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polardbxengine/sql/dd/info_schema/metadata.cc

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/* Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
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 */
/*
This file contains code that updates data dictionary tables
with the metadata of INFORMATION_SCHEMA tables.
There are two types of I_S tables.
- I_S tables exposed by the server.
- I_S tables exposed by the plugin.
*/
#include "sql/dd/info_schema/metadata.h"
#include <sys/types.h>
#include <algorithm>
#include <atomic>
#include <memory>
#include <string>
#include <vector>
#include "field_types.h" // enum_field_types
#include "lex_string.h"
#include "m_string.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_loglevel.h"
#include "my_sys.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/components/services/log_shared.h"
#include "mysql/plugin.h"
#include "sql/dd/cache/dictionary_client.h" // dd::cache::Dictionary_client
#include "sql/dd/dd_schema.h" // dd::Schema_MDL_locker
#include "sql/dd/dd_table.h" // dd::get_sql_type_by_field_info
#include "sql/dd/impl/bootstrap/bootstrap_ctx.h" // dd::bootstrap::DD_boot...
#include "sql/dd/impl/bootstrap/bootstrapper.h" // dd::Column
#include "sql/dd/impl/dictionary_impl.h" // dd::Dictionary_impl
#include "sql/dd/impl/system_registry.h" // dd::System_views
#include "sql/dd/impl/utils.h" // dd::System_views
#include "sql/dd/properties.h" // dd::Properties
#include "sql/dd/types/abstract_table.h"
#include "sql/dd/types/column.h" // dd::Column
#include "sql/dd/types/schema.h"
#include "sql/dd/types/system_view.h"
#include "sql/dd/types/system_view_definition.h" // dd::System_view_definition
#include "sql/dd/types/view.h"
#include "sql/dd_sql_view.h" // update_referencing_views_metadata
#include "sql/handler.h"
#include "sql/item_create.h"
#include "sql/mdl.h"
#include "sql/mysqld.h" // opt_readonly
#include "sql/sql_class.h" // THD
#include "sql/sql_lex.h"
#include "sql/sql_plugin.h" // plugin_foreach
#include "sql/sql_plugin_ref.h"
#include "sql/sql_profile.h"
#include "sql/sql_show.h"
#include "sql/system_variables.h"
#include "sql/table.h"
#include "sql/thd_raii.h"
#include "sql/dd/dd_minor_upgrade.h"
namespace {
unsigned int UNKNOWN_PLUGIN_VERSION = -1;
const dd::String_type PLUGIN_VERSION_STRING("plugin_version");
const dd::String_type SERVER_I_S_TABLE_STRING("server_i_s_table");
} // namespace
/**
Check if DDSE (Data Dictionary Storage Engine) is in
readonly mode.
@param thd Thread
@param schema_name_abbrev Abbreviation of schema (I_S or P_S) for use
in warning message output
@returns false on success, otherwise true.
*/
bool check_if_server_ddse_readonly(THD *thd, const char *schema_name_abbrev) {
/*
We must check if the DDSE is started in a way that makes the DD
read only. For now, we only support InnoDB as SE for the DD. The call
to retrieve the handlerton for the DDSE should be replaced by a more
generic mechanism.
*/
handlerton *ddse = ha_resolve_by_legacy_type(thd, DB_TYPE_INNODB);
if (ddse->is_dict_readonly && ddse->is_dict_readonly()) {
LogErr(WARNING_LEVEL, ER_SKIP_UPDATING_METADATA_IN_SE_RO_MODE,
schema_name_abbrev);
return true;
}
return false;
}
namespace {
// Hold context during IS metadata update to DD.
class Update_context {
public:
Update_context(THD *thd, bool commit_gaurd)
: m_thd(thd),
m_saved_var_tx_read_only(thd->variables.transaction_read_only),
m_saved_tx_read_only(thd->tx_read_only),
m_autocommit_guard(commit_gaurd ? thd : nullptr),
m_mdl_handler(thd),
m_auto_releaser(thd->dd_client()),
m_schema_obj(nullptr),
m_plugin_names(nullptr) {
/*
Set tx_read_only to false to allow installing DD tables even
if the server is started with --transaction-read-only=true.
