MDEV-28540 Deprecate and ignore the parameter innodb_prefix_index_cluster_optimization

The parameter innodb_prefix_index_cluster_optimization used to enable an
optimization that was added in cb37c557
and was disabled by default.

We will unconditionally enable the extension and mark the parameter
as deprecated.

Related to this, the counters
Innodb_secondary_index_triggered_cluster_reads and
Innodb_secondary_index_triggered_cluster_reads_avoided
allowed to determine the usefulness of this optimization.

Now that the configuration parameter is disabled, the counters
do not serve any useful purpose and can be removed.

row_search_with_covering_prefix(): Fix a bug that caused an
incorrect result to be returned.

mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result

@@ -70,8 +70,6 @@ buffer_pool_pages_free	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	N
 buffer_pages_created	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages created (innodb_pages_created)
 buffer_pages_written	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages written (innodb_pages_written)
 buffer_pages_read	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages read (innodb_pages_read)
-buffer_index_sec_rec_cluster_reads	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of secondary record reads triggered cluster read
-buffer_index_sec_rec_cluster_reads_avoided	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of secondary record reads avoided triggering cluster read
 buffer_data_reads	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Amount of data read in bytes (innodb_data_reads)
 buffer_data_written	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Amount of data written in bytes (innodb_data_written)
 buffer_flush_batch_scanned	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	set_owner	Total pages scanned as part of flush batch

mysql-test/suite/innodb/r/innodb_status_variables.result

@@ -98,8 +98,6 @@ INNODB_INSTANT_ALTER_COLUMN
 INNODB_ONLINEDDL_ROWLOG_ROWS
 INNODB_ONLINEDDL_ROWLOG_PCT_USED
 INNODB_ONLINEDDL_PCT_PROGRESS
-INNODB_SECONDARY_INDEX_TRIGGERED_CLUSTER_READS
-INNODB_SECONDARY_INDEX_TRIGGERED_CLUSTER_READS_AVOIDED
 INNODB_ENCRYPTION_ROTATION_PAGES_READ_FROM_CACHE
 INNODB_ENCRYPTION_ROTATION_PAGES_READ_FROM_DISK
 INNODB_ENCRYPTION_ROTATION_PAGES_MODIFIED

mysql-test/suite/innodb/r/monitor.result

@@ -36,8 +36,6 @@ buffer_pool_pages_free	disabled
 buffer_pages_created	disabled
 buffer_pages_written	disabled
 buffer_pages_read	disabled
-buffer_index_sec_rec_cluster_reads	disabled
-buffer_index_sec_rec_cluster_reads_avoided	disabled
 buffer_data_reads	disabled
 buffer_data_written	disabled
 buffer_flush_batch_scanned	disabled

mysql-test/suite/sys_vars/r/innodb_prefix_index_cluster_optimization_basic.result

-SET @start_global_value = @@global.innodb_prefix_index_cluster_optimization;
-SELECT @start_global_value;
-@start_global_value
-0
-#
-# exists as global only
-#
-Valid values are 'ON' and 'OFF'
-select @@global.innodb_prefix_index_cluster_optimization in (0, 1);
-@@global.innodb_prefix_index_cluster_optimization in (0, 1)
-1
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-0
-select @@session.innodb_prefix_index_cluster_optimization;
-ERROR HY000: Variable 'innodb_prefix_index_cluster_optimization' is a GLOBAL variable
-show global variables like 'innodb_prefix_index_cluster_optimization';
-Variable_name	Value
-innodb_prefix_index_cluster_optimization	OFF
-show session variables like 'innodb_prefix_index_cluster_optimization';
-Variable_name	Value
-innodb_prefix_index_cluster_optimization	OFF
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-#
-# show that it's writable
-#
-set global innodb_prefix_index_cluster_optimization = 'OFF';
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-0
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-set @@global.innodb_prefix_index_cluster_optimization = 'ON';
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-1
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-set global innodb_prefix_index_cluster_optimization = 0;
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-0
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	OFF
-set @@global.innodb_prefix_index_cluster_optimization = 1;
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-1
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-set session innodb_prefix_index_cluster_optimization = 'OFF';
-ERROR HY000: Variable 'innodb_prefix_index_cluster_optimization' is a GLOBAL variable and should be set with SET GLOBAL
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-1
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-set @@session.innodb_prefix_index_cluster_optimization = 'ON';
-ERROR HY000: Variable 'innodb_prefix_index_cluster_optimization' is a GLOBAL variable and should be set with SET GLOBAL
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-1
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-#
-# incorrect types
-#
-set global innodb_prefix_index_cluster_optimization = 1.1;
-ERROR 42000: Incorrect argument type to variable 'innodb_prefix_index_cluster_optimization'
-set global innodb_prefix_index_cluster_optimization = 1e1;
-ERROR 42000: Incorrect argument type to variable 'innodb_prefix_index_cluster_optimization'
-set global innodb_prefix_index_cluster_optimization = 2;
-ERROR 42000: Variable 'innodb_prefix_index_cluster_optimization' can't be set to the value of '2'
-set global innodb_prefix_index_cluster_optimization = -3;
-ERROR 42000: Variable 'innodb_prefix_index_cluster_optimization' can't be set to the value of '-3'
-select @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-1
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION	ON
-set global innodb_prefix_index_cluster_optimization = 'AUTO';
-ERROR 42000: Variable 'innodb_prefix_index_cluster_optimization' can't be set to the value of 'AUTO'
-#
-# Cleanup
-#
-SET @@global.innodb_prefix_index_cluster_optimization = @start_global_value;
-SELECT @@global.innodb_prefix_index_cluster_optimization;
-@@global.innodb_prefix_index_cluster_optimization
-0

