tablet: remove max-waiters setting

config/tablet/default.yaml

@@ -57,21 +57,18 @@ oltpReadPool:
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   maxLifetimeSeconds: 0    # queryserver-config-pool-conn-max-lifetime
   prefillParallelism: 0    # queryserver-config-pool-prefill-parallelism
-  maxWaiters: 50000        # queryserver-config-query-pool-waiter-cap
 
 olapReadPool:
   size: 200                # queryserver-config-stream-pool-size
   timeoutSeconds: 0        # queryserver-config-query-pool-timeout
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   prefillParallelism: 0    # queryserver-config-stream-pool-prefill-parallelism
-  maxWaiters: 0
 
 txPool:
   size: 20                 # queryserver-config-transaction-cap
   timeoutSeconds: 1        # queryserver-config-txpool-timeout
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   prefillParallelism: 0    # queryserver-config-transaction-prefill-parallelism
-  maxWaiters: 50000        # queryserver-config-txpool-waiter-cap
 
 oltp:
   queryTimeoutSeconds: 30 # queryserver-config-query-timeout

doc/design-docs/TabletServerParamsAsYAML.md

@@ -95,21 +95,18 @@ oltpReadPool:
   timeoutSeconds: 0        # queryserver-config-query-pool-timeout
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   prefillParallelism: 0    # queryserver-config-pool-prefill-parallelism
-  maxWaiters: 50000        # queryserver-config-query-pool-waiter-cap
 
 olapReadPool:
   size: 200                # queryserver-config-stream-pool-size
   timeoutSeconds: 0        # queryserver-config-query-pool-timeout
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   prefillParallelism: 0    # queryserver-config-stream-pool-prefill-parallelism
-  maxWaiters: 0
 
 txPool:
   size: 20                 # queryserver-config-transaction-cap
   timeoutSeconds: 1        # queryserver-config-txpool-timeout
   idleTimeoutSeconds: 1800 # queryserver-config-idle-timeout
   prefillParallelism: 0    # queryserver-config-transaction-prefill-parallelism
-  maxWaiters: 50000        # queryserver-config-txpool-waiter-cap
 
 oltp:
   queryTimeoutSeconds: 30 # queryserver-config-query-timeout

go/flags/endtoend/vtcombo.txt

@@ -283,21 +283,18 @@ Flags:
       --queryserver-config-pool-size int                                 query server read pool size, connection pool is used by regular queries (non streaming, not in a transaction) (default 16)
       --queryserver-config-query-cache-memory int                        query server query cache size in bytes, maximum amount of memory to be used for caching. vttablet analyzes every incoming query and generate a query plan, these plans are being cached in a lru cache. This config controls the capacity of the lru cache. (default 33554432)
       --queryserver-config-query-pool-timeout duration                   query server query pool timeout, it is how long vttablet waits for a connection from the query pool. If set to 0 (default) then the overall query timeout is used instead.
-      --queryserver-config-query-pool-waiter-cap int                     query server query pool waiter limit, this is the maximum number of queries that can be queued waiting to get a connection (default 5000)
       --queryserver-config-query-timeout duration                        query server query timeout, this is the query timeout in vttablet side. If a query takes more than this timeout, it will be killed. (default 30s)
       --queryserver-config-schema-change-signal                          query server schema signal, will signal connected vtgates that schema has changed whenever this is detected. VTGates will need to have -schema_change_signal enabled for this to work (default true)
       --queryserver-config-schema-reload-time duration                   query server schema reload time, how often vttablet reloads schemas from underlying MySQL instance. vttablet keeps table schemas in its own memory and periodically refreshes it from MySQL. This config controls the reload time. (default 30m0s)
       --queryserver-config-stream-buffer-size int                        query server stream buffer size, the maximum number of bytes sent from vttablet for each stream call. It's recommended to keep this value in sync with vtgate's stream_buffer_size. (default 32768)
       --queryserver-config-stream-pool-size int                          query server stream connection pool size, stream pool is used by stream queries: queries that return results to client in a streaming fashion (default 200)
       --queryserver-config-stream-pool-timeout duration                  query server stream pool timeout, it is how long vttablet waits for a connection from the stream pool. If set to 0 (default) then there is no timeout.
-      --queryserver-config-stream-pool-waiter-cap int                    query server stream pool waiter limit, this is the maximum number of streaming queries that can be queued waiting to get a connection
       --queryserver-config-strict-table-acl                              only allow queries that pass table acl checks
       --queryserver-config-terse-errors                                  prevent bind vars from escaping in client error messages
       --queryserver-config-transaction-cap int                           query server transaction cap is the maximum number of transactions allowed to happen at any given point of a time for a single vttablet. E.g. by setting transaction cap to 100, there are at most 100 transactions will be processed by a vttablet and the 101th transaction will be blocked (and fail if it cannot get connection within specified timeout) (default 20)
       --queryserver-config-transaction-timeout duration                  query server transaction timeout, a transaction will be killed if it takes longer than this value (default 30s)
       --queryserver-config-truncate-error-len int                        truncate errors sent to client if they are longer than this value (0 means do not truncate)
       --queryserver-config-txpool-timeout duration                       query server transaction pool timeout, it is how long vttablet waits if tx pool is full (default 1s)
-      --queryserver-config-txpool-waiter-cap int                         query server transaction pool waiter limit, this is the maximum number of transactions that can be queued waiting to get a connection (default 5000)
       --queryserver-config-warn-result-size int                          query server result size warning threshold, warn if number of rows returned from vttablet for non-streaming queries exceeds this
       --queryserver-enable-settings-pool                                 Enable pooling of connections with modified system settings (default true)
       --queryserver-enable-views                                         Enable views support in vttablet.

