From 56489209c63c2c8e26e4d430477fe6e566b26e8d Mon Sep 17 00:00:00 2001
From: Oliver Tan <otan@cockroachlabs.com>
Date: Tue, 19 Oct 2021 15:59:08 +1100
Subject: [PATCH] some more knobs for testing

---
 pkg/sql/ttl.go | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/pkg/sql/ttl.go b/pkg/sql/ttl.go
index 673a8aa088b4..fac3a9d6e349 100644
--- a/pkg/sql/ttl.go
+++ b/pkg/sql/ttl.go
@@ -30,6 +30,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlutil"
 	"github.com/cockroachdb/cockroach/pkg/sql/ttlpb"
 	"github.com/cockroachdb/cockroach/pkg/util/metric"
+	"github.com/cockroachdb/cockroach/pkg/util/quotapool"
 	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
 	"github.com/cockroachdb/errors"
 	pbtypes "github.com/gogo/protobuf/types"
@@ -54,6 +55,18 @@ var ttlDeleteBatchSize = settings.RegisterIntSetting(
 	100,
 )
 
+var ttlActive = settings.RegisterBoolSetting(
+	"job.ttl.enabled",
+	"whether the TTL job is enabled",
+	true,
+)
+
+var ttlRateLimit = settings.RegisterIntSetting(
+	"job.ttl.rate_limit",
+	"maximum deletions per second",
+	5000,
+)
+
 func (t ttlResumer) Resume(ctx context.Context, execCtx interface{}) error {
 	p := execCtx.(JobExecContext)
 	ie := p.ExecCfg().InternalExecutor
@@ -64,8 +77,15 @@ func (t ttlResumer) Resume(ctx context.Context, execCtx interface{}) error {
 	var pkStr string
 	var pkTypes []string
 
+	if !ttlActive.Get(p.ExecCfg().SV()) {
+		return nil
+	}
+
 	metrics := p.ExecCfg().JobRegistry.MetricsStruct().TTL
 
+	limit := ttlRateLimit.Get(p.ExecCfg().SV())
+	rl := quotapool.NewRateLimiter("ttl", quotapool.Limit(limit), limit)
+
 	// TODO(XXX): get dynamic table names.
 	type rangeTarget struct {
 		startKey []string
@@ -244,8 +264,21 @@ func (t ttlResumer) Resume(ctx context.Context, execCtx interface{}) error {
 							until = len(rows)
 						}
 						deleteBatch := rows[i:until]
+						a, err := rl.Acquire(ctx, int64(len(deleteBatch)))
+						if err != nil {
+							return err
+						}
 
 						if err := db.Txn(ctx, func(ctx context.Context, txn *kv.Txn) error {
+							defer a.Consume()
+							if _, err := ie.Exec(
+								ctx,
+								"ttl_delete_low_pri",
+								txn,
+								"SET TRANSACTION PRIORITY LOW",
+							); err != nil {
+								return err
+							}
 							placeholderVals := make([]interface{}, len(pks)*len(deleteBatch))
 							placeholderStr := ""
 							for i, row := range deleteBatch {
@@ -276,7 +309,7 @@ func (t ttlResumer) Resume(ctx context.Context, execCtx interface{}) error {
 								return err
 							}
 							metrics.DeletionDeleteNanos.RecordValue(timeutil.Now().Sub(deletionStartTime).Nanoseconds())
-							metrics.RowDeletions.Inc(int64(len(rows)))
+							metrics.RowDeletions.Inc(int64(len(deleteBatch)))
 							return nil
 						}); err != nil {
 							return err