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mariadb/storage/myisam/mi_locking.c
Monty a6bf4b5807 MDEV-29693 ANALYZE TABLE still flushes table definition cache when engine-independent statistics is used 
This commits enables reloading of engine-independent statistics
without flushing the table from table definition cache.

This is achieved by allowing multiple version of the
TABLE_STATISTICS_CB object and having independent pointers to it in
TABLE and TABLE_SHARE.  The TABLE_STATISTICS_CB object have reference
pointers and are freed when no one is pointing to it anymore.

TABLE's TABLE_STATISTICS_CB pointer is updated to use the
TABLE_SHARE's pointer when read_statistics_for_tables() is called at
the beginning of a query.

Main changes:
- read_statistics_for_table() will allocate an new TABLE_STATISTICS_CB
  object.
- All get_stat_values() functions has a new parameter that tells
  where collected data should be stored. get_stat_values() are not
  using the table_field object anymore to store data.
- All get_stat_values() functions returns 1 if they found any
  data in the statistics tables.

Other things:
- Fixed INSERT DELAYED to not read statistics tables.
- Removed Statistics_state from TABLE_STATISTICS_CB as this is not
  needed anymore as wer are not changing TABLE_SHARE->stats_cb while
  calculating or loading statistics.
- Store values used with store_from_statistical_minmax_field() in
  TABLE_STATISTICS_CB::mem_root. This allowed me to remove the function
  delete_stat_values_for_table_share().
  - Field_blob::store_from_statistical_minmax_field() is implemented
    but is not normally used as we do not yet support EIS statistics
    for blobs. For example Field_blob::update_min() and
    Field_blob::update_max() are not implemented.
    Note that the function can be called if there is an concurrent
    "ALTER TABLE MODIFY field BLOB" running because of a bug in
    ALTER TABLE where it deletes entries from column_stats
    before it has an exclusive lock on the table.
- Use result of field->val_str(&val) as a pointer to the result
  instead of val (safetly fix).
- Allocate memory for collected statistics in THD::mem_root, not in
  in TABLE::mem_root. This could cause the TABLE object to grow if a
  ANALYZE TABLE was run many times on the same table.
  This was done in allocate_statistics_for_table(),
  create_min_max_statistical_fields_for_table() and
  create_min_max_statistical_fields_for_table_share().
- Store in TABLE_STATISTICS_CB::stats_available which statistics was
  found in the statistics tables.
- Removed index_table from class Index_prefix_calc as it was not used.
- Added TABLE_SHARE::LOCK_statistics to ensure we don't load EITS
  in parallel. First thread will load it, others will reuse the
  loaded data.
- Eliminate read_histograms_for_table(). The loading happens within
  read_statistics_for_tables() if histograms are needed.
  One downside is that if we have read statistics without histograms
  before and someone requires histograms, we have to read all statistics
  again (once) from the statistics tables.
  A smaller downside is the need to call alloc_root() for each
  individual histogram. Before we could allocate all the space for
  histograms with a single alloc_root.
- Fixed bug in MyISAM and Aria where they did not properly notice
  that table had changed after analyze table. This was not a problem
  before this patch as then the MyISAM and Aria tables where flushed
  as part of ANALYZE table which did hide this issue.
- Fixed a bug in ANALYZE table where table->records could be seen as 0
  in collect_statistics_for_table(). The effect of this unlikely bug
  was that a full table scan could be done even if
  analyze_sample_percentage was not set to 1.
- Changed multiple mallocs in a row to use multi_alloc_root().
- Added a mutex protection in update_statistics_for_table() to ensure
  that several tables are not updating the statistics at the same time.

Some of the changes in sql_statistics.cc are based on a patch from
Oleg Smirnov <olernov@gmail.com>

Co-authored-by: Oleg Smirnov <olernov@gmail.com>
Co-authored-by: Vicentiu Ciorbaru <cvicentiu@gmail.com>
Reviewer: Sergei Petrunia <sergey@mariadb.com>
2023-08-18 13:28:39 +03:00

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/* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2009, 2018, 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 Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
/*
locking of isam-tables.
reads info from a isam-table. Must be first request before doing any furter
calls to any isamfunktion. Is used to allow many process use the same
isamdatabase.
