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Message #09648
Re: [Commits] c285dbe: MDEV-5535: Cannot reopen temporary table
Hi, Nirbhay!
I like the approach, there were only few comments, but still there were
some :)
See below.
On May 16, Nirbhay Choubey wrote:
> revision-id: c285dbece2881e1d864bb758d77edc899d568c04 (mariadb-10.1.8-82-gc285dbe)
> parent(s): 222ca736f737e888115c732c8ecad84faf0a2529
> author: Nirbhay Choubey
> committer: Nirbhay Choubey
> timestamp: 2016-05-16 23:59:10 -0400
> message:
>
> MDEV-5535: Cannot reopen temporary table
Would be nice to have a somewhat more verbose commit comment here :)
> diff --git a/mysql-test/t/reopen_temp_table-master.test b/mysql-test/t/reopen_temp_table-master.test
> new file mode 100644
> index 0000000..5ac2ca8
> --- /dev/null
> +++ b/mysql-test/t/reopen_temp_table-master.test
> @@ -0,0 +1 @@
> +--tmpdir=$MYSQLTEST_VARDIR//tmp
Eh... I suppose you mean reopen_temp_table-master.opt
And, in fact, you can simply use reopen_temp_table.opt
Btw, why two slashes? And why do you need to set tmpdir at all?
I suspect you don't - because your tests apparently succeed without it :)
> diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
> index aa2cae5..f729733 100644
> --- a/sql/sql_insert.cc
> +++ b/sql/sql_insert.cc
> @@ -4051,7 +4051,12 @@ static TABLE *create_table_from_items(THD *thd,
> }
> else
> {
> - if (open_temporary_table(thd, create_table))
> + /*
> + The pointer to the newly created temporary table has been stored in
> + table->create_info.
> + */
> + create_table->table= create_info->table;
Where was this happening before you've added an explicit assignment?
(note the assert below - it worked, so somewhere this must've been assigned)
> + if (!create_table->table)
> {
> /*
> This shouldn't happen as creation of temporary table should make
> @@ -4060,7 +4065,6 @@ static TABLE *create_table_from_items(THD *thd,
> */
> DBUG_ASSERT(0);
> }
> - DBUG_ASSERT(create_table->table == create_info->table);
why?
> }
> }
> else
> @@ -4308,6 +4326,27 @@ bool select_create::send_eof()
> DBUG_RETURN(true);
> }
>
> + if (table->s->tmp_table)
> + {
> + /*
> + Now is good time to add the new table to THD temporary tables list.
> + But, before that we need to check if same table got created by the sub-
> + statement.
> + */
> + if (thd->temporary_tables.find_table_share(table->s->table_cache_key.str,
> + table->s->table_cache_key.length))
> + {
> + my_error(ER_TABLE_EXISTS_ERROR, MYF(0), table->alias.c_ptr());
ER_TABLE_EXISTS_ERROR, eh?
I'm not sure it's the best way to solve this. It's an error
that neither CREATE ... IF NOT EXISTS or CREATE OR REPLACE can fix.
But I don't have a good solution for this. If a concurrent thread
would've tried to create a table meanwhile (assuming, non-temporary),
it would wait on the metadata lock, that protects table creation.
so, logically, trying to create a table from inside create table
or trying to drop a used table from stored function (your ER_CANT_REOPEN_TABLE)
should fail with ER_LOCK_DEADLOCK or ER_LOCK_ABORTED - because it's, basically,
trying to get a conflicting metadata lock within the same thread, clearly a
case of the deadlock.
but somehow I believe that returning ER_LOCK_DEADLOCK on a purely myisam
test case with temporary tables - that will be confusing as hell :(
so, ok, let's keep your ER_TABLE_EXISTS_ERROR. But, if possible, please
commit this code (save_tmp_table_share and ER_CANT_REOPEN_TABLE) in a separate
commit, after the main MDEV-5535 commit. To have it clearly distinct
in the history, in case we'll want to change this behaviour later.
> + abort_result_set();
> + DBUG_RETURN(true);
> + }
> + else
> + {
> + DBUG_ASSERT(save_tmp_table_share);
> + thd->temporary_tables.relink_table_share(save_tmp_table_share);
> + }
> + }
> +
> /*
> Do an implicit commit at end of statement for non-temporary
> tables. This can fail, but we should unlock the table
> diff --git a/sql/sql_table.cc b/sql/sql_table.cc
> index 40032c3..93fba14 100644
> --- a/sql/sql_table.cc
> +++ b/sql/sql_table.cc
> @@ -2281,23 +2281,17 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
> */
> DBUG_ASSERT(!(thd->locked_tables_mode &&
> table->open_type != OT_BASE_ONLY &&
> - find_temporary_table(thd, table) &&
> + thd->temporary_tables.find_table(table) &&
> table->mdl_request.ticket != NULL));
>
> - /*
> - drop_temporary_table may return one of the following error codes:
> - . 0 - a temporary table was successfully dropped.
> - . 1 - a temporary table was not found.
> - . -1 - a temporary table is used by an outer statement.
> - */
> if (table->open_type == OT_BASE_ONLY || !is_temporary_table(table))
> error= 1;
> else
> {
> table_creation_was_logged= table->table->s->table_creation_was_logged;
> - if ((error= drop_temporary_table(thd, table->table, &is_trans)) == -1)
> + if (thd->temporary_tables.drop_table(table->table, &is_trans, true))
> {
> - DBUG_ASSERT(thd->in_sub_stmt);
> + error= 1;
> goto err;
Why are changes in this hunk? (comment, assert, -1, etc)
> }
> table->table= 0;
> diff --git a/sql/table.h b/sql/table.h
> index ab39603..8b7c665 100644
> --- a/sql/table.h
> +++ b/sql/table.h
> @@ -600,6 +601,7 @@ struct TABLE_STATISTICS_CB
> struct TABLE_SHARE
> {
> TABLE_SHARE() {} /* Remove gcc warning */
> + TABLE_SHARE *next, *prev;
Eh? Did you forget to remove this?
>
> /** Category of this table. */
> TABLE_CATEGORY table_category;
> diff --git a/sql/temporary_tables.cc b/sql/temporary_tables.cc
> new file mode 100644
> index 0000000..ed5b6b8
> --- /dev/null
> +++ b/sql/temporary_tables.cc
> @@ -0,0 +1,1457 @@
> +/*
> + Copyright (c) 2016 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 02110-1301 USA
> +*/
> +
> +#include "sql_acl.h" /* TMP_TABLE_ACLS */
> +#include "sql_base.h" /* free_io_cache,
> + tdc_create_key */
> +#include "lock.h" /* mysql_lock_remove */
> +#include "log_event.h" /* Query_log_event */
> +#include "sql_show.h" /* append_identifier */
> +#include "sql_handler.h" /* mysql_ha_rm_temporary_tables */
> +#include "temporary_tables.h" /* Temporary_tables */
> +#include "rpl_rli.h" /* rpl_group_info */
> +
> +#define IS_USER_TABLE(A) ((A->tmp_table == TRANSACTIONAL_TMP_TABLE) || \
> + (A->tmp_table == NON_TRANSACTIONAL_TMP_TABLE))
> +
> +
> +/*
> + Initialize the Temporary_tables object. Currently it always returns
> + false (success).