*/
m_thd->variables.transaction_read_only = false;
m_thd->tx_read_only = false;
if (m_mdl_handler.ensure_locked(INFORMATION_SCHEMA_NAME.str) ||
m_thd->dd_client()->acquire(INFORMATION_SCHEMA_NAME.str, &m_schema_obj))
m_schema_obj = nullptr;
DBUG_ASSERT(m_schema_obj);
}
~Update_context() {
// Restore thd state.
m_thd->variables.transaction_read_only = m_saved_var_tx_read_only;
m_thd->tx_read_only = m_saved_tx_read_only;
}
const dd::Schema *info_schema() { return m_schema_obj; }
void set_plugin_names(std::vector<dd::String_type> *names) {
m_plugin_names = names;
}
std::vector<dd::String_type> *plugin_names() { return m_plugin_names; }
private:
THD *m_thd;
bool m_saved_var_tx_read_only;
bool m_saved_tx_read_only;
Disable_autocommit_guard m_autocommit_guard;
dd::Schema_MDL_locker m_mdl_handler;
dd::cache::Dictionary_client::Auto_releaser m_auto_releaser;
// DD object for INFORMATION_SCHEMA.
const dd::Schema *m_schema_obj;
// List of plugins whose I_S tables are already present in DD.
std::vector<dd::String_type> *m_plugin_names;
};
/**
Holds context during I_S table referencing view's status/column metadata
update.
*/
class View_metadata_update_ctx {
public:
View_metadata_update_ctx(THD *thd, bool is_drop_tbl_op)
: m_thd(thd), m_saved_sql_command(thd->lex->sql_command) {
m_thd->lex->sql_command =
is_drop_tbl_op ? SQLCOM_UNINSTALL_PLUGIN : SQLCOM_INSTALL_PLUGIN;
}
~View_metadata_update_ctx() { m_thd->lex->sql_command = m_saved_sql_command; }
private:
// Thread Handle.
THD *m_thd;
// Saved SQL command.
enum_sql_command m_saved_sql_command;
};
/**
Store metadata from ST_SCHEMA_TABLE into DD tables.
Store option plugin_version=version, if it is not UNKNOWN_PLUGIN_VERSION,
otherwise store server_i_s_table=true.
@param thd Thread
@param ctx Update context.
@param schema_table Pointer to ST_SCHEMA_TABLE contain
metadata of IS table.
@param version Plugin version.
@returns false on success, else true.
*/
bool store_in_dd(THD *thd, Update_context *ctx, ST_SCHEMA_TABLE *schema_table,
unsigned int version) {
// Skip I_S tables that are hidden from users.
if (schema_table->hidden) return false;
std::unique_ptr<dd::View> view_obj(
ctx->info_schema()->create_system_view(thd));
// Set view properties
view_obj->set_client_collation_id(ctx->info_schema()->default_collation_id());
view_obj->set_connection_collation_id(
ctx->info_schema()->default_collation_id());
view_obj->set_name(schema_table->table_name);
dd::Properties *view_options = &view_obj->options();
if (version != UNKNOWN_PLUGIN_VERSION)
view_options->set(PLUGIN_VERSION_STRING, version);
else
view_options->set(SERVER_I_S_TABLE_STRING, true);
/*
Fill columns details
*/
ST_FIELD_INFO *fields_info = schema_table->fields_info;
const CHARSET_INFO *cs = get_charset(system_charset_info->number, MYF(0));
for (; fields_info->field_name; fields_info++) {
dd::Column *col_obj = view_obj->add_column();
col_obj->set_name(fields_info->field_name);
/*
The 5.7 create_schema_table() creates Item_empty_string() item for
MYSQL_TYPE_STRING. Item_empty_string->field_type() maps to
MYSQL_TYPE_VARCHAR. So, we map MYSQL_TYPE_STRING to
MYSQL_TYPE_VARCHAR when storing metadata into DD.