*/
#include "ftdefs.h"
static void mi_update_status_with_lock(MI_INFO *info);
/* lock table by F_UNLCK, F_RDLCK or F_WRLCK */
int mi_lock_database(MI_INFO *info, int lock_type)
{
int error, mark_crashed= 0;
uint count;
MYISAM_SHARE *share=info->s;
DBUG_ENTER("mi_lock_database");
DBUG_PRINT("enter",("lock_type: %d old lock %d r_locks: %u w_locks: %u "
"global_changed: %d open_count: %u name: '%s'",
lock_type, info->lock_type, share->r_locks,
share->w_locks,
share->global_changed, share->state.open_count,
share->index_file_name));
if (share->options & HA_OPTION_READ_ONLY_DATA ||
info->lock_type == lock_type)
DBUG_RETURN(0);
if (lock_type == F_EXTRA_LCK) /* Used by TMP tables */
{
++share->w_locks;
++share->tot_locks;
info->lock_type= lock_type;
info->s->in_use= list_add(info->s->in_use, &info->in_use);
DBUG_RETURN(0);
}
error= 0;
DBUG_EXECUTE_IF ("mi_lock_database_failure", error= EINVAL;);
if (!info->intern_lock_locked)
mysql_mutex_lock(&share->intern_lock);
if (share->kfile >= 0) /* May only be false on windows */
{
switch (lock_type) {
case F_UNLCK:
ftparser_call_deinitializer(info);
if (info->lock_type == F_RDLCK)
{
count= --share->r_locks;
mi_restore_status(info);
}
else
{
count= --share->w_locks;
mi_update_status_with_lock(info);
}
--share->tot_locks;
if (info->lock_type == F_WRLCK && !share->w_locks &&
!share->delay_key_write && flush_key_blocks(share->key_cache,
share->kfile,
&share->dirty_part_map,
FLUSH_KEEP))
{
mark_crashed= error=my_errno;
mi_print_error(info->s, HA_ERR_CRASHED);
}
if (info->opt_flag & (READ_CACHE_USED | WRITE_CACHE_USED))
{
if (end_io_cache(&info->rec_cache))
{
mark_crashed= error=my_errno;
mi_print_error(info->s, HA_ERR_CRASHED);
}
}
if (!count)
{
DBUG_PRINT("info",("changed: %u w_locks: %u",
(uint) share->changed, share->w_locks));
if (share->changed && !share->w_locks)
{
#ifdef HAVE_MMAP
if ((info->s->mmaped_length != info->s->state.state.data_file_length) &&
(info->s->nonmmaped_inserts > MAX_NONMAPPED_INSERTS))
{
if (info->s->concurrent_insert)
mysql_rwlock_wrlock(&info->s->mmap_lock);
mi_remap_file(info, info->s->state.state.data_file_length);
info->s->nonmmaped_inserts= 0;
if (info->s->concurrent_insert)
mysql_rwlock_unlock(&info->s->mmap_lock);
}
#endif
share->state.process= share->last_process=share->this_process;
share->state.unique= info->last_unique= info->this_unique;
share->state.update_count= info->last_loop= ++info->this_loop;
if (mi_state_info_write(share->kfile, &share->state, 1))
mark_crashed= error=my_errno;
share->changed=0;
if (myisam_flush)
{
if (share->file_map)
my_msync(info->dfile, share->file_map, share->mmaped_length, MS_SYNC);
if (mysql_file_sync(share->kfile, MYF(0)))
mark_crashed= error= my_errno;
if (mysql_file_sync(info->dfile, MYF(0)))
mark_crashed= error= my_errno;
}
else
share->not_flushed=1;
if (error)
mi_print_error(info->s, HA_ERR_CRASHED);
}
if (info->lock_type != F_EXTRA_LCK)
{
if (share->r_locks)
{ /* Only read locks left */
if (my_lock(share->kfile,F_RDLCK,0L,F_TO_EOF,
MYF(MY_WME | MY_SEEK_NOT_DONE)) && !error)
error=my_errno;
}
else if (!share->w_locks)
{ /* No more locks */
if (my_lock(share->kfile,F_UNLCK,0L,F_TO_EOF,
MYF(MY_WME | MY_SEEK_NOT_DONE)) && !error)
error=my_errno;
}
}
}
info->opt_flag&= ~(READ_CACHE_USED | WRITE_CACHE_USED);
info->lock_type= F_UNLCK;
info->s->in_use= list_delete(info->s->in_use, &info->in_use);
break;
case F_RDLCK:
if (info->lock_type == F_WRLCK)
{
/*
Change RW to READONLY
mysqld does not turn write locks to read locks,
so we're never here in mysqld.