> +
> + @param thd [IN] Thread handle
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::init(THD *thd)
> +{
> + DBUG_ENTER("Temporary_tables::init");
> + this->m_thd= thd;
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Check whether temporary tables exist. The decision is made based on the
> + existence of TMP_TABLE_SHAREs.
> +
> + @param check_slave [IN] Also check the slave temporary tables.
> +
> + @return false Temporary tables exist
> + true No temporary table exist
> +*/
> +bool Temporary_tables::is_empty(bool check_slave)
not a very good idea. You always use it as is_empty(true) or is_empty(false).
that is, the caller always knows whether to check slave or not.
but then you use a common function and it needs to do a completely
unnecessary if() inside. Better to have two functions, like
is_empty() and is_empty_slave(). Or at least make this function inline, then
the compiler will have a chance to optimize it.
> +{
> + DBUG_ENTER("Temporary_tables::is_empty");
> +
> + bool result;
> +
> + if (!m_thd)
> + {
> + DBUG_RETURN(true);
> + }
> +
> + rpl_group_info *rgi_slave= m_thd->rgi_slave;
> +
> + if (check_slave && rgi_slave)
> + {
> + result= (rgi_slave->rli->save_temp_table_shares == NULL) ? true : false;
> + }
> + else
> + {
> + result= (m_table_shares == NULL) ? true : false;
> + }
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> + /*
> + Reset the Temporary_tables object. Currently, it always returns
> + false (success).
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::reset()
> +{
> + DBUG_ENTER("Temporary_tables::reset");
> + m_table_shares= 0;
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Create a temporary table, open it and return the TABLE handle.
> +
> + @param hton [IN] Handlerton
> + @param frm [IN] Binary frm image
> + @param path [IN] File path (without extension)
> + @param db [IN] Schema name
> + @param table_name [IN] Table name
> + @param open_in_engine [IN] Whether open table in SE
> + @param created [OUT] Whether table was created?
can it ever happen for *create==true but a return value is NULL?
or the other way around? how?
> +
> +
> + @return Success A pointer to table object
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::create_and_open_table(handlerton *hton,
> + LEX_CUSTRING *frm,
> + const char *path,
> + const char *db,
> + const char *table_name,
> + bool open_in_engine,
> + bool *created)
> +{
> + DBUG_ENTER("Temporary_tables::create_and_open_table");
> +
> + TMP_TABLE_SHARE *share;
> + TABLE *table= NULL;
> + bool locked;
> +
> + *created= false;
> +
> + if (wait_for_prior_commit())
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + locked= lock_tables();
old code didn't seem to have it here. how comes?
> +
> + if ((share= create_table(hton, frm, path, db, table_name)))
> + {
> + *created= true;
> + table= open_table(share, table_name, open_in_engine);
> + }
> +
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_RETURN(table);
> +}
> +
> +/*
> + Check whether an open table with db/table name is in use.
> +
> + @param db [IN] Database name
> + @param table_name [IN] Table name
> +
> + @return Success Pointer to first used table instance.
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::find_table(const char *db,
> + const char *table_name)
> +{
> + DBUG_ENTER("Temporary_tables::find_table");
> +
> + TABLE *table;
> + char key[MAX_DBKEY_LENGTH];
> + uint key_length;
> + bool locked;
> +
> + if (is_empty(true))
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + key_length= create_table_def_key(key, db, table_name);
> +
> + if (wait_for_prior_commit())
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + locked= lock_tables();
> + table = find_table(key, key_length, TABLE_IN_USE);
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_RETURN(table);
> +}
> +
> +
> +/*
> + Check whether an open table specified in TABLE_LIST is in use.
> +
> + @return tl [IN] TABLE_LIST
> +
> + @return Success Pointer to first used table instance.
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::find_table(const TABLE_LIST *tl)
> +{
> + DBUG_ENTER("Temporary_tables::find_table");
> + TABLE *table= find_table(tl->get_db_name(), tl->get_table_name());
> + DBUG_RETURN(table);
> +}
> +
> +
> +/*
> + Check whether an open table with the specified key is in use.
> + The key, in this case, is not the usual key used for temporary tables.
> + It does not contain server_id & pseudo_thread_id. This function is
> + essentially used use to check whether there is any temporary table
> + which _shadows_ a base table.
> + (see: Query_cache::send_result_to_client())
> +
> + @return Success A pointer to table share object
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::find_table_reduced_key_length(const char *key,
> + uint key_length)
> +{
> + DBUG_ENTER("Temporary_tables::find_table_reduced_key_length");
> +
> + TABLE *result= NULL;
> + bool locked;
> +
> + locked= lock_tables();
> +
> + for (TMP_TABLE_SHARE *share= m_table_shares; share; share= share->next)
> + {
> + if ((share->table_cache_key.length - TMP_TABLE_KEY_EXTRA) == key_length
> + && !memcmp(share->table_cache_key.str, key, key_length))
> + {
> + /*
> + A matching TMP_TABLE_SHARE is found. We now need to find a TABLE
> + instance in use.
> + */
> + for (TABLE *table= share->table; table; table= table->next)
> + {
> + if (table->query_id != 0)
> + {
> + result= table;
> + break;
> + }
> + }
> + }
> + }
> +
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +/*
> + Lookup the TMP_TABLE_SHARE using the given db/table_name.The server_id and
> + pseudo_thread_id used to generate table definition key is taken from m_thd
> + (see create_table_def_key()). Return NULL is none found.
> +
> + @return Success A pointer to table share object
> + Failure NULL
> +*/
> +TMP_TABLE_SHARE *Temporary_tables::find_table_share(const char *db,
> + const char *table_name)
> +{
> + DBUG_ENTER("Temporary_tables::find_table_share");
> +
> + TMP_TABLE_SHARE *share;
> + char key[MAX_DBKEY_LENGTH];
> + uint key_length;
> +
> + key_length= create_table_def_key(key, db, table_name);
> + share= find_table_share(key, key_length);
> +
> + DBUG_RETURN(share);
> +}
> +
> +
> +/*
> + Lookup TMP_TABLE_SHARE using the specified TABLE_LIST element.
> + Return NULL is none found.
> +
> + @return Success A pointer to table share object
> + Failure NULL
> +*/
> +TMP_TABLE_SHARE *Temporary_tables::find_table_share(const TABLE_LIST *tl)
> +{
> + DBUG_ENTER("Temporary_tables::find_table_share");
> + TMP_TABLE_SHARE *share= find_table_share(tl->get_db_name(),
> + tl->get_table_name());
> + DBUG_RETURN(share);
> +}
> +
> +
> +/*
> + Lookup TMP_TABLE_SHARE using the specified table definition key.
