path: root/table_sizes.cc

/*
  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 <mysql/plugin.h>
#include <boost/optional/optional.hpp>

#include "sql/mysqld.h"
#include "sql/sql_base.h"
#include "sql/sql_class.h"    // THD
#include "sql/sql_table.h"    // filename_to_tablename
#include "sql/strfunc.h"      // casedn
#include "sql/sql_parse.h"    // sql_command_flags
#include "sql/sql_lex.h"      // LEX
#include "sql/item_func.h"    // Item_Func
#include "sql/item_cmpfunc.h" // Item_cond
#include "sql/dd/cache/dictionary_client.h"  // dd::cache::Dictionary_client
#include "sql/dd/dd_schema.h"     // dd::Schema_MDL_locker
#include "sql/dd/string_type.h"   // dd::String_type
#include "sql/dd/sdi_file.h"      // dd::sdi_file
#include "sql/auth/auth_acls.h"   // *_ACLS
#include "sql/auth/auth_common.h" // check_grant_db
#include "mf_wcomp.h" // wild_compare,wild_one,wild_many
#include "my_dir.h"   // MY_DIR

// InnoDB FTS
/** For storing table info when checking for orphaned tables. */
struct fts_aux_table_t
{
  /** Parent table id */
  uint64_t parent_id;

  /** Table FT index id */
  uint64_t index_id;
};

/** Check if a table is an FTS auxiliary table name.
@param[out]	table	FTS table info
@param[in]	name	Table name
@param[in]	len	Length of table name
@return true if the name matches an auxiliary table name pattern */
bool fts_is_aux_table_name(fts_aux_table_t *table, const char *name,
                           int len)
{
  /** FTS auxiliary table prefix that are common to all FT indexes.*/
  const char *FTS_PREFIX = "fts_";
  const char *FTS_PREFIX_5_7 = "FTS_";

  /** FTS auxiliary table suffixes that are common to all FT indexes. */
  const char *fts_common_tables[] = {"being_deleted", "being_deleted_cache",
                                     "config",        "deleted",
                                     "deleted_cache", NULL};
  const char *fts_common_tables_5_7[] = {"BEING_DELETED", "BEING_DELETED_CACHE",
                                         "CONFIG",        "DELETED",
                                         "DELETED_CACHE", NULL};

  /** FTS auxiliary INDEX split intervals. */
  const char *fts_index_selector[] = {"index_1", "index_2", "index_3", "index_4",
                                      "index_5", "index_6", NULL};
  const char *fts_index_selector_5_7[] = {"INDEX_1", "INDEX_2", "INDEX_3", "INDEX_4",
                                          "INDEX_5", "INDEX_6", NULL};

  const char *ptr = name;
  const char *end = name + len;

  /* All auxiliary tables are prefixed with "FTS_" and the name
  length will be at the very least greater than 20 bytes. */
  if (ptr != NULL && len > 20 &&
      (strncmp(ptr, FTS_PREFIX, 4) == 0 ||
       strncmp(ptr, FTS_PREFIX_5_7, 4) == 0))
  {
    /* Skip the prefix. */
    ptr += 4;
    len -= 4;

    /* Try and read the table id. */
    if (sscanf(ptr, "%016" PRIx64, &table->parent_id) != 1)
      return false;

    /* Skip the table id. */
    ptr = static_cast<const char *>(memchr(ptr, '_', len));
    if (ptr == NULL)
      return false;

    /* Skip the underscore. */
    ++ptr;
    len = end - ptr;

    /* First search the common table suffix array. */
    for (int i = 0; fts_common_tables[i] != NULL; ++i) {
      if (strncmp(ptr, fts_common_tables[i], len) == 0 ||
          strncmp(ptr, fts_common_tables_5_7[i], len) == 0) {
        return true;
      }
    }

    /* Could be obsolete common tables. */
    if (native_strncasecmp(ptr, "ADDED", len) == 0 ||
        native_strncasecmp(ptr, "STOPWORDS", len) == 0) {
      return true;
    }

    /* Try and read the index id. */
    if (sscanf(ptr, "%016" PRIx64, &table->index_id) != 1)
      return false;

    /* Skip the index id. */
    ptr = static_cast<const char *>(memchr(ptr, '_', len));

   if (ptr == NULL)
      return false;

    /* Skip the underscore. */
    ++ptr;
    len = end - ptr;

    /* Search the FT index specific array. */
    for (int i = 0; fts_index_selector[i] != NULL; ++i) {
      if (strncmp(ptr, fts_index_selector[i], len) == 0 ||
          strncmp(ptr, fts_index_selector_5_7[i], len) == 0) {
        return true;
      }
    }

    /* Other FT index specific table(s). */
    if (native_strncasecmp(ptr, "DOC_ID", len) == 0)
      return true;
  }

  return false;
}

/*----------------------------------------------------------------------------*/

/**
  Condition pushdown used for INFORMATION_SCHEMA / SHOW queries.
  This structure is to implement an optimization when
  accessing data dictionary data in the INFORMATION_SCHEMA
  or SHOW commands.
  When the query contain a TABLE_SCHEMA or TABLE_NAME clause,
  narrow the search for data based on the constraints given.
*/
struct LOOKUP_FIELD_VALUES {
  /**
    Value of a TABLE_SCHEMA clause.
    Note that this value length may exceed @c NAME_LEN.
  */
  boost::optional<dd::String_type> db_value;
  /**
    Value of a TABLE_NAME clause.
    Note that this value length may exceed @c NAME_LEN.
  */
  boost::optional<dd::String_type> table_value;
};

/**
  @brief    Get lookup value from the part of 'WHERE' condition

  @details This function gets lookup value from
           the part of 'WHERE' condition if it's possible and
           fill appropriate lookup_field_vals struct field
           with this value.