*/
if (share->w_locks == 1)
{
if (my_lock(share->kfile,lock_type,0L,F_TO_EOF,
MYF(MY_SEEK_NOT_DONE)))
{
error=my_errno;
break;
}
}
share->w_locks--;
share->r_locks++;
info->lock_type=lock_type;
break;
}
if (!share->r_locks && !share->w_locks)
{
if (my_lock(share->kfile,lock_type,0L,F_TO_EOF,
info->lock_wait | MY_SEEK_NOT_DONE))
{
error=my_errno;
break;
}
if (mi_state_info_read_dsk(share->kfile, &share->state, 1))
{
error=my_errno;
(void) my_lock(share->kfile,F_UNLCK,0L,F_TO_EOF,MYF(MY_SEEK_NOT_DONE));
my_errno=error;
break;
}
}
(void) _mi_test_if_changed(info);
share->r_locks++;
share->tot_locks++;
info->lock_type=lock_type;
info->s->in_use= list_add(info->s->in_use, &info->in_use);
break;
case F_WRLCK:
if (info->lock_type == F_RDLCK)
{ /* Change READONLY to RW */
if (share->r_locks == 1)
{
if (my_lock(share->kfile,lock_type,0L,F_TO_EOF,
MYF(info->lock_wait | MY_SEEK_NOT_DONE)))
{
error=my_errno;
break;
}
share->r_locks--;
share->w_locks++;
info->lock_type=lock_type;
break;
}
}
if (!(share->options & HA_OPTION_READ_ONLY_DATA))
{
if (!share->w_locks)
{
if (my_lock(share->kfile,lock_type,0L,F_TO_EOF,
info->lock_wait | MY_SEEK_NOT_DONE))
{
error=my_errno;
break;
}
if (!share->r_locks)
{
if (mi_state_info_read_dsk(share->kfile, &share->state, 1))
{
error=my_errno;
(void) my_lock(share->kfile,F_UNLCK,0L,F_TO_EOF,
info->lock_wait | MY_SEEK_NOT_DONE);
my_errno=error;
break;
}
}
}
}
(void) _mi_test_if_changed(info);
info->lock_type=lock_type;
info->invalidator=info->s->invalidator;
share->w_locks++;
share->tot_locks++;
DBUG_EXECUTE_IF("simulate_incorrect_share_wlock_value",
DEBUG_SYNC_C("after_share_wlock_increment"););
info->s->in_use= list_add(info->s->in_use, &info->in_use);
break;
default:
break; /* Impossible */
}
}
#ifdef _WIN32
else
{
/*
Check for bad file descriptors if this table is part
of a merge union. Failing to capture this may cause
a crash on windows if the table is renamed and
later on referenced by the merge table.