> + Return NULL is none found.
> +
> + @return Success A pointer to table share object
> + Failure NULL
> +*/
> +TMP_TABLE_SHARE *Temporary_tables::find_table_share(const char *key,
> + uint key_length)
> +{
> + DBUG_ENTER("Temporary_tables::find_table_share");
> +
> + TMP_TABLE_SHARE *share;
> + TMP_TABLE_SHARE *result= NULL;
> + bool locked;
> +
> + if (wait_for_prior_commit())
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + locked= lock_tables();
> +
> + for (share= m_table_shares; share; share= share->next)
> + {
> + if (share->table_cache_key.length == key_length &&
> + !(memcmp(share->table_cache_key.str, key, key_length)))
> + {
> + result= share;
> + break;
> + }
> + }
> +
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +/*
> + Find a temporary table specified by TABLE_LIST instance in the open table
> + list and prepare its TABLE instance for use. If
> +
> + This function tries to resolve this table in the list of temporary tables
> + of this thread. Temporary tables are thread-local and "shadow" base
> + tables with the same name.
> +
> + @note In most cases one should use Temporary_tables::open_tables() instead
> + of this call.
> +
> + @note One should finalize process of opening temporary table for table
> + list element by calling open_and_process_table(). This function
> + is responsible for table version checking and handling of merge
> + tables.
> +
> + @note We used to check global_read_lock before opening temporary tables.
> + However, that limitation was artificial and is removed now.
> +
> + @param tl [IN] TABLE_LIST
> +
> + @return Error status.
> + @retval false On success. If a temporary table exists for the given
> + key, tl->table is set.
> + @retval TRUE On error. my_error() has been called.
letter case is a bit weird, 'false', but 'TRUE' :)
> +*/
> +bool Temporary_tables::open_table(TABLE_LIST *tl)
> +{
> + DBUG_ENTER("Temporary_tables::open_table");
> +
> + TMP_TABLE_SHARE *share;
> + TABLE *table= NULL;
> + bool locked;
> +
> + /*
> + Code in open_table() assumes that TABLE_LIST::table can be non-zero only
> + for pre-opened temporary tables.
> + */
> + DBUG_ASSERT(tl->table == NULL);
> +
> + /*
> + This function should not be called for cases when derived or I_S
> + tables can be met since table list elements for such tables can
> + have invalid db or table name.
> + Instead Temporary_tables::open_tables() should be used.
> + */
> + DBUG_ASSERT(!tl->derived && !tl->schema_table);
> +
> + if (tl->open_type == OT_BASE_ONLY || is_empty(true))
> + {
> + DBUG_PRINT("info", ("skip_temporary is set or no temporary tables"));
> + DBUG_RETURN(false);
> + }
> +
> + if (wait_for_prior_commit())
this wasn't in the original code
> + {
> + DBUG_RETURN(true);
> + }
> +
> + locked= lock_tables();
neither was this
> +
> + /*
> + First check if there is a reusable open table available in the
> + open table list.
> + */
> + if (find_and_use_table(tl, &table))
> + {
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> + DBUG_RETURN(true); /* Error */
> + }
> +
> + /*
> + No reusable table was found. We will have to open a new instance.
> + */
> + if (!table && (share= find_table_share(tl)))
> + {
> + table= open_table(share, tl->get_table_name(), true);
> + }
> +
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + if (!table)
> + {
> + if (tl->open_type == OT_TEMPORARY_ONLY &&
> + tl->open_strategy == TABLE_LIST::OPEN_NORMAL)
> + {
> + my_error(ER_NO_SUCH_TABLE, MYF(0), tl->db, tl->table_name);
> + DBUG_RETURN(true);
> + }
> + DBUG_RETURN(false);
> + }
> +
> +#ifdef WITH_PARTITION_STORAGE_ENGINE
> + if (tl->partition_names)
> + {
> + /* Partitioned temporary tables is not supported. */
> + DBUG_ASSERT(!table->part_info);
> + my_error(ER_PARTITION_CLAUSE_ON_NONPARTITIONED, MYF(0));
> + DBUG_RETURN(true);
> + }
> +#endif
> +
> + table->query_id= m_thd->query_id;
> + m_thd->thread_specific_used= true;
> +
> + /* It is neither a derived table nor non-updatable view. */
> + tl->updatable= true;
> + tl->table= table;
> +
> + table->init(m_thd, tl);
> +
> + DBUG_PRINT("info", ("Using temporary table"));
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Pre-open temporary tables corresponding to table list elements.
> +
> + @note One should finalize process of opening temporary tables
> + by calling open_tables(). This function is responsible
> + for table version checking and handling of merge tables.
what kind of version checking can there be for temporary tables?
> +
> + @param tl [IN] TABLE_LIST
> +
> + @return false On success. If a temporary table exists
> + for the given element, tl->table is set.
> + true On error. my_error() has been called.
> +*/
> +bool Temporary_tables::open_tables(TABLE_LIST *tl)
> +{
> + DBUG_ENTER("Temporary_tables::open_tables");
> +
> + TABLE_LIST *first_not_own= m_thd->lex->first_not_own_table();
> +
> + for (TABLE_LIST *table= tl; table && table != first_not_own;
> + table= table->next_global)
> + {
> + if (table->derived || table->schema_table)
> + {
> + /*
> + Derived and I_S tables will be handled by a later call to open_tables().
> + */
> + continue;
> + }
> +
> + if ((m_thd->temporary_tables.open_table(table)))
eh? couldn't you simply do
if (open_table(table))
? why do you need this "m_thd->temporary_tables." ?
> + {
> + DBUG_RETURN(true);
> + }
> + }
> +
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Close all temporary tables created by 'CREATE TEMPORARY TABLE' for thread
> + creates one DROP TEMPORARY TABLE binlog event for each pseudo-thread.
> +
> + Temporary tables created in a sql slave is closed by
> + Relay_log_info::close_temporary_tables().
> +
> + @return false Success
> + true Failure
> +*/
> +bool Temporary_tables::close_tables()
> +{
> + DBUG_ENTER("Temporary_tables::close_tables");
> +
> + TMP_TABLE_SHARE *share;
> + TMP_TABLE_SHARE *share_next;
> + TABLE *table, *table_next;
> + bool error= false;
> +
> + if (!m_table_shares)
> + {
> + DBUG_RETURN(false);
> + }
> + DBUG_ASSERT(!m_thd->rgi_slave);
> +
> + /*
> + Ensure we don't have open HANDLERs for tables we are about to close.
> + This is necessary when Temporary_tables::close_tables() is called as
> + part of execution of BINLOG statement (e.g. for format description event).