*/
enum_field_types ft = fields_info->field_type;
uint32 fl = fields_info->field_length;
if (fields_info->field_type == MYSQL_TYPE_STRING) {
ft = MYSQL_TYPE_VARCHAR;
}
col_obj->set_type(dd::get_new_field_type(ft));
col_obj->set_char_length(fields_info->field_length);
col_obj->set_nullable(fields_info->field_flags & MY_I_S_MAYBE_NULL);
col_obj->set_unsigned(fields_info->field_flags & MY_I_S_UNSIGNED);
col_obj->set_zerofill(false);
// Collation ID
col_obj->set_collation_id(system_charset_info->number);
col_obj->set_column_type_utf8(dd::get_sql_type_by_field_info(
thd, ft, fl, 0, col_obj->is_nullable(), col_obj->is_unsigned(), cs));
col_obj->set_default_value_utf8(dd::String_type(STRING_WITH_LEN("")));
}
/*
Acquire MDL on the view name, if not yet acquired.
In case of INSTALL PLUGIN, the lock would be already taken. We acquire
lock here during server restart and bootstrap.
*/
if (thd->mdl_context.owns_equal_or_stronger_lock(
MDL_key::TABLE, ctx->info_schema()->name().c_str(),
view_obj->name().c_str(), MDL_EXCLUSIVE) == false) {
MDL_request mdl_request;
MDL_REQUEST_INIT(&mdl_request, MDL_key::TABLE,
ctx->info_schema()->name().c_str(),
view_obj->name().c_str(), MDL_EXCLUSIVE, MDL_TRANSACTION);
if (thd->mdl_context.acquire_lock(&mdl_request,
thd->variables.lock_wait_timeout))
return true;
}
// Store the metadata into DD
if (thd->dd_client()->store(view_obj.get())) {
DBUG_ASSERT(thd->is_system_thread() || thd->killed || thd->is_error());
return (true);
}
return false;
}
/**
Helper method to store plugin IS table metadata into DD.
Skip storing, if the I_S name is already present in
Update_context plugin names.
@param thd Thread ID
@param plugin Reference to a plugin.
@param arg Pointer to Context for I_S update.
@param[out] plugin_exists Flag is set if plugin metadata already exists in
data-dictionary.
@return
false on success
true when fails to store the metadata.
*/
static bool store_plugin_metadata(THD *thd, plugin_ref plugin,
Update_context *ctx) {
DBUG_ASSERT(plugin && ctx);
// Store in DD tables.
st_plugin_int *pi = plugin_ref_to_int(plugin);
ST_SCHEMA_TABLE *schema_table = plugin_data<ST_SCHEMA_TABLE *>(plugin);
return store_in_dd(thd, ctx, schema_table, pi->plugin->version);
}
/**
Store plugin IS table metadata into DD.
Update column metadata of views referencing I_S plugin table.
Skip storing, if the I_S name is already present in
Update_context plugin names.
@param thd Thread ID
@param plugin Reference to a plugin.
@param arg Pointer to Context for I_S update.
@return
false on success
true when fails to store the metadata.
*/
bool store_plugin_and_referencing_views_metadata(THD *thd, plugin_ref plugin,
void *arg) {
st_plugin_int *pi = plugin_ref_to_int(plugin);
Update_context *ctx = static_cast<Update_context *>(arg);
// Stop if we already have IS metadata in DD.
if (ctx->plugin_names()) {
dd::String_type name(pi->name.str, pi->name.length);
if (std::find(ctx->plugin_names()->begin(), ctx->plugin_names()->end(),
name) != ctx->plugin_names()->end()) {
return false;
}
}
View_metadata_update_ctx vw_update_ctx(thd, false);
// Guard for uncommitted tables while updating views column metadata.
