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- /* Copyright (c) 2013, 2021, Oracle and/or its affiliates.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License, version 2.0,
- as published by the Free Software Foundation.
-
- This program is also distributed with certain software (including
- but not limited to OpenSSL) that is licensed under separate terms,
- as designated in a particular file or component or in included license
- documentation. The authors of MySQL hereby grant you an additional
- permission to link the program and your derivative works with the
- separately licensed software that they have included with MySQL.
-
- 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, version 2.0, 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 */
-
- /**
- @file storage/perfschema/table_uvar_by_thread.cc
- Table USER_VARIABLES_BY_THREAD (implementation).
- */
-
- #include "my_global.h"
- #include "my_thread.h"
- #include "pfs_instr_class.h"
- #include "pfs_column_types.h"
- #include "pfs_column_values.h"
- #include "table_uvar_by_thread.h"
- #include "pfs_global.h"
- #include "pfs_visitor.h"
- #include "pfs_buffer_container.h"
-
- /* Iteration on THD from the sql layer. */
- #include "sql_class.h"
- #include "mysqld_thd_manager.h"
-
- class Find_thd_user_var : public Find_THD_Impl
- {
- public:
- Find_thd_user_var(THD *unsafe_thd)
- : m_unsafe_thd(unsafe_thd)
- {}
-
- virtual bool operator()(THD *thd)
- {
- if (thd != m_unsafe_thd)
- return false;
-
- if (thd->user_vars.records == 0)
- return false;
-
- mysql_mutex_lock(&thd->LOCK_thd_data);
- return true;
- }
-
- private:
- THD *m_unsafe_thd;
- };
-
- void User_variables::materialize(PFS_thread *pfs, THD *thd)
- {
- reset();
-
- m_pfs= pfs;
- m_thread_internal_id= pfs->m_thread_internal_id;
- m_array.reserve(thd->user_vars.records);
-
- user_var_entry *sql_uvar;
-
- uint index= 0;
- User_variable empty;
-
- /* Protects thd->user_vars. */
- mysql_mutex_assert_owner(&thd->LOCK_thd_data);
-
- for (;;)
- {
- sql_uvar= reinterpret_cast<user_var_entry*> (my_hash_element(& thd->user_vars, index));
- if (sql_uvar == NULL)
- break;
-
- /*
- m_array is a container of objects (not pointers)
-
- Naive code can:
- - build locally a new entry
- - add it to the container
- but this causes useless object construction, destruction, and deep copies.
-
- What we do here:
- - add a dummy (empty) entry
- - the container does a deep copy on something empty,
- so that there is nothing to copy.
- - get a reference to the entry added in the container
- - complete -- in place -- the entry initialization
- */
- m_array.push_back(empty);
- User_variable & pfs_uvar= m_array.back();
-
- /* Copy VARIABLE_NAME */
- const char *name= sql_uvar->entry_name.ptr();
- size_t name_length= sql_uvar->entry_name.length();
- assert(name_length <= sizeof(pfs_uvar.m_name));
- pfs_uvar.m_name.make_row(name, name_length);
-
- /* Copy VARIABLE_VALUE */
- my_bool null_value;
- String *str_value;
- String str_buffer;
- uint decimals= 0;
- str_value= sql_uvar->val_str(& null_value, & str_buffer, decimals);
- if (str_value != NULL)
- {
- pfs_uvar.m_value.make_row(str_value->ptr(), str_value->length());
- }
- else
- {
- pfs_uvar.m_value.make_row(NULL, 0);
- }
-
- index++;
- }
- }
-
- THR_LOCK table_uvar_by_thread::m_table_lock;
-
- static const TABLE_FIELD_TYPE field_types[]=
- {
- {
- { C_STRING_WITH_LEN("THREAD_ID") },
- { C_STRING_WITH_LEN("bigint(20)") },
- { NULL, 0}
- },
- {
- { C_STRING_WITH_LEN("VARIABLE_NAME") },
- { C_STRING_WITH_LEN("varchar(64)") },
- { NULL, 0}
- },
- {
- { C_STRING_WITH_LEN("VARIABLE_VALUE") },
- { C_STRING_WITH_LEN("longblob") },
- { NULL, 0}
- }
- };
-
- TABLE_FIELD_DEF
- table_uvar_by_thread::m_field_def=
- { 3, field_types };
-
- PFS_engine_table_share
- table_uvar_by_thread::m_share=
- {
- { C_STRING_WITH_LEN("user_variables_by_thread") },
- &pfs_readonly_acl,
- table_uvar_by_thread::create,
- NULL, /* write_row */
- NULL, /* delete_all_rows */
- table_uvar_by_thread::get_row_count,
- sizeof(pos_t),
- &m_table_lock,
- &m_field_def,
- false, /* checked */
- false /* perpetual */
- };
-
- PFS_engine_table*
- table_uvar_by_thread::create(void)
- {
- return new table_uvar_by_thread();
- }
-
- ha_rows
- table_uvar_by_thread::get_row_count(void)
- {
- /*
- This is an estimate only, not a hard limit.