> + */
> + mysql_ha_rm_temporary_tables(m_thd);
> +
> + /* Close all open temporary tables. */
> + for (TMP_TABLE_SHARE *share= m_table_shares; share; share= share->next)
> + {
> + /* Traverse the table list. */
> + table= share->table;
> + while (table)
> + {
> + table_next= table->next;
> + free_table(table);
> + table= table_next;
> + }
> + }
> +
> + // Write DROP TEMPORARY TABLE query log events to binary log.
> + if (mysql_bin_log.is_open())
> + {
> + error= log_events_and_free_shares();
> + }
> + else
> + {
> + share= m_table_shares;
> + while (share)
> + {
> + share_next= share->next;
> + free_table_share(share, true);
> + share= share_next;
> + }
> + }
> + reset();
> +
> + DBUG_RETURN(error);
> +}
> +
> +
> +/*
> + Rename a temporary table.
> +
> + @param table [IN] Table handle
> + @param db [IN] New schema name
> + @param table_name [IN] New table name
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::rename_table(TABLE *table,
> + const char *db,
> + const char *table_name)
> +{
> + DBUG_ENTER("Temporary_tables::rename_table");
> +
> + char *key;
> + uint key_length;
> +
> + TMP_TABLE_SHARE *share= static_cast<TMP_TABLE_SHARE *>(table->s);
> +
> + if (!(key= (char *) alloc_root(&share->mem_root, MAX_DBKEY_LENGTH)))
> + {
> + DBUG_RETURN(true);
> + }
> +
> + /*
> + Temporary tables are renamed by simply changing their table definition key.
> + */
> + key_length= create_table_def_key(key, db, table_name);
> + share->set_table_cache_key(key, key_length);
> +
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Drop a temporary table.
> +
> + Try to locate the table in the list of open temporary tables.
> + If the table is found:
> + - If the table is locked with LOCK TABLES or by prelocking,
> + unlock it and remove it from the list of locked tables
> + (THD::lock). Currently only transactional temporary tables
> + are locked.
> + - Close the temporary table, remove its .FRM.
> + - Remove the table share from the list of temporary table shares.
> +
> + This function is used to drop user temporary tables, as well as
> + internal tables created in CREATE TEMPORARY TABLE ... SELECT
> + or ALTER TABLE.
> +
> + @param table [IN] Temporary table to be deleted
> + @param is_trans [OUT] Is set to the type of the table:
> + transactional (e.g. innodb) as true or
> + non-transactional (e.g. myisam) as false.
> + @paral delete_table [IN] Whether to delete the table files.
> +
> + @return false Table was dropped
> + true Error
> +*/
> +bool Temporary_tables::drop_table(TABLE *table,
> + bool *is_trans,
> + bool delete_table)
> +{
> + DBUG_ENTER("Temporary_tables::drop_table");
> +
> + TMP_TABLE_SHARE *share;
> + TABLE *tab;
> + TABLE *tab_next;
> + bool result, locked;
> +
> + DBUG_ASSERT(table);
> + DBUG_ASSERT(table->query_id);
> + DBUG_PRINT("tmptable", ("Dropping table: '%s'.'%s'",
> + table->s->db.str, table->s->table_name.str));
> +
> + if (wait_for_prior_commit())
> + {
> + DBUG_RETURN(true);
> + }
old code didn't seem to have that. Why do you?
> +
> + locked= lock_tables();
> +
> + share= static_cast<TMP_TABLE_SHARE *>(table->s);
suggestion: have a function:
static inline TMP_TABLE_SHARE *tmp_table_share(TABLE *t) {
DBUG_ASSERT(t->s->tmp_table);
return static_cast<TMP_TABLE_SHARE *>(table->s);
}
> +
> + /* Table might be in use by some outer statement. */
> + for (tab= share->table; tab; tab= tab->next)
> + {
> + if (tab != table && tab->query_id != 0)
> + {
> + /* Found a table instance in use. This table cannot be be dropped. */
> + my_error(ER_CANT_REOPEN_TABLE, MYF(0), table->alias.c_ptr());
> + result= true;
> + goto end;
> + }
> + }
> +
> + if (is_trans)
> + *is_trans= table->file->has_transactions();
> +
> + /*
> + Iterate over the list of open tables and close all tables referencing the
> + same table share.
the comment sounds a bit odd now, when all open tables are in the
list inside the share.
> + */
> + tab= share->table;
> + while (tab)
> + {
> + tab_next= tab->next;
> + if ((result= free_table(tab))) goto end;
> + tab= tab_next;
> + }
> +
> + result= free_table_share(share, delete_table);
> +
> +end:
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +/**
> + Delete the temporary table files.
> +
> + @param base [IN] Handlerton for table to be deleted.
> + @param path [IN] Path to the table to be deleted (i.e. path
> + to its .frm without an extension).
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::remove_table(handlerton *base, const char *path)
> +{
> + DBUG_ENTER("Temporary_tables::remove_table");
> +
> + bool error= false;
> + handler *file;
> + char frm_path[FN_REFLEN + 1];
> +
> + strxnmov(frm_path, sizeof(frm_path) - 1, path, reg_ext, NullS);
> + if (mysql_file_delete(key_file_frm, frm_path, MYF(0)))
> + {
> + error= true;
> + }
> + file= get_new_handler((TABLE_SHARE*) 0, current_thd->mem_root, base);
> + if (file && file->ha_delete_table(path))
> + {
> + error= true;
> + sql_print_warning("Could not remove temporary table: '%s', error: %d",
> + path, my_errno);
> + }
> +
> + delete file;
> + DBUG_RETURN(error);
> +}
> +
> +
> +/*
> + Mark all temporary tables which were used by the current statement or
> + sub-statement as free for reuse, but only if the query_id can be cleared.
> +
> + @remark For temp tables associated with a open SQL HANDLER the query_id
> + is not reset until the HANDLER is closed.
> +*/
> +void Temporary_tables::mark_tables_as_free_for_reuse()
> +{
> + DBUG_ENTER("Temporary_tables::mark_tables_as_free_for_reuse");
> +
> + bool locked;
> +
> + if (m_thd->query_id == 0)
> + {
> + /*
> + Thread has not executed any statement and has not used any
> + temporary tables.
> + */
> + DBUG_VOID_RETURN;
> + }
> +
> + locked= lock_tables();
> +
> + for (TMP_TABLE_SHARE *share= m_table_shares; share; share= share->next)
> + {
> + for (TABLE *table= share->table; table; table= table->next)
> + {
> + if ((table->query_id == m_thd->query_id) && !table->open_by_handler)
> + {
> + mark_table_as_free_for_reuse(table);
> + }
> + }
> + }
> +
> + if (locked)
> + {
> + DBUG_ASSERT(m_locked);
> + unlock_tables();
> + }
> +
> + DBUG_VOID_RETURN;
> +}
> +
> +
> +/*
> + Reset a single temporary table. Effectively this "closes" one temporary
> + table in a session.