mysql-test/suite/sys_vars/r/sysvars_innodb.result

@@ -1256,10 +1256,10 @@ READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	INNODB_PREFIX_INDEX_CLUSTER_OPTIMIZATION
 SESSION_VALUE	NULL
-DEFAULT_VALUE	OFF
+DEFAULT_VALUE	ON
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Enable prefix optimization to sometimes avoid cluster index lookups.
+VARIABLE_COMMENT	Deprecated parameter with no effect
 NUMERIC_MIN_VALUE	NULL
 NUMERIC_MAX_VALUE	NULL
 NUMERIC_BLOCK_SIZE	NULL

mysql-test/suite/sys_vars/t/innodb_prefix_index_cluster_optimization_basic.test

---source include/have_innodb.inc
-
-SET @start_global_value = @@global.innodb_prefix_index_cluster_optimization;
-SELECT @start_global_value;
-
---echo #
---echo # exists as global only
---echo #
-
---echo Valid values are 'ON' and 'OFF'
-select @@global.innodb_prefix_index_cluster_optimization in (0, 1);
-select @@global.innodb_prefix_index_cluster_optimization;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_prefix_index_cluster_optimization;
-show global variables like 'innodb_prefix_index_cluster_optimization';
-show session variables like 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-
---echo #
---echo # show that it's writable
---echo #
-
-set global innodb_prefix_index_cluster_optimization = 'OFF';
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-set @@global.innodb_prefix_index_cluster_optimization = 'ON';
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-set global innodb_prefix_index_cluster_optimization = 0;
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-set @@global.innodb_prefix_index_cluster_optimization = 1;
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-
---error ER_GLOBAL_VARIABLE
-set session innodb_prefix_index_cluster_optimization = 'OFF';
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-
---error ER_GLOBAL_VARIABLE
-set @@session.innodb_prefix_index_cluster_optimization = 'ON';
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-
---echo #
---echo # incorrect types
---echo #
-
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_prefix_index_cluster_optimization = 1.1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_prefix_index_cluster_optimization = 1e1;
---error ER_WRONG_VALUE_FOR_VAR
-set global innodb_prefix_index_cluster_optimization = 2;
---error ER_WRONG_VALUE_FOR_VAR
-set global innodb_prefix_index_cluster_optimization = -3;
-select @@global.innodb_prefix_index_cluster_optimization;
-select * from information_schema.global_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
-select * from information_schema.session_variables where variable_name = 'innodb_prefix_index_cluster_optimization';
---error ER_WRONG_VALUE_FOR_VAR
-set global innodb_prefix_index_cluster_optimization = 'AUTO';
-
---echo #
---echo # Cleanup
---echo #
-
-SET @@global.innodb_prefix_index_cluster_optimization = @start_global_value;
-SELECT @@global.innodb_prefix_index_cluster_optimization;

storage/innobase/handler/ha_innodb.cc

@@ -1052,13 +1052,6 @@ static SHOW_VAR innodb_status_variables[]= {
   {"onlineddl_pct_progress",
    &export_vars.innodb_onlineddl_pct_progress, SHOW_SIZE_T},
 