*/
if ((info->open_flag & HA_OPEN_MERGE_TABLE) && (info->s)->kfile < 0)
{
error = HA_ERR_NO_SUCH_TABLE;
}
}
#endif
if (!info->intern_lock_locked)
mysql_mutex_unlock(&share->intern_lock);
if (mark_crashed)
mi_mark_crashed(info);
DBUG_RETURN(error);
} /* mi_lock_database */
/****************************************************************************
The following functions are called by thr_lock() in threaded applications
****************************************************************************/
/*
Create a copy of the current status for the table
SYNOPSIS
mi_get_status()
param Pointer to Myisam handler
concurrent_insert Set to 1 if we are going to do concurrent inserts
(THR_WRITE_CONCURRENT_INSERT was used)
*/
my_bool mi_get_status(void* param, my_bool concurrent_insert)
{
MI_INFO *info=(MI_INFO*) param;
DBUG_ENTER("mi_get_status");
DBUG_PRINT("info",("name: %s key_file: %lu data_file: %lu rows: %lu concurrent_insert: %d",
info->s->index_file_name,
(ulong) info->s->state.state.key_file_length,
(ulong) info->s->state.state.data_file_length,
(ulong) info->s->state.state.records,
concurrent_insert));
#ifndef DBUG_OFF
if (info->state->key_file_length > info->s->state.state.key_file_length ||
info->state->data_file_length > info->s->state.state.data_file_length)
DBUG_PRINT("warning",("old info: key_file: %ld data_file: %ld",
(long) info->state->key_file_length,
(long) info->state->data_file_length));
#endif
info->save_state=info->s->state.state;
info->state= &info->save_state;
info->append_insert_at_end= concurrent_insert;
if (concurrent_insert)
info->s->state.state.uncacheable= TRUE;
DBUG_RETURN(0);
}
void mi_update_status(void* param)
{
MI_INFO *info=(MI_INFO*) param;
DBUG_ENTER("mi_update_status");
/*
Because someone may have closed the table we point at, we only
update the state if its our own state. This isn't a problem as
we are always pointing at our own lock or at a read lock.
(This is enforced by thr_multi_lock.c)
*/
if (info->state == &info->save_state)
{
DBUG_PRINT("info",
("updating status: key_file: %lu data_file: %lu rows: %lu",
(ulong) info->state->key_file_length,
(ulong) info->state->data_file_length,
(ulong) info->state->records));
if (info->state->key_file_length < info->s->state.state.key_file_length ||
info->state->data_file_length < info->s->state.state.data_file_length)
DBUG_PRINT("warning",("old info: key_file: %ld data_file: %ld",
(long) info->s->state.state.key_file_length,
(long) info->s->state.state.data_file_length));
info->s->state.state= *info->state;
#ifdef HAVE_QUERY_CACHE
DBUG_PRINT("info", ("invalidator... '%s' (status update)",
info->filename));
DBUG_ASSERT(info->s->chst_invalidator != NULL);
(*info->s->chst_invalidator)((const char *)info->filename);
#endif
}
info->state= &info->s->state.state;
info->append_insert_at_end= 0;
/*
We have to flush the write cache here as other threads may start
reading the table before mi_lock_database() is called
*/
if (info->opt_flag & WRITE_CACHE_USED)
{
if (end_io_cache(&info->rec_cache))
{
mi_print_error(info->s, HA_ERR_CRASHED);
mi_mark_crashed(info);
}
info->opt_flag&= ~WRITE_CACHE_USED;
}
DBUG_VOID_RETURN;
}
/*
Same as mi_update_status() but take a lock in the table lock, to protect
against someone calling mi_get_status() from thr_lock() at the same time.
*/
static void mi_update_status_with_lock(MI_INFO *info)
{
my_bool locked= 0;
if (info->state == &info->save_state)
{
locked= 1;
mysql_mutex_lock(&info->s->lock.mutex);
}
mi_update_status(info);
if (locked)
mysql_mutex_unlock(&info->s->lock.mutex);
}
void mi_restore_status(void *param)
{
MI_INFO *info= (MI_INFO*) param;
DBUG_ENTER("mi_restore_status");
DBUG_PRINT("info",("key_file: %ld data_file: %ld",
(long) info->s->state.state.key_file_length,
(long) info->s->state.state.data_file_length));
info->state= &info->s->state.state;
info->append_insert_at_end= 0;
DBUG_VOID_RETURN;
}
void mi_copy_status(void* to,void *from)
{
MI_INFO *info= (MI_INFO*) to;
DBUG_ENTER("mi_copy_status");
info->state= &((MI_INFO*) from)->save_state;
DBUG_PRINT("info",("key_file: %ld data_file: %ld",
(long) info->state->key_file_length,
(long) info->state->data_file_length));
DBUG_VOID_RETURN;
}
/*
Check if should allow concurrent inserts
IMPLEMENTATION
Allow concurrent inserts if we don't have a hole in the table or
if there is no active write lock and there is active read locks and
myisam_concurrent_insert == 2. In this last case the new
row('s) are inserted at end of file instead of filling up the hole.