> +
> + @param table Temporary table
> +*/
> +void Temporary_tables::mark_table_as_free_for_reuse(TABLE *table)
> +{
> + DBUG_ENTER("Temporary_tables::mark_table_as_free_for_reuse");
> +
> + DBUG_ASSERT(table->s->tmp_table);
> +
> + table->query_id= 0;
> + table->file->ha_reset();
> +
> + /* Detach temporary MERGE children from temporary parent. */
> + DBUG_ASSERT(table->file);
> + table->file->extra(HA_EXTRA_DETACH_CHILDREN);
> +
> + /*
> + Reset temporary table lock type to it's default value (TL_WRITE).
> +
> + Statements such as INSERT INTO .. SELECT FROM tmp, CREATE TABLE
> + .. SELECT FROM tmp and UPDATE may under some circumstances modify
> + the lock type of the tables participating in the statement. This
> + isn't a problem for non-temporary tables since their lock type is
> + reset at every open, but the same does not occur for temporary
> + tables for historical reasons.
> +
> + Furthermore, the lock type of temporary tables is not really that
> + important because they can only be used by one query at a time.
> + Nonetheless, it's safer from a maintenance point of view to reset
> + the lock type of this singleton TABLE object as to not cause problems
> + when the table is reused.
> +
> + Even under LOCK TABLES mode its okay to reset the lock type as
> + LOCK TABLES is allowed (but ignored) for a temporary table.
> + */
> + table->reginfo.lock_type= TL_WRITE;
> + DBUG_VOID_RETURN;
> +}
> +
> +
> +TMP_TABLE_SHARE *Temporary_tables::unlink_table_share(TABLE_SHARE *share)
> +{
> + DBUG_ENTER("Temporary_tables::unlink_table");
> + TMP_TABLE_SHARE *tmp_table_share;
> +
> + lock_tables();
> + tmp_table_share= static_cast<TMP_TABLE_SHARE *>(share);
> + unlink<TMP_TABLE_SHARE>(&m_table_shares, tmp_table_share);
> + unlock_tables();
> +
> + DBUG_RETURN(tmp_table_share);
> +}
> +
> +
> +void Temporary_tables::relink_table_share(TMP_TABLE_SHARE *share)
> +{
> + DBUG_ENTER("Temporary_tables::relink_table");
> +
> + lock_tables();
> + link<TMP_TABLE_SHARE>(&m_table_shares, share);
> + unlock_tables();
> +
> + DBUG_VOID_RETURN;
> +}
> +
> +
> +/*
> + Create a table definition key.
> +
> + @param key [OUT] Buffer for the key to be created (must
> + be of size MAX_DBKRY_LENGTH)
> + @param db [IN] Database name
> + @param table_name [IN] Table name
> +
> + @return Key length.
> +
> + @note
> + The table key is create from:
> + db + \0
> + table_name + \0
> +
> + Additionally, we add the following to make each temporary table unique on
> + the slave.
> +
> + 4 bytes of master thread id
> + 4 bytes of pseudo thread id
> +*/
> +
> +uint Temporary_tables::create_table_def_key(char *key, const char *db,
> + const char *table_name)
> +{
> + DBUG_ENTER("Temporary_tables::create_table_def_key");
> +
> + uint key_length;
> +
> + key_length= tdc_create_key(key, db, table_name);
> + int4store(key + key_length, m_thd->variables.server_id);
> + int4store(key + key_length + 4, m_thd->variables.pseudo_thread_id);
> + key_length += TMP_TABLE_KEY_EXTRA;
> +
> + DBUG_RETURN(key_length);
> +}
> +
> +
> +/*
> + Create a temporary table.
> +
> + @param hton [IN] Handlerton
> + @param frm [IN] Binary frm image
> + @param path [IN] File path (without extension)
> + @param db [IN] Schema name
> + @param table_name [IN] Table name
> +
> + @return Success A pointer to table share object
> + Failure NULL
> +*/
> +TMP_TABLE_SHARE *Temporary_tables::create_table(handlerton *hton,
> + LEX_CUSTRING *frm,
> + const char *path,
> + const char *db,
> + const char *table_name)
> +{
> + DBUG_ENTER("Temporary_tables::create_table");
> +
> + TMP_TABLE_SHARE *share;
> + char key_cache[MAX_DBKEY_LENGTH];
> + char *saved_key_cache;
> + char *tmp_path;
> + uint key_length;
> + int res;
> +
> + if (wait_for_prior_commit())
you're doing it in almost every method. And when one method calls another,
you're doing it twice. Or thrice. Isn't is too much? (I don't know)
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + /* Create the table definition key for the temporary table. */
> + key_length= create_table_def_key(key_cache, db, table_name);
> +
> + if (!(share= (TMP_TABLE_SHARE *) my_malloc(sizeof(TMP_TABLE_SHARE) +
> + strlen(path) +
> + 1 + key_length, MYF(MY_WME))))
> + {
> + DBUG_RETURN(NULL); /* Out of memory */
> + }
> +
> + tmp_path= (char *)(share + 1);
> + saved_key_cache= strmov(tmp_path, path) + 1;
> + memcpy(saved_key_cache, key_cache, key_length);
> +
> + init_tmp_table_share(m_thd, share, saved_key_cache, key_length,
> + strend(saved_key_cache) + 1, tmp_path);
> +
> + share->table= 0;
> + share->db_plugin= ha_lock_engine(m_thd, hton);
> +
> + /*
> + Prefer using frm image over file. The image might not be available in
> + ALTER TABLE, when the discovering engine took over the ownership (see
> + TABLE::read_frm_image).
> + */
> + res= (frm->str)
> + ? share->init_from_binary_frm_image(m_thd, false, frm->str, frm->length)
> + : open_table_def(m_thd, share, GTS_TABLE | GTS_USE_DISCOVERY);
> +
> + if (res)
> + {
> + /*
> + No need to lock share->mutex as this is not needed for temporary tables.
> + */
> + ::free_table_share(share);
> + my_free(share);
> + DBUG_RETURN(NULL);
> + }
> +
> + share->m_psi= PSI_CALL_get_table_share(true, share);
> +
> + /* Add share to the head of the temporary table share list. */
> + link<TMP_TABLE_SHARE>(&m_table_shares, share);
> +
> + DBUG_RETURN(share);
> +}
> +
> +
> +/*
> + Find a table with the specified key.
> +
> + @param key [IN] Key
> + @param key_length [IN] Key length
> + @param state [IN] Open table state to look for
> +
> + @return Success Pointer to the table instance.
