort -t: -k1 -n
echo ""
echo "=== Eviction Stats ==="
mc_cmd "stats items" | grep -E 'evicted|outofmemory|crawler' | head -15
echo ""
echo "=== Connection Analysis ==="
mc_cmd "stats" | grep -E 'curr_connections|listen_disabled|conn_yields|rejected_connections'
echo ""
echo "=== Growth Trends ==="
mc_cmd "stats" | grep -E 'total_items|evictions|reclaimed|expired_unfetched'
Output Format
MEMCACHED ANALYSIS
==================
Version: [version] | Uptime: [days]d
Memory: [used]/[limit] | Items: [count] | Hit Ratio: [pct]%
ISSUES FOUND:
- [issue with affected component]
RECOMMENDATIONS:
- [actionable recommendation]
Anti-Hallucination Rules
- NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
- NEVER fabricate metric names or dimensions — verify against the service documentation or
--helpoutput. - NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
- ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
- ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.
Counter-Rationalizations
| Shortcut | Counter | Why |
|---|---|---|
| "I'll skip discovery and check known resources" | Always run Phase 1 discovery first | Resource names change, new resources appear — assumed names cause errors |
| "The user only asked for a quick check" | Follow the full discovery → analysis flow | Quick checks miss critical issues; structured analysis catches silent failures |
| "Default configuration is probably fine" | Audit configuration explicitly | Defaults often leave logging, security, and optimization features disabled |
| "Metrics aren't needed for this" | Always check relevant metrics when available | API/CLI responses show current state; metrics reveal trends and intermittent issues |
| "I don't have access to that" | Try the command and report the actual error | Assumed permission failures prevent useful investigation; actual errors are informative |