Uncommitted_tables_guard uncommitted_tables(thd);
return store_plugin_metadata(thd, plugin, ctx) ||
update_referencing_views_metadata(
thd, INFORMATION_SCHEMA_NAME.str,
(plugin_data<ST_SCHEMA_TABLE *>(plugin))->table_name, false,
&uncommitted_tables);
}
/**
Iterate through dynamic I_S plugins, and store I_S table
metadata into dictionary, during MySQL server startup. These
are plugins that are loaded using server command line options.
Does following,
- Remove I_S table metadata for plugins that are not loaded.
- Store I_S table metadata of plugins that are newly loaded.
@param thd Thread
@returns false on success, otherwise true.
*/
bool update_plugins_I_S_metadata(THD *thd) {
// Warn if we have DDSE in read only mode and continue server startup.
if (check_if_server_ddse_readonly(thd, INFORMATION_SCHEMA_NAME.str))
return false;
/*
Stage 1:
Remove I_S table metadata for plugins that are not loaded.
*/
/*
Create std::vector to hold 'plugin_name' of I_S tables that are
persistent in DD and if the plugin is loaded.
*/
Update_context ctx(thd, true);
std::vector<dd::String_type> plugin_names;
ctx.set_plugin_names(&plugin_names);
std::vector<const dd::View *> sch_views;
if (thd->dd_client()->fetch_schema_components(ctx.info_schema(), &sch_views))
return true;
bool error = false;
for (const dd::View *view : sch_views) {
// Skip if this is not a plugin I_S metadata.
const dd::Properties *view_options = &view->options();
if (!view_options->exists(PLUGIN_VERSION_STRING)) continue;
// Lookup if plugin is loaded during this server startup.
LEX_CSTRING plugin_name = {
view->name().c_str(), static_cast<unsigned int>(view->name().length())};
plugin_ref plugin = my_plugin_lock_by_name(thd, plugin_name,
MYSQL_INFORMATION_SCHEMA_PLUGIN);
if (plugin != nullptr) {
unsigned int plugin_version = 0;
st_plugin_int *plugin_int = plugin_ref_to_int(plugin);
view_options->get(PLUGIN_VERSION_STRING, &plugin_version);
// Testing to make sure we update plugins when version changes.
DBUG_EXECUTE_IF("test_i_s_metadata_version",
{ plugin_version = UNKNOWN_PLUGIN_VERSION; });
if (plugin_int->plugin->version == plugin_version &&
plugin_int->state == PLUGIN_IS_READY) {
plugin_names.push_back(view->name());
continue;
}
}
// Remove metadata from DD if version mismatch.
if (dd::info_schema::remove_I_S_view_metadata(thd, view->name())) break;
// Update status of referencing views.
{
View_metadata_update_ctx vw_update_ctx(thd, true);
// Guard for uncommitted tables while updating views column metadata.
Uncommitted_tables_guard uncommitted_tables(thd);
if (update_referencing_views_metadata(thd, INFORMATION_SCHEMA_NAME.str,
view->name().c_str(), false,
&uncommitted_tables))
break;
}
}
/*
Stage 2:
Store I_S table metadata of plugins that are newly loaded.
*/
error = error || plugin_foreach_with_mask(
thd, store_plugin_and_referencing_views_metadata,
MYSQL_INFORMATION_SCHEMA_PLUGIN, PLUGIN_IS_READY, &ctx);
return dd::end_transaction(thd, error);
}
/**
Does following during server restart.
- If I_S version is not changed, do nothing.
- Else, remove all I_S metadata that belongs to server.
- Store new server I_S metadata.
- Recreate I_S system views, which will update old I_S metadata
because we execute CREATE OR REPLACE VIEW.
@param thd Thread
@returns false on success, otherwise true.
*/
bool update_server_I_S_metadata(THD *thd) {
bool error = false;
dd::Dictionary_impl *d = dd::Dictionary_impl::instance();
// Stop if I_S version is same and no DD upgrade was done.
uint actual_version = d->get_actual_I_S_version(thd);
// Extra I_S version check
dd::Minor_upgrade_ctx *upgrade_ctx = dd::Minor_upgrade_ctx::instance();
uint extra_version = upgrade_ctx->get_actual_extra_I_S_version(thd);
// Testing to make sure we update plugins when version changes.