  @param[in]      thd                   thread handler
  @param[in]      item_func             part of WHERE condition
  @param[in]      table                 I_S table
  @param[in, out] lookup_field_vals     Struct which holds lookup values

  @return
    0             success
    1             error, there can be no matching records for the condition
*/

static bool get_lookup_value(Item_func *item_func, Table_ref *table,
    LOOKUP_FIELD_VALUES *lookup_field_vals)
{
  ST_SCHEMA_TABLE *schema_table = table->schema_table;
  ST_FIELD_INFO *field_info = schema_table->fields_info;

  if (item_func->functype() == Item_func::EQ_FUNC ||
      item_func->functype() == Item_func::EQUAL_FUNC) {
    int idx_field, idx_val;
    char tmp[MAX_FIELD_WIDTH];
    String *tmp_str, str_buff(tmp, sizeof(tmp), system_charset_info);
    Item_field *item_field;
    CHARSET_INFO *cs = system_charset_info;

    if (item_func->arguments()[0]->type() == Item::FIELD_ITEM &&
        item_func->arguments()[1]->const_item()) {
      idx_field = 0;
      idx_val = 1;
    } else if (item_func->arguments()[1]->type() == Item::FIELD_ITEM &&
               item_func->arguments()[0]->const_item()) {
      idx_field = 1;
      idx_val = 0;
    } else
      return 0;

    item_field = (Item_field *)item_func->arguments()[idx_field];
    if (table->table != item_field->field->table) return 0;
    tmp_str = item_func->arguments()[idx_val]->val_str(&str_buff);

    /* impossible value */
    if (!tmp_str) return 1;

    /* Lookup value is database name */
    if (!cs->coll->strnncollsp(cs, (const uchar *)field_info[0].field_name,
                               strlen(field_info[0].field_name),
                               (const uchar *)item_field->field_name,
                               strlen(item_field->field_name))) {
      lookup_field_vals->db_value.emplace(tmp_str->ptr(), tmp_str->length());
    }
    /* Lookup value is table name */
    else if (!cs->coll->strnncollsp(cs, (const uchar *)field_info[1].field_name,
                                    strlen(field_info[1].field_name),
                                    (const uchar *)item_field->field_name,
                                    strlen(item_field->field_name))) {
      lookup_field_vals->table_value.emplace(tmp_str->ptr(), tmp_str->length());
    }
  }
  return 0;
}

/**
  @brief    Calculates lookup values from 'WHERE' condition

  @details This function calculates lookup value(database name, table name)
           from 'WHERE' condition if it's possible and
           fill lookup_field_vals struct fields with these values.

  @param[in]      thd                   thread handler
  @param[in]      cond                  WHERE condition
  @param[in]      table                 I_S table
  @param[in, out] lookup_field_vals     Struct which holds lookup values

  @return
    0             success
    1             error, there can be no matching records for the condition
*/

static bool calc_lookup_values_from_cond(Item *cond,
    Table_ref *table, LOOKUP_FIELD_VALUES *lookup_field_vals)
{
  if (!cond) return 0;

  if (cond->type() == Item::COND_ITEM) {
    if (((Item_cond *)cond)->functype() == Item_func::COND_AND_FUNC) {
      List_iterator<Item> li(*((Item_cond *)cond)->argument_list());
      Item *item;
      while ((item = li++)) {
        if (item->type() == Item::FUNC_ITEM) {
          if (get_lookup_value((Item_func *)item, table, lookup_field_vals))
            return 1;
        } else {
          if (calc_lookup_values_from_cond(item, table, lookup_field_vals))
            return 1;
        }
      }
    }
    return 0;
  } else if (cond->type() == Item::FUNC_ITEM &&
             get_lookup_value((Item_func *)cond, table, lookup_field_vals))
    return 1;
  return 0;
}

/**
  @brief   Calculate lookup values(database name, table name)

  @details This function calculates lookup values(database name, table name)
           from 'WHERE' condition and fill lookup_field_vals struct field
           with these values.