-  /* Times secondary index lookup triggered cluster lookup and
-  times prefix optimization avoided triggering cluster lookup */
-  {"secondary_index_triggered_cluster_reads",
-   &export_vars.innodb_sec_rec_cluster_reads, SHOW_SIZE_T},
-  {"secondary_index_triggered_cluster_reads_avoided",
-   &export_vars.innodb_sec_rec_cluster_reads_avoided, SHOW_SIZE_T},
-
   /* Encryption */
   {"encryption_rotation_pages_read_from_cache",
    &export_vars.innodb_encryption_rotation_pages_read_from_cache, SHOW_SIZE_T},
@@ -19349,11 +19342,13 @@ static MYSQL_SYSVAR_UINT(spin_wait_delay, srv_spin_wait_delay,
   "Maximum delay between polling for a spin lock (4 by default)",
   NULL, NULL, 4, 0, 6000, 0);
 
+static my_bool innodb_prefix_index_cluster_optimization;
+
 static MYSQL_SYSVAR_BOOL(prefix_index_cluster_optimization,
-  srv_prefix_index_cluster_optimization,
-  PLUGIN_VAR_OPCMDARG,
-  "Enable prefix optimization to sometimes avoid cluster index lookups.",
-  NULL, NULL, FALSE);
+  innodb_prefix_index_cluster_optimization,
+  PLUGIN_VAR_OPCMDARG | PLUGIN_VAR_DEPRECATED,
+  "Deprecated parameter with no effect",
+  nullptr, nullptr, TRUE);
 
 static MYSQL_SYSVAR_STR(data_file_path, innobase_data_file_path,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,

storage/innobase/include/srv0mon.h

@@ -175,8 +175,6 @@ enum monitor_id_t {
 	MONITOR_OVLD_PAGE_CREATED,
 	MONITOR_OVLD_PAGES_WRITTEN,
 	MONITOR_OVLD_PAGES_READ,
-	MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS,
-	MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS_AVOIDED,
 	MONITOR_OVLD_BYTE_READ,
 	MONITOR_OVLD_BYTE_WRITTEN,
 	MONITOR_FLUSH_BATCH_SCANNED,

storage/innobase/include/srv0srv.h

@@ -116,12 +116,6 @@ struct srv_stats_t
 	/** Number of data read in total (in bytes) */
 	ulint_ctr_1_t		data_read;
 
-	/** Number of times secondary index lookup triggered cluster lookup */
-	ulint_ctr_n_t		n_sec_rec_cluster_reads;
-
-	/** Number of times prefix optimization avoided triggering cluster lookup */
-	ulint_ctr_n_t		n_sec_rec_cluster_reads_avoided;
-
 	/** Number of encryption_get_latest_key_version calls */
 	ulint_ctr_n_t		n_key_requests;
 
@@ -227,10 +221,6 @@ extern ulong	srv_purge_rseg_truncate_frequency;
 /** Enable or Disable Truncate of UNDO tablespace. */
 extern my_bool	srv_undo_log_truncate;
 
-/* Optimize prefix index queries to skip cluster index lookup when possible */
-/* Enables or disables this prefix optimization.  Disabled by default. */
-extern my_bool	srv_prefix_index_cluster_optimization;
-
 /** Default size of UNDO tablespace (10MiB for innodb_page_size=16k) */
 constexpr ulint SRV_UNDO_TABLESPACE_SIZE_IN_PAGES= (10U << 20) /
   UNIV_PAGE_SIZE_DEF;
@@ -727,9 +717,6 @@ struct export_var_t{
 	/* Number of temporary tablespace pages decrypted */
 	ib_int64_t innodb_n_temp_blocks_decrypted;
 
-	ulint innodb_sec_rec_cluster_reads;	/*!< srv_sec_rec_cluster_reads */
-	ulint innodb_sec_rec_cluster_reads_avoided;/*!< srv_sec_rec_cluster_reads_avoided */
-
 	ulint innodb_encryption_rotation_pages_read_from_cache;
 	ulint innodb_encryption_rotation_pages_read_from_disk;
 	ulint innodb_encryption_rotation_pages_modified;

storage/innobase/row/row0sel.cc

@@ -3337,9 +3337,6 @@ Row_sel_get_clust_rec_for_mysql::operator()(
 	*out_rec = NULL;
 	trx = thr_get_trx(thr);
 
-	srv_stats.n_sec_rec_cluster_reads.inc(
-		thd_get_thread_id(trx->mysql_thd));
-
 	row_build_row_ref_in_tuple(prebuilt->clust_ref, rec,
 				   sec_index, *offsets);
 