go/flags/endtoend/vttablet.txt

@@ -276,21 +276,18 @@ Flags:
       --queryserver-config-pool-size int                                 query server read pool size, connection pool is used by regular queries (non streaming, not in a transaction) (default 16)
       --queryserver-config-query-cache-memory int                        query server query cache size in bytes, maximum amount of memory to be used for caching. vttablet analyzes every incoming query and generate a query plan, these plans are being cached in a lru cache. This config controls the capacity of the lru cache. (default 33554432)
       --queryserver-config-query-pool-timeout duration                   query server query pool timeout, it is how long vttablet waits for a connection from the query pool. If set to 0 (default) then the overall query timeout is used instead.
-      --queryserver-config-query-pool-waiter-cap int                     query server query pool waiter limit, this is the maximum number of queries that can be queued waiting to get a connection (default 5000)
       --queryserver-config-query-timeout duration                        query server query timeout, this is the query timeout in vttablet side. If a query takes more than this timeout, it will be killed. (default 30s)
       --queryserver-config-schema-change-signal                          query server schema signal, will signal connected vtgates that schema has changed whenever this is detected. VTGates will need to have -schema_change_signal enabled for this to work (default true)
       --queryserver-config-schema-reload-time duration                   query server schema reload time, how often vttablet reloads schemas from underlying MySQL instance. vttablet keeps table schemas in its own memory and periodically refreshes it from MySQL. This config controls the reload time. (default 30m0s)
       --queryserver-config-stream-buffer-size int                        query server stream buffer size, the maximum number of bytes sent from vttablet for each stream call. It's recommended to keep this value in sync with vtgate's stream_buffer_size. (default 32768)
       --queryserver-config-stream-pool-size int                          query server stream connection pool size, stream pool is used by stream queries: queries that return results to client in a streaming fashion (default 200)
       --queryserver-config-stream-pool-timeout duration                  query server stream pool timeout, it is how long vttablet waits for a connection from the stream pool. If set to 0 (default) then there is no timeout.
-      --queryserver-config-stream-pool-waiter-cap int                    query server stream pool waiter limit, this is the maximum number of streaming queries that can be queued waiting to get a connection
       --queryserver-config-strict-table-acl                              only allow queries that pass table acl checks
       --queryserver-config-terse-errors                                  prevent bind vars from escaping in client error messages
       --queryserver-config-transaction-cap int                           query server transaction cap is the maximum number of transactions allowed to happen at any given point of a time for a single vttablet. E.g. by setting transaction cap to 100, there are at most 100 transactions will be processed by a vttablet and the 101th transaction will be blocked (and fail if it cannot get connection within specified timeout) (default 20)
       --queryserver-config-transaction-timeout duration                  query server transaction timeout, a transaction will be killed if it takes longer than this value (default 30s)
       --queryserver-config-truncate-error-len int                        truncate errors sent to client if they are longer than this value (0 means do not truncate)
       --queryserver-config-txpool-timeout duration                       query server transaction pool timeout, it is how long vttablet waits if tx pool is full (default 1s)
-      --queryserver-config-txpool-waiter-cap int                         query server transaction pool waiter limit, this is the maximum number of transactions that can be queued waiting to get a connection (default 5000)
       --queryserver-config-warn-result-size int                          query server result size warning threshold, warn if number of rows returned from vttablet for non-streaming queries exceeds this
       --queryserver-enable-settings-pool                                 Enable pooling of connections with modified system settings (default true)
       --queryserver-enable-views                                         Enable views support in vttablet.

