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MDEV-22523 index->rtr_ssn.mutex is wasting memory

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As part of the SPATIAL INDEX implementation in InnoDB,
dict_index_t was expanded by a rtr_ssn_t field. There are only
3 operations for this field, all protected by rtr_ssn_t::mutex:

* btr_cur_search_to_nth_level() stores the least significant 32 bits
of the 64-bit value that is stored in the index root page.
(This would better be done when the table is opened for the
very first time.)
* rtr_get_new_ssn_id() increments the value by 1.
* rtr_get_current_ssn_id() reads the current value.

All these operations can be implemented equally safely by using
atomic memory access operations.
This commit is contained in:
Marko Mäkelä 2020-05-11 14:23:37 +03:00
parent 4ae778bbec
commit ba3d58ad4c
10 changed files with 17 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
storage/innobase/btr/btr0cur.cc
View File

@ -1475,10 +1475,9 @@ retry_page_get:
node_seq_t root_seq_no;
root_seq_no = page_get_ssn_id(page);
mutex_enter(&(index->rtr_ssn.mutex));
index->rtr_ssn.seq_no = root_seq_no + 1;
mutex_exit(&(index->rtr_ssn.mutex));
my_atomic_store32_explicit(
&index->rtr_ssn, root_seq_no + 1,
MY_MEMORY_ORDER_RELAXED);
}
/* Save the MBR */

2
storage/innobase/dict/dict0mem.cc
View File

@ -741,7 +741,6 @@ dict_mem_index_create(
dict_index_zip_pad_mutex_create_lazy(index);
if (type & DICT_SPATIAL) {
mutex_create(LATCH_ID_RTR_SSN_MUTEX, &index->rtr_ssn.mutex);
index->rtr_track = static_cast<rtr_info_track_t*>(
mem_heap_alloc(
heap,
@ -1067,7 +1066,6 @@ dict_mem_index_free(
rtr_info->index = NULL;
}
mutex_destroy(&index->rtr_ssn.mutex);
mutex_destroy(&index->rtr_track->rtr_active_mutex);
UT_DELETE(index->rtr_track->rtr_active);
}

1
storage/innobase/handler/ha_innodb.cc
View File

@ -626,7 +626,6 @@ static PSI_mutex_info all_innodb_mutexes[] = {
PSI_KEY(rtr_active_mutex),
PSI_KEY(rtr_match_mutex),
PSI_KEY(rtr_path_mutex),
PSI_KEY(rtr_ssn_mutex),
PSI_KEY(trx_sys_mutex),
PSI_KEY(zip_pad_mutex)
};

5
storage/innobase/include/dict0mem.h
View File

@ -2,7 +2,7 @@
Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2012, Facebook Inc.
Copyright (c) 2013, 2019, MariaDB Corporation.
Copyright (c) 2013, 2020, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
@ -964,7 +964,8 @@ struct dict_index_t{
/* in which slot the next sample should be
saved. */
/* @} */
rtr_ssn_t rtr_ssn;/*!< Node sequence number for RTree */
/** R-tree split sequence number */
volatile int32 rtr_ssn;
rtr_info_track_t*
rtr_track;/*!< tracking all R-Tree search cursors */
trx_id_t trx_id; /*!< id of the transaction that created this

20
storage/innobase/include/gis0rtree.ic
View File

@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 2014, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, MariaDB Corporation.
Copyright (c) 2017, 2020, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
@ -132,13 +132,9 @@ rtr_get_new_ssn_id(
/*===============*/
dict_index_t* index) /*!< in/out: the index struct */
{
node_seq_t ssn;
mutex_enter(&(index->rtr_ssn.mutex));
ssn = ++index->rtr_ssn.seq_no;
mutex_exit(&(index->rtr_ssn.mutex));
return(ssn);
node_seq_t ssn= my_atomic_add32_explicit(&index->rtr_ssn, 1,
MY_MEMORY_ORDER_RELAXED);
return ssn + 1;
}
/*****************************************************************//**
Get the current Split Sequence Number.
@ -149,13 +145,7 @@ rtr_get_current_ssn_id(
/*===================*/
dict_index_t* index) /*!< in: index struct */
{
node_seq_t ssn;
mutex_enter(&(index->rtr_ssn.mutex));
ssn = index->rtr_ssn.seq_no;
mutex_exit(&(index->rtr_ssn.mutex));
return(ssn);
return my_atomic_load32_explicit(&index->rtr_ssn, MY_MEMORY_ORDER_RELAXED);
}
/*********************************************************************//**