@@ -4205,11 +4202,9 @@ bool row_search_with_covering_prefix(
 	const dict_index_t*	index = prebuilt->index;
 	ut_ad(!dict_index_is_clust(index));
 
-	if (dict_index_is_spatial(index)) {
-		return false;
-	}
-
-	if (!srv_prefix_index_cluster_optimization) {
+	/* In ha_innobase::build_template() we choose to access the
+	whole row when using exclusive row locks. */
+	if (prebuilt->select_lock_type == LOCK_X || !index->is_btree()) {
 		return false;
 	}
 
@@ -4276,7 +4271,6 @@ bool row_search_with_covering_prefix(
 		ut_a(templ->rec_field_no != ULINT_UNDEFINED);
 	}
 
-	srv_stats.n_sec_rec_cluster_reads_avoided.inc();
 	return true;
 }
 

storage/innobase/srv/srv0mon.cc

@@ -278,18 +278,6 @@ static monitor_info_t	innodb_counter_info[] =
 	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
 	 MONITOR_DEFAULT_START, MONITOR_OVLD_PAGES_READ},
 
-	{"buffer_index_sec_rec_cluster_reads", "buffer",
-	 "Number of secondary record reads triggered cluster read",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS},
-
-	{"buffer_index_sec_rec_cluster_reads_avoided", "buffer",
-	 "Number of secondary record reads avoided triggering cluster read",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS_AVOIDED},
-
 	{"buffer_data_reads", "buffer",
 	 "Amount of data read in bytes (innodb_data_reads)",
 	 static_cast<monitor_type_t>(
@@ -1425,16 +1413,6 @@ srv_mon_process_existing_counter(
 		value = buf_pool.stat.n_pages_read;
 		break;
 
-	/* Number of times secondary index lookup triggered cluster lookup */
-	case MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS:
-		value = srv_stats.n_sec_rec_cluster_reads;
-		break;
-	/* Number of times prefix optimization avoided triggering cluster
-	lookup */
-	case MONITOR_OVLD_INDEX_SEC_REC_CLUSTER_READS_AVOIDED:
-		value = srv_stats.n_sec_rec_cluster_reads_avoided;
-		break;
-
 	/* innodb_data_reads, the total number of data reads */
 	case MONITOR_OVLD_BYTE_READ:
 		value = srv_stats.data_read;

storage/innobase/srv/srv0srv.cc

@@ -291,10 +291,6 @@ uint	srv_fast_shutdown;
 /** copy of innodb_status_file; generate a innodb_status.<pid> file */
 ibool	srv_innodb_status;
 
-/** innodb_prefix_index_cluster_optimization; whether to optimize
-prefix index queries to skip cluster index lookup when possible */
-my_bool	srv_prefix_index_cluster_optimization;
-
 /** innodb_stats_transient_sample_pages;
 When estimating number of different key values in an index, sample
 this many index pages, there are 2 ways to calculate statistics:
@@ -1031,11 +1027,6 @@ srv_export_innodb_status(void)
 	export_vars.innodb_onlineddl_rowlog_pct_used = onlineddl_rowlog_pct_used;
 	export_vars.innodb_onlineddl_pct_progress = onlineddl_pct_progress;
 
-	export_vars.innodb_sec_rec_cluster_reads =
-		srv_stats.n_sec_rec_cluster_reads;
-	export_vars.innodb_sec_rec_cluster_reads_avoided =
-		srv_stats.n_sec_rec_cluster_reads_avoided;
-
 	if (!srv_read_only_mode) {
 		export_vars.innodb_encryption_rotation_pages_read_from_cache =
 			crypt_stat.pages_read_from_cache;

storage/rocksdb/mysql-test/rocksdb/r/innodb_i_s_tables_disabled.result

@@ -52,8 +52,6 @@ buffer_pool_pages_free	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	N
 buffer_pages_created	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages created (innodb_pages_created)
 buffer_pages_written	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages written (innodb_pages_written)
 buffer_pages_read	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of pages read (innodb_pages_read)
-buffer_index_sec_rec_cluster_reads	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of secondary record reads triggered cluster read
-buffer_index_sec_rec_cluster_reads_avoided	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of secondary record reads avoided triggering cluster read
 buffer_data_reads	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Amount of data read in bytes (innodb_data_reads)
 buffer_data_written	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Amount of data written in bytes (innodb_data_written)
 buffer_flush_batch_scanned	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	set_owner	Total pages scanned as part of flush batch