go/vt/vttablet/tabletserver/tabletenv/config.go

@@ -142,9 +142,10 @@ func registerTabletEnvFlags(fs *pflag.FlagSet) {
 	fs.DurationVar(&currentConfig.TxPool.Timeout, "queryserver-config-txpool-timeout", defaultConfig.TxPool.Timeout, "query server transaction pool timeout, it is how long vttablet waits if tx pool is full")
 	fs.DurationVar(&currentConfig.OltpReadPool.IdleTimeout, "queryserver-config-idle-timeout", defaultConfig.OltpReadPool.IdleTimeout, "query server idle timeout, vttablet manages various mysql connection pools. This config means if a connection has not been used in given idle timeout, this connection will be removed from pool. This effectively manages number of connection objects and optimize the pool performance.")
 	fs.DurationVar(&currentConfig.OltpReadPool.MaxLifetime, "queryserver-config-pool-conn-max-lifetime", defaultConfig.OltpReadPool.MaxLifetime, "query server connection max lifetime, vttablet manages various mysql connection pools. This config means if a connection has lived at least this long, it connection will be removed from pool upon the next time it is returned to the pool.")
-	fs.IntVar(&currentConfig.OltpReadPool.MaxWaiters, "queryserver-config-query-pool-waiter-cap", defaultConfig.OltpReadPool.MaxWaiters, "query server query pool waiter limit, this is the maximum number of queries that can be queued waiting to get a connection")
-	fs.IntVar(&currentConfig.OlapReadPool.MaxWaiters, "queryserver-config-stream-pool-waiter-cap", defaultConfig.OlapReadPool.MaxWaiters, "query server stream pool waiter limit, this is the maximum number of streaming queries that can be queued waiting to get a connection")
-	fs.IntVar(&currentConfig.TxPool.MaxWaiters, "queryserver-config-txpool-waiter-cap", defaultConfig.TxPool.MaxWaiters, "query server transaction pool waiter limit, this is the maximum number of transactions that can be queued waiting to get a connection")
+	fs.MarkDeprecated("queryserver-config-query-pool-waiter-cap", "The new connection pool in v19 does not limit waiter capacity. This flag will be removed in a future release.")
+	fs.MarkDeprecated("queryserver-config-stream-pool-waiter-cap", "The new connection pool in v19 does not limit waiter capacity. This flag will be removed in a future release.")
+	fs.MarkDeprecated("queryserver-config-txpool-waiter-cap", "The new connection pool in v19 does not limit waiter capacity. This flag will be removed in a future release.")
+
 	// tableacl related configurations.
 	fs.BoolVar(&currentConfig.StrictTableACL, "queryserver-config-strict-table-acl", defaultConfig.StrictTableACL, "only allow queries that pass table acl checks")
 	fs.BoolVar(&currentConfig.EnableTableACLDryRun, "queryserver-config-enable-table-acl-dry-run", defaultConfig.EnableTableACLDryRun, "If this flag is enabled, tabletserver will emit monitoring metrics and let the request pass regardless of table acl check results")
@@ -440,7 +441,6 @@ type ConnPoolConfig struct {
 	IdleTimeout        time.Duration `json:"idleTimeoutSeconds,omitempty"`
 	MaxLifetime        time.Duration `json:"maxLifetimeSeconds,omitempty"`
 	PrefillParallelism int           `json:"prefillParallelism,omitempty"`
-	MaxWaiters         int           `json:"maxWaiters,omitempty"`
 }
 
 func (cfg *ConnPoolConfig) MarshalJSON() ([]byte, error) {
@@ -477,7 +477,6 @@ func (cfg *ConnPoolConfig) UnmarshalJSON(data []byte) (err error) {
 		IdleTimeout        string `json:"idleTimeoutSeconds,omitempty"`
 		MaxLifetime        string `json:"maxLifetimeSeconds,omitempty"`
 		PrefillParallelism int    `json:"prefillParallelism,omitempty"`
-		MaxWaiters         int    `json:"maxWaiters,omitempty"`
 	}
 
 	if err := json.Unmarshal(data, &tmp); err != nil {
@@ -507,7 +506,6 @@ func (cfg *ConnPoolConfig) UnmarshalJSON(data []byte) (err error) {
 
 	cfg.Size = tmp.Size
 	cfg.PrefillParallelism = tmp.PrefillParallelism
-	cfg.MaxWaiters = tmp.MaxWaiters
 