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::find_table(const char *key, uint key_length,
> + Table_state state)
> +{
> + DBUG_ENTER("Temporary_tables::find_table");
> +
> + for (TMP_TABLE_SHARE *share= m_table_shares; share; share= share->next)
> + {
> + if (share->table_cache_key.length == key_length &&
> + !(memcmp(share->table_cache_key.str, key, key_length)))
> + {
> + /* A matching TMP_TABLE_SHARE is found. */
> + for (TABLE *table= share->table; table; table= table->next)
> + {
> + switch (state)
> + {
> + case TABLE_IN_USE:
> + if (table->query_id > 0) DBUG_RETURN(table);
> + break;
> + case TABLE_NOT_IN_USE:
> + if (table->query_id == 0) DBUG_RETURN(table);
> + break;
> + case TABLE_ANY:
> + DBUG_RETURN(table);
> + default: /* Invalid */
> + DBUG_ASSERT(0);
> + DBUG_RETURN(NULL);
> + }
> + }
> + }
> + }
> +
> + DBUG_RETURN(NULL);
> +}
> +
> +
> +/*
> + Find a reusable table in the open table list using the specified TABLE_LIST.
> +
> + @param tl [IN] Table list
> + @param out_table [OUT] Pointer to the requested TABLE object
> +
> + @return Success false
> + Failure true
> +*/
> +bool Temporary_tables::find_and_use_table(const TABLE_LIST *tl,
> + TABLE **out_table)
> +{
> + DBUG_ENTER("Temporary_tables::find_and_use_table");
> +
> + char key[MAX_DBKEY_LENGTH];
> + uint key_length;
> + bool result;
> +
> + key_length= create_table_def_key(key, tl->get_db_name(),
> + tl->get_table_name());
> + result= use_table(find_table(key, key_length, TABLE_NOT_IN_USE), out_table);
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +/*
> + Open a table from the specified TABLE_SHARE with the given alias.
> +
> + @param share [IN] Table share
> + @param alias [IN] Table alias
> + @param open_in_engine [IN] Whether open table in SE
> +
> + @return Success A pointer to table object
> + Failure NULL
> +*/
> +TABLE *Temporary_tables::open_table(TMP_TABLE_SHARE *share,
> + const char *alias,
> + bool open_in_engine)
> +{
> + DBUG_ENTER("Temporary_tables::open_table");
> +
> + TABLE *table;
> +
> + if (wait_for_prior_commit())
> + {
> + DBUG_RETURN(NULL);
> + }
> +
> + if (!(table= (TABLE *) my_malloc(sizeof(TABLE), MYF(MY_WME))))
> + {
> + DBUG_RETURN(NULL); /* Out of memory */
> + }
> +
> + if (open_table_from_share(m_thd, share, alias,
> + (open_in_engine) ?
> + (uint) (HA_OPEN_KEYFILE | HA_OPEN_RNDFILE |
> + HA_GET_INDEX) : 0,
> + (uint) (READ_KEYINFO | COMPUTE_TYPES |
> + EXTRA_RECORD),
> + ha_open_options,
> + table,
> + open_in_engine ? false : true))
> + {
> + my_free(table);
> + DBUG_RETURN(NULL);
> + }
> +
> + table->reginfo.lock_type= TL_WRITE; /* Simulate locked */
> + table->grant.privilege= TMP_TABLE_ACLS;
> + share->tmp_table= (table->file->has_transactions() ?
> + TRANSACTIONAL_TMP_TABLE : NON_TRANSACTIONAL_TMP_TABLE);
> +
> + table->pos_in_table_list= 0;
> + table->query_id= m_thd->query_id;
> +
> + /* Add table to the head of table list. */
> + link<TABLE>(&share->table, table);
I don't know if that's correct. You use TABLE::next and TABLE::prev pointers
to link all tables of a given TMP_TABLE_SHARE into a list. But these
pointers are used to link all tables into a THD::open_tables list
(and may be for other purposes too?).
In fact, TABLE has dedicated pointers for this list that you want:
/**
Links for the list of all TABLE objects for this share.
Declared as private to avoid direct manipulation with those objects.
One should use methods of I_P_List template instead.
*/
TABLE *share_all_next, **share_all_prev;
> +
> + /* Increment Slave_open_temp_table_definitions status variable count. */
> + if (m_thd->rgi_slave)
> + {
> + thread_safe_increment32(&slave_open_temp_tables);
> + }
> +
> + DBUG_PRINT("tmptable", ("Opened table: '%s'.'%s' 0x%lx", table->s->db.str,
> + table->s->table_name.str, (long) table));
> + DBUG_RETURN(table);
> +}
> +
> +
function comment?
> +bool Temporary_tables::use_table(TABLE *table, TABLE **out_table)
> +{
> + DBUG_ENTER("Temporary_tables::use_table");
> +
> + *out_table= table;
> + if (!table)
> + DBUG_RETURN(false);
> +
old code had a block here about "Temporary tables are not safe for parallel
replication". it's in wait_for_prior_commit now, but you aren't calling it
here. why?
> + /*
> + We need to set the THD as it may be different in case of
> + parallel replication
> + */
> + if (table->in_use != m_thd)
> + {
> + table->in_use= m_thd;
> + }
> +
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Close a temporary table.
> +
> + @param table [IN] Table handle
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::close_table(TABLE *table)
> +{
> + DBUG_ENTER("Temporary_tables::close_table");
> +
> + DBUG_PRINT("tmptable", ("closing table: '%s'.'%s' 0x%lx alias: '%s'",
> + table->s->db.str, table->s->table_name.str,
> + (long) table, table->alias.c_ptr()));
> +
> + free_io_cache(table);
don't forget to remove free_io_cache() calls when rebasing your
work on top of the latest 10.2
(they were removed from close_temporary() in 260dd476b05 commit)
> + closefrm(table, false);
> + my_free(table);
> +
> + /* Decrement Slave_open_temp_table_definitions status variable count. */
> + if (m_thd->rgi_slave)
> + {
> + thread_safe_decrement32(&slave_open_temp_tables);
> + }
> +
> + DBUG_RETURN(false);
> +}
> +
> +
> +bool Temporary_tables::wait_for_prior_commit()
> +{
> + DBUG_ENTER("Temporary_tables::wait_for_prior_commit");
> +
> + /*
> + Temporary tables are not safe for parallel replication. They were
> + designed to be visible to one thread only, so have no table locking.
> + Thus there is no protection against two conflicting transactions
> + committing in parallel and things like that.
> +
> + So for now, anything that uses temporary tables will be serialised
> + with anything before it, when using parallel replication.
> +
> + TODO: We might be able to introduce a reference count or something
> + on temp tables, and have slave worker threads wait for it to reach
> + zero before being allowed to use the temp table. Might not be worth
> + it though, as statement-based replication using temporary tables is
> + in any case rather fragile.
> + */
> + if (m_thd->rgi_slave &&
> + m_thd->rgi_slave->rli->save_temp_table_shares &&
> + m_thd->rgi_slave->is_parallel_exec &&
> + m_thd->wait_for_prior_commit())
> + DBUG_RETURN(true);
> +
> + DBUG_RETURN(false);
> +}
> +
> +
> +/*
> + Write query log events with "DROP TEMPORARY TABLES .." for each pseudo
> + thread to the binary log.