DBUG_EXECUTE_IF("test_i_s_metadata_version",
{ actual_version = UNKNOWN_PLUGIN_VERSION; });
if (d->get_target_I_S_version() == actual_version &&
upgrade_ctx->get_target_extra_I_S_version() == extra_version &&
!dd::bootstrap::DD_bootstrap_ctx::instance().dd_upgrade_done())
return false;
/*
Stop server restart if I_S version is changed and the server is
started with DDSE in read-only mode.
*/
if (check_if_server_ddse_readonly(thd, INFORMATION_SCHEMA_NAME.str))
return true;
Update_context ctx(thd, true);
const dd::Schema *sch_obj = ctx.info_schema();
if (sch_obj == nullptr) return true;
/*
Stage 1:
Remove all server I_S metadata from DD tables.
*/
std::vector<const dd::View *> sch_views;
if (thd->dd_client()->fetch_schema_components(sch_obj, &sch_views))
return true;
for (const dd::View *view : sch_views) {
// Skip if this is not a server I_S table.
const dd::Properties *view_options = &view->options();
if (!view_options->exists(PLUGIN_VERSION_STRING)) {
// Remove metadata from DD as I_S version is changed.
error = dd::info_schema::remove_I_S_view_metadata(thd, view->name());
if (error) break;
// Update status of views referencing a system view.
{
View_metadata_update_ctx vw_update_ctx(thd, true);
// Guard for uncommitted tables while updating views column metadata.
Uncommitted_tables_guard uncommitted_tables(thd);
error = update_referencing_views_metadata(
thd, INFORMATION_SCHEMA_NAME.str, view->name().c_str(), false,
&uncommitted_tables);
if (error) break;
}
}
}
/*
Stage 2:
1) Store server I_S tables
2) Recreate system view.
3) Update the target IS version in DD.
*/
error = error || dd::info_schema::store_server_I_S_metadata(thd) ||
dd::info_schema::create_system_views(thd);
return dd::end_transaction(thd, error);
}
} // namespace
namespace dd {
namespace info_schema {
/*
Create INFORMATION_SCHEMA system views.
*/
bool create_system_views(THD *thd) {
// Force use of utf8 charset.
const CHARSET_INFO *client_cs = thd->variables.character_set_client;
const CHARSET_INFO *cs = thd->variables.collation_connection;
const CHARSET_INFO *m_client_cs, *m_connection_cl;
resolve_charset("utf8", system_charset_info, &m_client_cs);
resolve_collation("utf8_general_ci", system_charset_info, &m_connection_cl);
thd->variables.character_set_client = m_client_cs;
thd->variables.collation_connection = m_connection_cl;
thd->update_charset();
// Iterate over system view definitions.
dd::System_views::Const_iterator it = dd::System_views::instance()->begin();
bool error = false;
for (; it != dd::System_views::instance()->end(); ++it) {
const dd::system_views::System_view_definition *view_def =
(*it)->entity()->view_definition();
// Build the CREATE VIEW DDL statement and execute it.
if (view_def == nullptr ||
dd::execute_query(thd, view_def->build_ddl_create_view())) {
error = true;
break;
}
}
// Store the target I_S version.
if (!error) {
dd::Dictionary_impl *d = dd::Dictionary_impl::instance();
error = d->set_I_S_version(thd, d->get_target_I_S_version());
if (!error) {
dd::Minor_upgrade_ctx *upgrade_ctx = dd::Minor_upgrade_ctx::instance();
error = upgrade_ctx->set_extra_I_S_version(
thd, upgrade_ctx->get_target_extra_I_S_version());
}
}
// Restore the original character set.
thd->variables.character_set_client = client_cs;
thd->variables.collation_connection = cs;
thd->update_charset();
return error;
}
/*
Store the server I_S table metadata into dictionary, once during MySQL
server bootstrap.
