Merge #110332

110332: rangefeed: increase the txn push interval to 1 second r=erikgrinaker a=erikgrinaker

With a default rangefeed closed timestamp interval of 3 seconds, and a default txn age of 10 seconds, there doesn't appear to be a good reason for attempting to push txns every 250 milliseconds.

This patch increases the push interval to 1 second, and adds an environment variable `COCKROACH_RANGEFEED_PUSH_TXNS_INTERVAL` to control it.

Epic: none
Release note (ops change): Rangefeeds regularly attempt to push long-running transactions to a future timestamp in order to emit checkpoints. The interval at which this is attempted has been increased from 250 milliseconds to 1 seconds. This is now configurable via the environment variable `COCKROACH_RANGEFEED_PUSH_TXNS_INTERVAL`.

Co-authored-by: Erik Grinaker <grinaker@cockroachlabs.com>

Author: craig[bot]

pkg/kv/kvserver/rangefeed/processor.go

@@ -19,21 +19,25 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/kv/kvpb"
 	"github.com/cockroachdb/cockroach/pkg/roachpb"
 	"github.com/cockroachdb/cockroach/pkg/storage/enginepb"
+	"github.com/cockroachdb/cockroach/pkg/util/envutil"
 	"github.com/cockroachdb/cockroach/pkg/util/future"
 	"github.com/cockroachdb/cockroach/pkg/util/hlc"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/cockroach/pkg/util/stop"
 	"github.com/cockroachdb/errors"
 )
 
-const (
+var (
 	// DefaultPushTxnsInterval is the default interval at which a Processor will
 	// push all transactions in the unresolvedIntentQueue that are above the age
 	// specified by PushTxnsAge.
-	DefaultPushTxnsInterval = 250 * time.Millisecond
+	DefaultPushTxnsInterval = envutil.EnvOrDefaultDuration(
+		"COCKROACH_RANGEFEED_PUSH_TXNS_INTERVAL", time.Second)
+
 	// defaultPushTxnsAge is the default age at which a Processor will begin to
 	// consider a transaction old enough to push.
-	defaultPushTxnsAge = 10 * time.Second
+	defaultPushTxnsAge = envutil.EnvOrDefaultDuration(
+		"COCKROACH_RANGEFEED_PUSH_TXNS_AGE", 10*time.Second)
 )
 
 // newErrBufferCapacityExceeded creates an error that is returned to subscribers