> +
> + @return false Success
> + true Error
> +*/
> +bool Temporary_tables::log_events_and_free_shares()
> +{
> + DBUG_ENTER("Temporary_tables::log_events_and_free_shares");
> +
> + DBUG_ASSERT(!m_thd->rgi_slave);
> +
> + TMP_TABLE_SHARE *share;
> + TMP_TABLE_SHARE *next;
> + TMP_TABLE_SHARE *prev_share;
> + // Assume thd->variables.option_bits has OPTION_QUOTE_SHOW_CREATE.
> + bool was_quote_show= true;
> + bool error= false;
> + bool found_user_tables= false;
> + // Better add "IF EXISTS" in case a RESET MASTER has been done.
> + const char stub[]= "DROP /*!40005 TEMPORARY */ TABLE IF EXISTS ";
> + char buf[FN_REFLEN];
> +
> + String s_query(buf, sizeof(buf), system_charset_info);
> + s_query.copy(stub, sizeof(stub) - 1, system_charset_info);
> +
> + /*
> + Insertion sort of temporary tables by pseudo_thread_id to build ordered
> + list of sublists of equal pseudo_thread_id.
> + */
> +
> + for (prev_share= m_table_shares, share= prev_share->next;
> + share;
> + prev_share= share, share= share->next)
> + {
> + TMP_TABLE_SHARE *prev_sorted; /* Same as for prev_share */
> + TMP_TABLE_SHARE *sorted;
> +
> + if (IS_USER_TABLE(share))
> + {
> + if (!found_user_tables)
> + found_user_tables= true;
> +
> + for (prev_sorted= NULL, sorted= m_table_shares;
> + sorted != share;
> + prev_sorted= sorted, sorted= sorted->next)
> + {
> + if (!IS_USER_TABLE(sorted) ||
> + tmpkeyval(sorted) > tmpkeyval(share))
> + {
> + /*
> + Move into the sorted part of the list from the unsorted.
> + */
> + prev_share->next= share->next;
> + share->next= sorted;
> + if (prev_sorted)
> + {
> + prev_sorted->next= share;
> + }
> + else
> + {
> + m_table_shares= share;
> + }
> + share= prev_share;
> + break;
> + }
> + }
> + }
> + }
> +
> + /*
> + We always quote db & table names.
> + */
> + if (found_user_tables &&
> + !(was_quote_show= MY_TEST(m_thd->variables.option_bits &
> + OPTION_QUOTE_SHOW_CREATE)))
> + {
> + m_thd->variables.option_bits |= OPTION_QUOTE_SHOW_CREATE;
> + }
> +
> + /*
> + Scan sorted temporary tables to generate sequence of DROP.
> + */
> + for (share= m_table_shares; share; share= next)
> + {
> + if (IS_USER_TABLE(share))
> + {
> + bool save_thread_specific_used= m_thd->thread_specific_used;
> + my_thread_id save_pseudo_thread_id= m_thd->variables.pseudo_thread_id;
> + char db_buf[FN_REFLEN];
> + String db(db_buf, sizeof(db_buf), system_charset_info);
> +
> + /*
> + Set pseudo_thread_id to be that of the processed table.
> + */
> + m_thd->variables.pseudo_thread_id= tmpkeyval(share);
> +
> + db.copy(share->db.str, share->db.length, system_charset_info);
> + /*
> + Reset s_query() if changed by previous loop.
> + */
> + s_query.length(sizeof(stub) - 1);
> +
> + /*
> + Loop forward through all tables that belong to a common database
> + within the sublist of common pseudo_thread_id to create single
> + DROP query.
> + */
> + for (;
> + share &&
> + IS_USER_TABLE(share) &&
> + tmpkeyval(share) == m_thd->variables.pseudo_thread_id &&
> + share->db.length == db.length() &&
> + memcmp(share->db.str, db.ptr(), db.length()) == 0;
> + share= next)
> + {
> + /*
> + We are going to add ` around the table names and possible more
> + due to special characters.
> + */
> + append_identifier(m_thd, &s_query, share->table_name.str,
> + share->table_name.length);
> + s_query.append(',');
> + next= share->next;
> + remove_table(share->db_type(), share->path.str);
> + ::free_table_share(share);
> + my_free(share);
> + }
> +
> + m_thd->clear_error();
> + CHARSET_INFO *cs_save= m_thd->variables.character_set_client;
> + m_thd->variables.character_set_client= system_charset_info;
> + m_thd->thread_specific_used= true;
> +
> + Query_log_event qinfo(m_thd, s_query.ptr(),
> + s_query.length() - 1 /* to remove trailing ',' */,
> + false, true, false, 0);
> + qinfo.db= db.ptr();
> + qinfo.db_len= db.length();
> + m_thd->variables.character_set_client= cs_save;
> +
> + m_thd->get_stmt_da()->set_overwrite_status(true);
> + if ((error= (mysql_bin_log.write(&qinfo) || error)))
> + {
> + /*
> + If we're here following THD::cleanup, thence the connection
> + has been closed already. So lets print a message to the
> + error log instead of pushing yet another error into the
> + stmt_da.
> +
> + Also, we keep the error flag so that we propagate the error
> + up in the stack. This way, if we're the SQL thread we notice
> + that Temporary_tables::close_tables failed. (Actually, the SQL
> + thread only calls Temporary_tables::close_tables while applying
> + old Start_log_event_v3 events.)
> + */
> + sql_print_error("Failed to write the DROP statement for "
> + "temporary tables to binary log");
> + }
> +
> + m_thd->get_stmt_da()->set_overwrite_status(false);
> + m_thd->variables.pseudo_thread_id= save_pseudo_thread_id;
> + m_thd->thread_specific_used= save_thread_specific_used;
> + }
> + else
> + {
> + next= share->next;
> + free_table_share(share, true);
> + }
> + }
> +
> + if (!was_quote_show)
> + {
> + /*
> + Restore option.
> + */
> + m_thd->variables.option_bits&= ~OPTION_QUOTE_SHOW_CREATE;
> + }
> +
> + DBUG_RETURN(error);
> +}
> +
> +/*
> + Delete the files and free the specified table share.
> +*/
> +bool Temporary_tables::free_table_share(TMP_TABLE_SHARE *share,
> + bool delete_table)
> +{
> + DBUG_ENTER("Temporary_tables::free_table_share");
> +
> + bool result= false;
> +
> + /* Delete the share from table share list */
> + unlink<TMP_TABLE_SHARE>(&m_table_shares, share);
> +
> + if (delete_table)
> + {
> + result= remove_table(share->db_type(), share->path.str);
> + }
> +
> + ::free_table_share(share);
> + my_free(share);
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +/*
> + Free the specified table object.
> +*/
> +bool Temporary_tables::free_table(TABLE *table)
> +{
> + DBUG_ENTER("Temporary_tables::free_table");
> +
> + bool result= false;
> +
> + /* Delete the table from table list */
> + unlink<TABLE>(&static_cast<TMP_TABLE_SHARE *>(table->s)->table, table);
> +
> + /*
> + If LOCK TABLES list is not empty and contains this table, unlock the table
> + and remove the table from this list.