- The row count is given as a multiple of thread_max,
- so that a join between:
- - table performance_schema.threads
- - table performance_schema.user_variables_by_thread
- will still evaluate relative table sizes correctly
- when deciding a join order.
- */
- return global_thread_container.get_row_count() * 10;
- }
-
- table_uvar_by_thread::table_uvar_by_thread()
- : PFS_engine_table(&m_share, &m_pos),
- m_row_exists(false), m_pos(), m_next_pos()
- {}
-
- void table_uvar_by_thread::reset_position(void)
- {
- m_pos.reset();
- m_next_pos.reset();
- }
-
- int table_uvar_by_thread::rnd_next(void)
- {
- PFS_thread *thread;
- bool has_more_thread= true;
-
- for (m_pos.set_at(&m_next_pos);
- has_more_thread;
- m_pos.next_thread())
- {
- thread= global_thread_container.get(m_pos.m_index_1, & has_more_thread);
- if (thread != NULL)
- {
- if (materialize(thread) == 0)
- {
- const User_variable *uvar= m_THD_cache.get(m_pos.m_index_2);
- if (uvar != NULL)
- {
- make_row(thread, uvar);
- m_next_pos.set_after(&m_pos);
- return 0;
- }
- }
- }
- }
-
- return HA_ERR_END_OF_FILE;
- }
-
- int
- table_uvar_by_thread::rnd_pos(const void *pos)
- {
- PFS_thread *thread;
-
- set_position(pos);
-
- thread= global_thread_container.get(m_pos.m_index_1);
- if (thread != NULL)
- {
- if (materialize(thread) == 0)
- {
- const User_variable *uvar= m_THD_cache.get(m_pos.m_index_2);
- if (uvar != NULL)
- {
- make_row(thread, uvar);
- return 0;
- }
- }
- }
-
- return HA_ERR_RECORD_DELETED;
- }
-
- int table_uvar_by_thread::materialize(PFS_thread *thread)
- {
- if (m_THD_cache.is_materialized(thread))
- return 0;
-
- if (! thread->m_lock.is_populated())
- return 1;
-
- THD *unsafe_thd= thread->m_thd;
- if (unsafe_thd == NULL)
- return 1;
-
- Find_thd_user_var finder(unsafe_thd);
- THD *safe_thd= Global_THD_manager::get_instance()->find_thd(&finder);
- if (safe_thd == NULL)
- return 1;
-
- m_THD_cache.materialize(thread, safe_thd);
- mysql_mutex_unlock(&safe_thd->LOCK_thd_data);
- return 0;
- }
-
- void table_uvar_by_thread
- ::make_row(PFS_thread *thread, const User_variable *uvar)
- {
- pfs_optimistic_state lock;
- m_row_exists= false;
-
- /* Protect this reader against a thread termination */
- thread->m_lock.begin_optimistic_lock(&lock);
-
- m_row.m_thread_internal_id= thread->m_thread_internal_id;
-
- /* uvar is materialized, pointing to it directly. */
- m_row.m_variable_name= & uvar->m_name;
- m_row.m_variable_value= & uvar->m_value;
-
- if (! thread->m_lock.end_optimistic_lock(&lock))
- return;
-
- m_row_exists= true;
- }
-
- int table_uvar_by_thread
- ::read_row_values(TABLE *table,
- unsigned char *buf,
- Field **fields,
- bool read_all)
- {
- Field *f;
-
- if (unlikely(! m_row_exists))
- return HA_ERR_RECORD_DELETED;
-
- /* Set the null bits */
- assert(table->s->null_bytes == 1);
- buf[0]= 0;
-
- assert(m_row.m_variable_name != NULL);
- assert(m_row.m_variable_value != NULL);
-
- for (; (f= *fields) ; fields++)
- {
- if (read_all || bitmap_is_set(table->read_set, f->field_index))
- {
- switch(f->field_index)
- {
- case 0: /* THREAD_ID */
- set_field_ulonglong(f, m_row.m_thread_internal_id);
- break;
- case 1: /* VARIABLE_NAME */
- set_field_varchar_utf8(f,
- m_row.m_variable_name->m_str,
- m_row.m_variable_name->m_length);
- break;
- case 2: /* VARIABLE_VALUE */
- if (m_row.m_variable_value->get_value_length() > 0)
- {
- set_field_blob(f,
- m_row.m_variable_value->get_value(),
- m_row.m_variable_value->get_value_length());
- }
- else
- {
- f->set_null();
- }
- break;
- default:
- assert(false);
- }
- }
- }
-
- return 0;
- }
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