feat(consumoor): bump default ClickHouse maxConns from 8 to 32

docs/consumoor-runbook.md

@@ -265,7 +265,7 @@ Common causes of startup failure:
 
 ### Vertical Scaling
 
-- Increase `maxConns` to allow more concurrent ClickHouse writes (default: 8)
+- Increase `maxConns` to allow more concurrent ClickHouse writes (default: 32)
 - Increase `batchSize` to write more rows per INSERT (default: 200000)
 - Increase `bufferSize` to absorb more backpressure spikes (default: 200000), at the cost of higher memory usage
 - Increase pod CPU/memory to handle more concurrent table writers
@@ -280,7 +280,7 @@ Common causes of startup failure:
 | `flushInterval` | `clickhouse.defaults.flushInterval` | 1s | Decrease for lower latency; increase if batches are too small |
 | `bufferSize` | `clickhouse.defaults.bufferSize` | 200000 | Increase to absorb ClickHouse hiccups without backpressure; decrease to limit memory |
 | `commitInterval` | `kafka.commitInterval` | 5s | Decrease to reduce duplicate replay window on crash; increase to reduce Kafka commit overhead |
-| `maxConns` | `clickhouse.chgo.maxConns` | 8 | Increase when `chgo_pool_empty_acquire_total` is high |
+| `maxConns` | `clickhouse.chgo.maxConns` | 32 | Increase when `chgo_pool_empty_acquire_total` is high |
 | `queryTimeout` | `clickhouse.chgo.queryTimeout` | 30s | Increase if large batches legitimately take longer to insert |
 | `maxRetries` | `clickhouse.chgo.maxRetries` | 3 | Increase if transient ClickHouse errors are frequent but recover quickly |
 | `deliveryMode` | `kafka.deliveryMode` | batch | Use `message` for safer per-message delivery; use `batch` for higher throughput |

example_consumoor.yaml

@@ -49,7 +49,7 @@ clickhouse:
   #   maxRetries: 3
   #   retryBaseDelay: 100ms
   #   retryMaxDelay: 2s
-  #   maxConns: 8
+  #   maxConns: 32
   #   minConns: 1
   #   connMaxLifetime: 1h
   #   connMaxIdleTime: 10m

pkg/consumoor/clickhouse/config.go

@@ -98,7 +98,7 @@ type ChGoConfig struct {
 	RetryMaxDelay time.Duration `yaml:"retryMaxDelay" default:"2s"`
 
 	// MaxConns is the maximum number of pooled ClickHouse connections.
-	MaxConns int32 `yaml:"maxConns" default:"8"`
+	MaxConns int32 `yaml:"maxConns" default:"32"`
 	// MinConns is the minimum number of pooled ClickHouse connections.
 	MinConns int32 `yaml:"minConns" default:"1"`
 	// ConnMaxLifetime is the maximum lifetime for pooled connections.

pkg/consumoor/clickhouse/config_test.go

@@ -31,7 +31,7 @@ func validChGoConfig() ChGoConfig {
 		MaxRetries:          3,
 		RetryBaseDelay:      100 * time.Millisecond,
 		RetryMaxDelay:       2 * time.Second,
-		MaxConns:            8,
+		MaxConns:            32,
 		MinConns:            1,
 		ConnMaxLifetime:     1 * time.Hour,
 		ConnMaxIdleTime:     10 * time.Minute,

pkg/consumoor/clickhouse/writer_test.go

@@ -85,7 +85,7 @@ func TestChGoConfigValidateAcceptsValidConfig(t *testing.T) {
 		ReadTimeout:       30 * time.Second,
 		RetryBaseDelay:    100 * time.Millisecond,
 		RetryMaxDelay:     2 * time.Second,
-		MaxConns:          8,
+		MaxConns:          32,
 		MinConns:          0,
 		ConnMaxLifetime:   time.Hour,
 		ConnMaxIdleTime:   10 * time.Minute,
@@ -421,7 +421,7 @@ func TestBufferWarningThresholdValidation(t *testing.T) {
 		ReadTimeout:       30 * time.Second,
 		RetryBaseDelay:    100 * time.Millisecond,
 		RetryMaxDelay:     2 * time.Second,
-		MaxConns:          8,
+		MaxConns:          32,
 		MinConns:          1,
 		ConnMaxLifetime:   time.Hour,
 		ConnMaxIdleTime:   10 * time.Minute,

pkg/consumoor/config_test.go

@@ -20,7 +20,7 @@ func validChGoConfig() clickhouse.ChGoConfig {
 		MaxRetries:          3,
 		RetryBaseDelay:      100 * time.Millisecond,
 		RetryMaxDelay:       2 * time.Second,
-		MaxConns:            8,
+		MaxConns:            32,
 		MinConns:            1,
 		ConnMaxLifetime:     time.Hour,
 		ConnMaxIdleTime:     10 * time.Minute,