 	return nil
 }
@@ -945,7 +943,6 @@ var defaultConfig = TabletConfig{
 	OltpReadPool: ConnPoolConfig{
 		Size:        16,
 		IdleTimeout: 30 * time.Minute,
-		MaxWaiters:  5000,
 	},
 	OlapReadPool: ConnPoolConfig{
 		Size:        200,
@@ -955,7 +952,6 @@ var defaultConfig = TabletConfig{
 		Size:        20,
 		Timeout:     time.Second,
 		IdleTimeout: 30 * time.Minute,
-		MaxWaiters:  5000,
 	},
 	Olap: OlapConfig{
 		TxTimeout: 30 * time.Second,

go/vt/vttablet/tabletserver/tabletenv/config_test.go

@@ -48,7 +48,6 @@ func TestConfigParse(t *testing.T) {
 		},
 		OltpReadPool: ConnPoolConfig{
 			Size:        16,
-			MaxWaiters:  40,
 			Timeout:     10 * time.Second,
 			IdleTimeout: 20 * time.Second,
 			MaxLifetime: 50 * time.Second,
@@ -86,7 +85,6 @@ oltp: {}
 oltpReadPool:
   idleTimeoutSeconds: 20s
   maxLifetimeSeconds: 50s
-  maxWaiters: 40
   size: 16
   timeoutSeconds: 10s
 replicationTracker: {}
@@ -109,7 +107,6 @@ txPool: {}
 oltpReadPool:
   size: 16
   idleTimeoutSeconds: 20s
-  maxWaiters: 40
   maxLifetimeSeconds: 50s
 `)
 	gotCfg := cfg
@@ -148,7 +145,6 @@ oltp:
   txTimeoutSeconds: 30s
 oltpReadPool:
   idleTimeoutSeconds: 30m0s
-  maxWaiters: 5000
   size: 16
 queryCacheDoorkeeper: true
 queryCacheMemory: 33554432
@@ -164,7 +160,6 @@ signalWhenSchemaChange: true
 streamBufferSize: 32768
 txPool:
   idleTimeoutSeconds: 30m0s
-  maxWaiters: 5000
   size: 20
   timeoutSeconds: 1s
 `
@@ -178,7 +173,6 @@ func TestClone(t *testing.T) {
 	cfg1 := &TabletConfig{
 		OltpReadPool: ConnPoolConfig{
 			Size:        16,
-			MaxWaiters:  40,
 			Timeout:     10 * time.Second,
 			IdleTimeout: 20 * time.Second,
 			MaxLifetime: 50 * time.Second,

go/vt/vttablet/tabletserver/tx_pool_test.go

@@ -305,7 +305,6 @@ func TestTxPoolWaitTimeoutError(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().TxPool.Timeout = time.Second
 	// given
 	db, txPool, _, closer := setupWithEnv(t, env)
@@ -428,7 +427,6 @@ func TestTxTimeoutKillsTransactions(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = time.Second
 	_, txPool, limiter, closer := setupWithEnv(t, env)
 	defer closer()
@@ -477,7 +475,6 @@ func TestTxTimeoutDoesNotKillShortLivedTransactions(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = time.Second
 	_, txPool, _, closer := setupWithEnv(t, env)
 	defer closer()
@@ -510,7 +507,6 @@ func TestTxTimeoutKillsOlapTransactions(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = time.Second
 	env.Config().Olap.TxTimeout = 2 * time.Second
 	_, txPool, _, closer := setupWithEnv(t, env)
@@ -548,7 +544,6 @@ func TestTxTimeoutNotEnforcedForZeroLengthTimeouts(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 2
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = 0
 	env.Config().Olap.TxTimeout = 0
 	_, txPool, _, closer := setupWithEnv(t, env)
@@ -591,7 +586,6 @@ func TestTxTimeoutReservedConn(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = time.Second
 	env.Config().Olap.TxTimeout = 2 * time.Second
 	_, txPool, _, closer := setupWithEnv(t, env)
@@ -634,7 +628,6 @@ func TestTxTimeoutReusedReservedConn(t *testing.T) {
 
 	env := newEnv("TabletServerTest")
 	env.Config().TxPool.Size = 1
-	env.Config().TxPool.MaxWaiters = 0
 	env.Config().Oltp.TxTimeout = time.Second
 	env.Config().Olap.TxTimeout = 2 * time.Second
 	_, txPool, _, closer := setupWithEnv(t, env)
@@ -820,7 +813,6 @@ func newEnv(exporterName string) tabletenv.Env {
 	cfg.TxPool.Size = 300
 	cfg.Oltp.TxTimeout = 30 * time.Second
 	cfg.TxPool.Timeout = 40 * time.Second
-	cfg.TxPool.MaxWaiters = 500000
 	cfg.OltpReadPool.IdleTimeout = 30 * time.Second
 	cfg.OlapReadPool.IdleTimeout = 30 * time.Second
 	cfg.TxPool.IdleTimeout = 30 * time.Second