Connection Pool Performance Analysis

Analyze PHP code for connection pool issues and database connection management problems.

When to Use

Reviewing database-heavy PHP applications
Investigating connection exhaustion or memory leaks
Auditing long-running workers (queue consumers, daemons)
Checking Doctrine EntityManager lifecycle issues
Reviewing HTTP client usage patterns

Analysis Approach

Scan for connection creation patterns (PDO, Redis, Guzzle)
Check loop bodies for repeated connection instantiation
Verify try/finally cleanup on pool acquire/release
Check timeout configuration on all connection types
Review persistent connection usage and state reset
Audit worker processes for connection refresh logic

Detection Rules

ID	Pattern	What to Look For
CP-01	Connection leak	`new PDO` without cleanup in exception/early-return paths
CP-02	Connection in loop	`new PDO`/`new Redis`/`new Client` inside foreach/while
CP-03	Missing timeout	PDO without `ATTR_TIMEOUT`, Redis without connect timeout
CP-04	Persistent misuse	`ATTR_PERSISTENT => true` without shutdown cleanup
CP-05	Pool exhaustion	Multiple connections opened without reuse
CP-06	Missing finally	`$pool->release()` not in finally block
CP-07	State not reset	Connection returned to pool with modified session state
CP-08	Doctrine issues	EntityManager not cleared, long-held transactions
CP-09	Worker stale conn	Long-running worker without connection refresh
CP-10	HTTP no pooling	`file_get_contents` in loop, no keep-alive headers

Grep Patterns

# New connection in loops
Grep: "foreach.*\{[^}]*new PDO|while.*\{[^}]*new PDO" --glob "**/*.php" --multiline

# Missing connection close
Grep: "new Redis\(\)" --glob "**/*.php"

# Persistent connections
Grep: "ATTR_PERSISTENT" --glob "**/*.php"

# Connection without timeout
Grep: "new PDO\s*\([^)]+\)\s*;" --glob "**/*.php"

# Static connection storage
Grep: "static.*PDO|static.*connection" --glob "**/*.php"

Severity Classification

Pattern	Severity
Connection in loop	Critical
Connection leak (no finally)	Critical
No connection timeout	Major
Pool exhaustion risk	Major
Missing connection health check	Major
Persistent connection misuse	Minor
Static connection storage	Minor

Output Format

### Connection Pool: [Description]

**Severity:** Critical/Major/Minor
**Location:** `file.php:line`
**Impact:** [Database overload, connection exhaustion, memory leak]

**Issue:**
[Description of the connection management problem]

**Code:**
[Problematic code snippet]

**Fix:**
[Proper connection management code]

**Expected Improvement:**
- Connection count: 100 -> 10 (pooled)
- Memory usage: -50% (connections reused)
- DB load: -80% (connection overhead eliminated)

References

references/patterns.md — detailed detection patterns with code examples, secure pool implementations, health check and worker refresh patterns

Analysis Approach

Scan for connection creation patterns (PDO, Redis, Guzzle)

Check loop bodies for repeated connection instantiation

Verify try/finally cleanup on pool acquire/release

Check timeout configuration on all connection types

Review persistent connection usage and state reset

Audit worker processes for connection refresh logic

Detection Rules

Pattern

What to Look For

CP-01

Connection leak

new PDO without cleanup in exception/early-return paths

CP-02

Connection in loop

new PDO/new Redis/new Client inside foreach/while

CP-03

Missing timeout

PDO without ATTR_TIMEOUT, Redis without connect timeout

CP-04

Persistent misuse

ATTR_PERSISTENT => true without shutdown cleanup

CP-05

Pool exhaustion

Multiple connections opened without reuse

CP-06

Missing finally

$pool->release() not in finally block

CP-07

State not reset

Connection returned to pool with modified session state

CP-08

Doctrine issues

EntityManager not cleared, long-held transactions

CP-09

Worker stale conn

Long-running worker without connection refresh

CP-10

HTTP no pooling

file_get_contents in loop, no keep-alive headers

Grep Patterns

# New connection in loops Grep: "foreach.*\{[^}]*new PDO|while.*\{[^}]*new PDO" --glob "**/*.php" --multiline # Missing connection close Grep: "new Redis" --glob "**/*.php" # Persistent connections Grep: "ATTR_PERSISTENT" --glob "**/*.php" # Connection without timeout Grep: "new PDO\s*$[^)]+$\s*;" --glob "**/*.php" # Static connection storage Grep: "static.*PDO|static.*connection" --glob "**/*.php"

Pattern

Severity

Connection in loop

Critical

Connection leak (no finally)

Critical

No connection timeout

Major

Pool exhaustion risk

Major

Missing connection health check

Major

Persistent connection misuse

Minor

Static connection storage

Minor

Output Format

### Connection Pool: [Description] **Severity:** Critical/Major/Minor **Location:** `file.php:line` **Impact:** [Database overload, connection exhaustion, memory leak] **Issue:** [Description of the connection management problem] **Code:** [Problematic code snippet] **Fix:** [Proper connection management code] **Expected Improvement:** - Connection count: 100 -> 10 (pooled) - Memory usage: -50% (connections reused) - DB load: -80% (connection overhead eliminated)

check-connection-pool

Connection Pool Performance Analysis

When to Use

Analysis Approach

Detection Rules

Grep Patterns

Severity Classification

Output Format

References

check-connection-pool

Connection Pool Performance Analysis

When to Use

Analysis Approach

Detection Rules

Grep Patterns

Severity Classification

Output Format

References