> + */
> + mysql_lock_remove(m_thd, m_thd->lock, table);
> +
> + result= close_table(table);
> +
> + DBUG_RETURN(result);
> +}
> +
> +
> +bool Temporary_tables::lock_tables()
> +{
> + /* Do not proceed if a lock has already been taken. */
> + if (m_locked)
> + {
> + return false;
> + }
> +
> + rpl_group_info *rgi_slave= m_thd->rgi_slave;
> + if (rgi_slave)
> + {
> + mysql_mutex_lock(&rgi_slave->rli->data_lock);
> + m_table_shares= rgi_slave->rli->save_temp_table_shares;
> + m_locked= true;
> + }
> + return m_locked;
> +}
> +
> +
> +void Temporary_tables::unlock_tables()
> +{
> + if (!m_locked)
> + {
> + return;
> + }
> +
> + rpl_group_info *rgi_slave= m_thd->rgi_slave;
> + if (rgi_slave)
> + {
> + rgi_slave->rli->save_temp_table_shares= m_table_shares;
> + mysql_mutex_unlock(&rgi_slave->rli->data_lock);
> + m_locked= false;
> + /*
> + Temporary tables are shared with other by sql execution threads.
> + As a safety measure, clear the pointer to the common area.
> + */
> + reset();
> + }
> + return;
> +}
> +
> diff --git a/sql/temporary_tables.h b/sql/temporary_tables.h
> new file mode 100644
> index 0000000..5a5ed0d
> --- /dev/null
> +++ b/sql/temporary_tables.h
> @@ -0,0 +1,150 @@
> +#ifndef TEMPORARY_TABLES_H
> +#define TEMPORARY_TABLES_H
> +/*
> + Copyright (c) 2016 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 02110-1301 USA
> +*/
> +
> +#define TMP_TABLE_KEY_EXTRA 8
> +
> +struct TMP_TABLE_SHARE: public TABLE_SHARE
> +{
> + /* List of TABLE instances created out of this TABLE_SHARE. */
> + TABLE *table;
Hmm, if you will use TABLE::share_all_prev and TABLE::share_all_next, as
I've written above, you should also use TDC_element that keeps the list
of TABLE's per TABLE_SHARE. And also it has next/prev pointers
to link all TABLE_SHARE's in a list... Perhaps you won't need
TMP_TABLE_SHARE after all? Could you talk with Svoj about it, please?
perhaps you can simply reuse existing TABLE_SHARE code
for linking TABLE_SHARE's into a list and linking TABLE's into
a per-TABLE_SHARE list? TDC_element is a bit of an overkill for
temporary tables, we can either live with that or extract those
bits that you need into a "mini-TDC_element" ? Dunno, best to discuss it
with Svoj.
> +
> + /* Pointers to access TMP_TABLE_SHARE instances. */
> + TMP_TABLE_SHARE *next;
> + TMP_TABLE_SHARE *prev;
> +};
> +
> +
> +class Temporary_tables
> +{
> +public:
> + Temporary_tables() : m_thd(0), m_table_shares(0), m_locked(false)
> + {}
> + bool init(THD *thd);
> + bool is_empty(bool check_slave);
> + bool reset();
> +
> + TABLE *create_and_open_table(handlerton *hton, LEX_CUSTRING *frm,
> + const char *path, const char *db,
> + const char *table_name, bool open_in_engine,
> + bool *created);
> +
> + TABLE *find_table(const char *db, const char *table_name);
> + TABLE *find_table(const TABLE_LIST *tl);
> + TABLE *find_table_reduced_key_length(const char *key, uint key_length);
> +
> + TMP_TABLE_SHARE *find_table_share(const char *db, const char *table_name);
> + TMP_TABLE_SHARE *find_table_share(const TABLE_LIST *tl);
> + TMP_TABLE_SHARE *find_table_share(const char *key, uint key_length);
> +
> + bool open_table(TABLE_LIST *tl);
> + bool open_tables(TABLE_LIST *tl);
> +
> + bool close_tables();
> + bool rename_table(TABLE *table, const char *db, const char *table_name);
> + bool drop_table(TABLE *table, bool *is_trans, bool delete_table);
> + bool remove_table(handlerton *hton, const char *path);
> + void mark_tables_as_free_for_reuse();
> + void mark_table_as_free_for_reuse(TABLE *table);
> +
> + TMP_TABLE_SHARE *unlink_table_share(TABLE_SHARE *share);
> + void relink_table_share(TMP_TABLE_SHARE *share);
> +
> +private:
> + /* THD handler */
> + THD *m_thd;
already discussed
> +
> + /* List of temporary table shares */
> + TMP_TABLE_SHARE *m_table_shares;
> +
> + /* Whether a lock has been acquired. */
> + bool m_locked;
> +
> + /* Opened table states. */
> + enum Table_state {
> + TABLE_IN_USE,
> + TABLE_NOT_IN_USE,
> + TABLE_ANY
> + };
> +
> + uint create_table_def_key(char *key,
> + const char *db,
> + const char *table_name);
> +
> + TMP_TABLE_SHARE *create_table(handlerton *hton,
> + LEX_CUSTRING *frm,
> + const char *path,
> + const char *db,
> + const char *table_name);
> +
> + TABLE *find_table(const char *key, uint key_length, Table_state state);
> +
> + bool find_and_use_table(const TABLE_LIST *tl, TABLE **out_table);
> +
> + TABLE *open_table(TMP_TABLE_SHARE *share, const char *alias,
> + bool open_in_engine);
> +
> + bool use_table(TABLE *table, TABLE **out_table);
> + bool close_table(TABLE *table);
> + bool wait_for_prior_commit();
> + bool log_events_and_free_shares();
> +
> + bool free_table_share(TMP_TABLE_SHARE *share, bool delete_table);
> + bool free_table(TABLE *table);
> +
> + bool lock_tables();
> + void unlock_tables();
> +
> + /* List operations */
> + template <class T>
> + void link(T **list, T *element)
> + {
> + element->next= *list;
> + if (element->next)
> + element->next->prev= element;
> + *list= element;
> + (*list)->prev= 0;
> + }
> +
> + template <class T>
> + void unlink(T **list, T *element)
> + {
> + if (element->prev)
> + {
> + element->prev->next= element->next;
> + if (element->prev->next)
> + element->next->prev= element->prev;
> + }
> + else
> + {
> + DBUG_ASSERT(element == *list);
> +
> + *list= element->next;
> + if (*list)
> + element->next->prev= 0;
> + }
> + }
No need to reinvent the wheel, you can use I_P_List for that.
> +
> + uint tmpkeyval(TMP_TABLE_SHARE *share)
> + {
> + return uint4korr(share->table_cache_key.str +
> + share->table_cache_key.length - 4);
> + }
> +};
> +
> +#endif /* TEMPORARY_TABLES_H */
Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx
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