sql/ttl: clarify TTL rate limiter notice

The TTL rate limiter notice incorrectly stated it applies "per leaseholder per table",
when it actually applies "per node per table". This updates the message for accuracy.

Fixes #144463
Epic: none

Release note: none

Author: spilchen

pkg/sql/logictest/testdata/logic_test/cluster_settings

@@ -455,7 +455,7 @@ subtest notice_on_ttl_default_rate_limit
 query T noticetrace
 SET CLUSTER SETTING sql.ttl.default_delete_rate_limit = 90;
 ----
-NOTICE: The TTL rate limit is per leaseholder per table.
+NOTICE: The TTL rate limit is per node per table.
 DETAIL: See the documentation for additional details: https://www.cockroachlabs.com/docs/dev/row-level-ttl#ttl-storage-parameters
 
 statement ok
@@ -464,7 +464,7 @@ SET CLUSTER SETTING sql.ttl.default_delete_rate_limit = 100;
 query T noticetrace
 SET CLUSTER SETTING sql.ttl.default_select_rate_limit = 100;
 ----
-NOTICE: The TTL rate limit is per leaseholder per table.
+NOTICE: The TTL rate limit is per node per table.
 DETAIL: See the documentation for additional details: https://www.cockroachlabs.com/docs/dev/row-level-ttl#ttl-storage-parameters
 
 statement ok

pkg/sql/logictest/testdata/logic_test/row_level_ttl

@@ -906,7 +906,7 @@ CREATE TABLE tbl_set_ttl_params (
   ttl_disable_changefeed_replication = true
 )
 ----
-NOTICE: The TTL rate limit is per leaseholder per table.
+NOTICE: The TTL rate limit is per node per table.
 DETAIL: See the documentation for additional details: https://www.cockroachlabs.com/docs/dev/row-level-ttl#ttl-storage-parameters
 
 onlyif config schema-locked-disabled
@@ -933,7 +933,7 @@ skipif config local-read-committed local-repeatable-read
 query T noticetrace
 ALTER TABLE tbl_set_ttl_params SET (ttl_select_batch_size = 110, ttl_delete_batch_size = 120, ttl_select_rate_limit = 130, ttl_delete_rate_limit = 140, ttl_row_stats_poll_interval = '2m0s')
 ----
-NOTICE: The TTL rate limit is per leaseholder per table.
+NOTICE: The TTL rate limit is per node per table.
 DETAIL: See the documentation for additional details: https://www.cockroachlabs.com/docs/dev/row-level-ttl#ttl-storage-parameters
 
 onlyif config local-read-committed local-repeatable-read

pkg/sql/set_cluster_setting.go

@@ -252,7 +252,7 @@ func printTTLRateLimitNotice(ctx context.Context, p eval.ClientNoticeSender) {
 	p.BufferClientNotice(
 		ctx,
 		errors.WithDetail(
-			pgnotice.Newf("The TTL rate limit is per leaseholder per table."),
+			pgnotice.Newf("The TTL rate limit is per node per table."),
 			ttlDocDetail,
 		),
 	)

pkg/sql/ttl/ttljob/ttljob_processor.go

@@ -234,6 +234,10 @@ func (t *ttlProcessor) work(ctx context.Context, output execinfra.RowReceiver) e
 	// involved in a TTL job.
 	log.Dev.Infof(ctx, "TTL processor started processorID=%d tableID=%d", t.ProcessorID, tableID)
 
+	// Each node sets up two rate limiters (one for SELECT, one for DELETE) per
+	// table. The limiters apply to all ranges assigned to this processor, whether
+	// or not the node is the leaseholder for those ranges.
+
 	selectRateLimit := ttlSpec.SelectRateLimit
 	// Default 0 value to "unlimited" in case job started on node <= v23.2.
 	// todo(sql-foundations): Remove this in 25.1 for consistency with