*/
bool store_server_I_S_metadata(THD *thd) {
bool error = false;
Update_context ctx(thd, false);
ST_SCHEMA_TABLE *schema_tables = get_schema_table(SCH_FIRST);
{
View_metadata_update_ctx vw_update_ctx(thd, false);
// Guard for uncommitted tables while updating views column metadata.
Uncommitted_tables_guard uncommitted_tables(thd);
for (; schema_tables->table_name && !error; schema_tables++) {
error = store_in_dd(thd, &ctx, schema_tables, UNKNOWN_PLUGIN_VERSION);
if (!error) {
// Update column metadata of views referencing I_S plugin table.
error = update_referencing_views_metadata(
thd, INFORMATION_SCHEMA_NAME.str, schema_tables->table_name, false,
&uncommitted_tables);
}
}
}
return dd::end_transaction(thd, error);
}
// Update server and plugin I_S table metadata on server restart.
bool update_I_S_metadata(THD *thd) {
return update_server_I_S_metadata(thd) || update_plugins_I_S_metadata(thd);
}
/*
Store dynamic I_S plugin table metadata into dictionary, during INSTALL
command execution.
*/
bool store_dynamic_plugin_I_S_metadata(THD *thd, st_plugin_int *plugin_int) {
plugin_ref plugin = plugin_int_to_ref(plugin_int);
Update_context ctx(thd, false);
DBUG_ASSERT(plugin_int->plugin->type == MYSQL_INFORMATION_SCHEMA_PLUGIN);
return store_plugin_metadata(thd, plugin, &ctx);
}
/*
Remove the given plugin I_S table metadata from dictionary table.
*/
bool remove_I_S_view_metadata(THD *thd, const dd::String_type &view_name) {
// Make sure you have lock on I_S schema.
Schema_MDL_locker mdl_locker(thd);
if (mdl_locker.ensure_locked(INFORMATION_SCHEMA_NAME.str)) return true;
// Acquire exclusive lock on it before dropping.
MDL_request mdl_request;
MDL_REQUEST_INIT(&mdl_request, MDL_key::TABLE, INFORMATION_SCHEMA_NAME.str,
view_name.c_str(), MDL_EXCLUSIVE, MDL_TRANSACTION);
if (thd->mdl_context.acquire_lock(&mdl_request,
thd->variables.lock_wait_timeout))
return (true);
// Acquire the object.
const dd::Abstract_table *at = nullptr;
if (thd->dd_client()->acquire(INFORMATION_SCHEMA_NAME.str, view_name.c_str(),
&at))
return (true);
DBUG_ASSERT(at->type() == dd::enum_table_type::SYSTEM_VIEW);
// Remove view from DD tables.
Disable_gtid_state_update_guard disabler(thd);
if (thd->dd_client()->drop(at)) {
DBUG_ASSERT(thd->is_system_thread() || thd->killed || thd->is_error());
return (true);
}
return (false);
}
bool initialize(THD *thd) {
/*
Set tx_read_only to false to allow installing system views even
if the server is started with --transaction-read-only=true.
*/
thd->variables.transaction_read_only = false;
thd->tx_read_only = false;
Disable_autocommit_guard autocommit_guard(thd);
Dictionary_impl *d = dd::Dictionary_impl::instance();
DBUG_ASSERT(d);
if (create_system_views(thd) || store_server_I_S_metadata(thd)) return true;
LogErr(INFORMATION_LEVEL, ER_CREATED_SYSTEM_WITH_VERSION,
(int)d->get_target_dd_version());
return false;
}
/*
Get create view definition for the given I_S system view.
*/
bool get_I_S_view_definition(const dd::String_type &schema_name,
const dd::String_type &view_name,
dd::String_type *definition) {
definition->clear();
const dd::system_views::System_view *sys_view =
dd::System_views::instance()->find(schema_name.c_str(),
view_name.c_str());
if (sys_view == nullptr) return true;
const dd::system_views::System_view_definition *view_def =
sys_view->view_definition();
if (view_def == nullptr) return true;
*definition = view_def->build_ddl_create_view();
return (false);
}
} // namespace info_schema
} // namespace dd
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