The last case is to allow one to inserts into a heavily read-used table
even if there is holes.
NOTES
If there is a an rtree indexes in the table, concurrent inserts are
disabled in mi_open()
RETURN
0 ok to use concurrent inserts
1 not ok
*/
my_bool mi_check_status(void *param)
{
MI_INFO *info=(MI_INFO*) param;
DBUG_ENTER("mi_check_status");
DBUG_PRINT("info",("dellink: %ld r_locks: %u w_locks: %u",
(long) info->s->state.dellink, (uint) info->s->r_locks,
(uint) info->s->w_locks));
/*
The test for w_locks == 1 is here because this thread has already done an
external lock (in other words: w_locks == 1 means no other threads has
a write lock)
*/
DBUG_RETURN((my_bool) !(info->s->state.dellink == HA_OFFSET_ERROR ||
(myisam_concurrent_insert == 2 && info->s->r_locks &&
info->s->w_locks == 1)));
}
/**
Fix status for thr_lock_merge()
@param org_table
@param new_table that should point on org_lock. new_table is 0
in case this is the first occurrence of the table in the lock
structure.
*/
void mi_fix_status(MI_INFO *org_table, MI_INFO *new_table)
{
DBUG_ENTER("mi_fix_status");
if (!new_table)
{
/* First in group. Set state as in mi_get_status() */
org_table->state= &org_table->save_state;
}
else
{
/* Set new_table to use state from org_table (first lock of this table) */
new_table->state= org_table->state;
}
DBUG_VOID_RETURN;
}
/****************************************************************************
** functions to read / write the state
****************************************************************************/
int _mi_readinfo(register MI_INFO *info, int lock_type, int check_keybuffer)
{
DBUG_ENTER("_mi_readinfo");
if (info->lock_type == F_UNLCK)
{
MYISAM_SHARE *share=info->s;
if (!share->tot_locks)
{
if (my_lock(share->kfile,lock_type,0L,F_TO_EOF,
info->lock_wait | MY_SEEK_NOT_DONE))
DBUG_RETURN(1);
if (mi_state_info_read_dsk(share->kfile, &share->state, 1))
{
int error= my_errno ? my_errno : HA_ERR_FILE_TOO_SHORT;
(void) my_lock(share->kfile,F_UNLCK,0L,F_TO_EOF,
MYF(MY_SEEK_NOT_DONE));
my_errno= error;
DBUG_RETURN(1);
}
}
if (check_keybuffer)
(void) _mi_test_if_changed(info);
info->invalidator=info->s->invalidator;
}
else if (lock_type == F_WRLCK && info->lock_type == F_RDLCK)
{
my_errno=EACCES; /* Not allowed to change */
DBUG_RETURN(-1); /* when have read_lock() */
}
DBUG_RETURN(0);
} /* _mi_readinfo */
/*
Every isam-function that updates the isam-database MUST end with this
request
*/
int _mi_writeinfo(register MI_INFO *info, uint operation)
{
int error,olderror;
MYISAM_SHARE *share=info->s;
DBUG_ENTER("_mi_writeinfo");
DBUG_PRINT("info",("operation: %u tot_locks: %u", operation,
share->tot_locks));
error=0;
if (share->tot_locks == 0)
{
olderror=my_errno; /* Remember last error */
if (operation)
{ /* Two threads can't be here */
share->state.process= share->last_process= share->this_process;
share->state.unique= info->last_unique= info->this_unique;
share->state.update_count= info->last_loop= ++info->this_loop;
if ((error=mi_state_info_write(share->kfile, &share->state, 1)))
olderror=my_errno;
#ifdef _WIN32
if (myisam_flush)
{
if (share->file_map)
my_msync(info->dfile, share->file_map, share->mmaped_length, MS_SYNC);
mysql_file_sync(share->kfile, 0);
mysql_file_sync(info->dfile, 0);
}
#endif
}
if (!(operation & WRITEINFO_NO_UNLOCK) &&
my_lock(share->kfile,F_UNLCK,0L,F_TO_EOF,
MYF(MY_WME | MY_SEEK_NOT_DONE)) && !error)