8
storage/innobase/include/gis0type.h
View File

@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 2014, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2018, MariaDB Corporation.
Copyright (c) 2018, 2020, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
@ -143,12 +143,6 @@ typedef struct rtr_info_track {
rtr_active */
} rtr_info_track_t;
/* Node Sequence Number and mutex protects it. */
typedef struct rtree_ssn {
ib_mutex_t mutex; /*!< mutex protect the seq num */
node_seq_t seq_no; /*!< the SSN (node sequence number) */
} rtr_ssn_t;
/* This is to record the record movement between pages. Used for corresponding
lock movement */
typedef struct rtr_rec_move {

2
storage/innobase/include/sync0sync.h
View File

@ -3,6 +3,7 @@
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2008, Google Inc.
Copyright (c) 2012, Facebook Inc.
Copyright (c) 2020, MariaDB Corporation.
Portions of this file contain modifications contributed and copyrighted by
Google, Inc. Those modifications are gratefully acknowledged and are described
@ -81,7 +82,6 @@ extern mysql_pfs_key_t recv_writer_mutex_key;
extern mysql_pfs_key_t rtr_active_mutex_key;
extern mysql_pfs_key_t rtr_match_mutex_key;
extern mysql_pfs_key_t rtr_path_mutex_key;
extern mysql_pfs_key_t rtr_ssn_mutex_key;
extern mysql_pfs_key_t redo_rseg_mutex_key;
extern mysql_pfs_key_t noredo_rseg_mutex_key;
extern mysql_pfs_key_t page_zip_stat_per_index_mutex_key;

3
storage/innobase/include/sync0types.h
View File

@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, 2018, MariaDB Corporation.
Copyright (c) 2017, 2020, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
@ -327,7 +327,6 @@ enum latch_id_t {
LATCH_ID_REDO_RSEG,
LATCH_ID_NOREDO_RSEG,
LATCH_ID_RW_LOCK_DEBUG,
LATCH_ID_RTR_SSN_MUTEX,
LATCH_ID_RTR_ACTIVE_MUTEX,
LATCH_ID_RTR_MATCH_MUTEX,
LATCH_ID_RTR_PATH_MUTEX,

7
storage/innobase/sync/sync0debug.cc
View File

@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 2014, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, 2018, MariaDB Corporation.
Copyright (c) 2017, 2020, MariaDB Corporation.
Portions of this file contain modifications contributed and copyrighted by
Google, Inc. Those modifications are gratefully acknowledged and are described
@ -383,8 +383,7 @@ private:
{
return(latch->get_id() == LATCH_ID_RTR_ACTIVE_MUTEX
|| latch->get_id() == LATCH_ID_RTR_PATH_MUTEX
|| latch->get_id() == LATCH_ID_RTR_MATCH_MUTEX
|| latch->get_id() == LATCH_ID_RTR_SSN_MUTEX);
|| latch->get_id() == LATCH_ID_RTR_MATCH_MUTEX);
}
private:
@ -1375,8 +1374,6 @@ sync_latch_meta_init()
rw_lock_debug_mutex_key);
#endif /* UNIV_DEBUG */
LATCH_ADD_MUTEX(RTR_SSN_MUTEX, SYNC_ANY_LATCH, rtr_ssn_mutex_key);
LATCH_ADD_MUTEX(RTR_ACTIVE_MUTEX, SYNC_ANY_LATCH,
rtr_active_mutex_key);

2
storage/innobase/sync/sync0sync.cc
View File

@ -2,6 +2,7 @@
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2008, Google Inc.
Copyright (c) 2020, MariaDB Corporation.
Portions of this file contain modifications contributed and copyrighted by
Google, Inc. Those modifications are gratefully acknowledged and are described
@ -73,7 +74,6 @@ mysql_pfs_key_t rw_lock_debug_mutex_key;
mysql_pfs_key_t rtr_active_mutex_key;
mysql_pfs_key_t rtr_match_mutex_key;
mysql_pfs_key_t rtr_path_mutex_key;
mysql_pfs_key_t rtr_ssn_mutex_key;
mysql_pfs_key_t rw_lock_list_mutex_key;
mysql_pfs_key_t rw_lock_mutex_key;
mysql_pfs_key_t srv_innodb_monitor_mutex_key;