DBUG_RETURN(1);
my_errno=olderror;
}
else if (operation)
share->changed= 1; /* Mark keyfile changed */
DBUG_RETURN(error);
} /* _mi_writeinfo */
/* Test if someone has changed the database */
/* (Should be called after readinfo) */
int _mi_test_if_changed(register MI_INFO *info)
{
MYISAM_SHARE *share=info->s;
if (share->state.process != share->last_process ||
share->state.unique != info->last_unique ||
share->state.update_count != info->last_loop)
{ /* Keyfile has changed */
DBUG_PRINT("info",("index file changed"));
if (share->state.process != share->this_process)
(void) flush_key_blocks(share->key_cache, share->kfile,
&share->dirty_part_map, FLUSH_RELEASE);
share->last_process=share->state.process;
info->last_unique= share->state.unique;
info->last_loop= share->state.update_count;
info->update|= HA_STATE_WRITTEN; /* Must use file on next */
info->data_changed= 1; /* For mi_is_changed */
return 1;
}
return (!(info->update & HA_STATE_AKTIV) ||
(info->update & (HA_STATE_WRITTEN | HA_STATE_DELETED |
HA_STATE_KEY_CHANGED)));
} /* _mi_test_if_changed */
/*
Put a mark in the .MYI file that someone is updating the table
DOCUMENTATION
state.open_count in the .MYI file is used the following way:
- For the first change of the .MYI file in this process open_count is
incremented by mi_mark_file_change(). (We have a write lock on the file
when this happens)
- In mi_close() it's decremented by _mi_decrement_open_count() if it
was incremented in the same process.
This mean that if we are the only process using the file, the open_count
tells us if the MYISAM file wasn't properly closed. (This is true if
my_disable_locking is set).
*/
int _mi_mark_file_changed(MI_INFO *info)
{
uchar buff[3];
register MYISAM_SHARE *share=info->s;
uint32 state;
DBUG_ENTER("_mi_mark_file_changed");
state= share->state.changed;
share->state.changed|= (STATE_CHANGED | STATE_NOT_ANALYZED |
STATE_NOT_OPTIMIZED_KEYS);
if (!(state & STATE_CHANGED) || ! share->global_changed)
{
if (!share->global_changed)
{
share->global_changed=1;
share->state.open_count++;
}
if (!share->temporary)
{
mi_int2store(buff,share->state.open_count);
buff[2]=1; /* Mark that it's changed */
DBUG_RETURN((int)mysql_file_pwrite(share->kfile, buff, sizeof(buff),
sizeof(share->state.header),
MYF(MY_NABP)));
}
}
DBUG_RETURN(0);
}
/*
This is only called by close or by extra(HA_FLUSH) if the OS has the pwrite()
call. In these context the following code should be safe!
*/
int _mi_decrement_open_count(MI_INFO *info)
{
uchar buff[2];
register MYISAM_SHARE *share=info->s;
int lock_error=0,write_error=0;
if (share->global_changed)
{
uint old_lock=info->lock_type;
share->global_changed=0;
lock_error= my_disable_locking ? 0 : mi_lock_database(info,F_WRLCK);
/* Its not fatal even if we couldn't get the lock ! */
if (share->state.open_count > 0)
{
share->state.open_count--;
mi_int2store(buff,share->state.open_count);
write_error= (mysql_file_pwrite(share->kfile, buff, sizeof(buff),
sizeof(share->state.header),
MYF(MY_NABP)) != 0);
}
if (!lock_error && !my_disable_locking)
lock_error=mi_lock_database(info,old_lock);
}
return MY_TEST(lock_error || write_error);
}
void _mi_report_crashed_ignore(MI_INFO *file __attribute__((unused)),
const char *message __attribute__((unused)),
const char *sfile __attribute__((unused)),
uint sline __attribute__((unused)))
{
}
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