  @param[in]      cond                WHERE condition
  @param[in]      tables              I_S table
  @param[in, out] lookup_field_vals   Struct which holds lookup values

  @return
    0             success
    1             error, there can be no matching records for the condition
*/

static bool get_lookup_field_values(Item *cond, Table_ref *tables,
    LOOKUP_FIELD_VALUES *lookup_field_vals)
{
  bool rc = calc_lookup_values_from_cond(cond, tables, lookup_field_vals);

  if (lower_case_table_names && !rc) {
    /*
      We can safely do in-place upgrades here since all of the above cases
      are allocating a new memory buffer for these strings.
    */
    if (lookup_field_vals->db_value && !lookup_field_vals->db_value->empty())
      casedn(system_charset_info, *lookup_field_vals->db_value);
    if (lookup_field_vals->table_value && !lookup_field_vals->table_value->empty())
      casedn(system_charset_info, *lookup_field_vals->table_value);
  }

  return rc;
}

/*----------------------------------------------------------------------------*/

static bool is_special_db(const dd::String_type &db_name)
{
  /* I_S does not exist and we hide P_S */
  return is_infoschema_db(db_name.c_str(), db_name.size())
    || is_perfschema_db(db_name.c_str(), db_name.size());
}

/**
  Return either single or all schemas

  @param[in]  thd                thread handler
  @param[out] db_names           list of schemas
  @param[in]  lookup_field_vals  Struct which holds lookup values

  @return true  if error, false otherwise
*/
static int make_db_list(THD *thd, std::vector<dd::String_type> *db_names,
    LOOKUP_FIELD_VALUES *lookup_field_vals)
{
  /*
    If we have db lookup value we just add it to list and
    exit from the function.
    We don't do this for database names longer than the maximum
    path length.
  */
  if (lookup_field_vals->db_value
      && lookup_field_vals->db_value->length() <= NAME_LEN)
  {
    const dd::String_type &db_name = lookup_field_vals->db_value.get();
    if (!is_special_db(db_name))
      db_names->push_back(db_name);
    return 0;
  }

  dd::cache::Dictionary_client::Auto_releaser releaser(thd->dd_client());
  std::vector<const dd::Schema *> schemas;
  if (thd->dd_client()->fetch_global_components(&schemas))
    return 1;

  for (const dd::Schema *schema_obj : schemas)
  {
    const dd::String_type &db_name = schema_obj->name();
    if (is_special_db(db_name))
      continue;
    db_names->push_back(db_name);
  }
  return 0;
}

/*----------------------------------------------------------------------------*/

/**
   Find files in a given directory.

   @param thd     thread handler
   @param tables  put found files in this list
   @param db_name   filter for found files
   @param wild    filter for found files

   @return true  if error, false otherwise
*/
typedef std::map<dd::String_type, size_t> Table_sizes_map;
bool find_tables(THD *thd, Table_sizes_map &tables,
    Table_ref &db_data, boost::optional<dd::String_type> &wild)
{
  MY_DIR *dirp;
  DBUG_ENTER("find_files");

  char path[FN_REFLEN + 1];
  build_table_filename(path, sizeof(path) - 1, db_data.db, "", "", 0);

  if (!(dirp = my_dir(path, MYF(MY_WANT_STAT))))
  {
    if (my_errno() == ENOENT)
      my_error(ER_BAD_DB_ERROR, MYF(0), db_data.db);
    else
    {
      char errbuf[MYSYS_STRERROR_SIZE];
      my_error(ER_CANT_READ_DIR, MYF(0), path,
          my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno()));
    }
    return true;
  }

  char uname[NAME_LEN + 1]; /* Unencoded name */
  dd::String_type fts_schema_name, fts_table_name; /* FTS lookup */
  std::map<dd::Object_id, dd::String_type> fts_cache;
  tables.clear();
  for (uint i = 0; i < dirp->number_off_files; i++)
  {
    FILEINFO *file = dirp->dir_entry + i;
    /* skip '.', '..' and temp files. */
    if ((file->name[0] == '.' &&
        (!file->name[1] || (file->name[1] == '.' && !file->name[2])))
        || is_prefix(file->name, tmp_file_prefix))
      continue;

    char *ext;
    if ((ext = strrchr(file->name, '.')))
    {
      // sdi files are small and their name is truncated
      // lookup by id is possible but not worth the effort
      if (!strcmp(ext, dd::sdi_file::EXT.c_str()))
        continue;
      *ext = 0;
      ++ext;
    }

    size_t file_name_len;
    fts_aux_table_t fts_table;
    if (ext && !strcmp(ext, "ibd")
        && fts_is_aux_table_name(&fts_table, file->name, strlen(file->name)))
    {
      auto entry = fts_cache.find(fts_table.parent_id);
      if (entry != fts_cache.end())
        fts_table_name = entry->second;
      else if (thd->dd_client()->get_table_name_by_se_private_id("InnoDB",
            fts_table.parent_id, &fts_schema_name, &fts_table_name))
        continue;

      file_name_len = (my_stpnmov(uname, fts_table_name.c_str(), sizeof(uname)) - uname);
    }
    else
      file_name_len = filename_to_tablename(file->name, uname, sizeof(uname));

    auto table_data = tables.find(uname);
    if (table_data != tables.end())
    {
      table_data->second += file->mystat->st_size;
      continue;
    }

    if (wild)
    {
      if (lower_case_table_names)
      {
        if (my_wildcmp(files_charset_info,
              uname, uname + file_name_len,
              wild->c_str(), wild->c_str() + wild->length(),
              wild_prefix, wild_one, wild_many))
          continue;
      }
      else if (wild_compare(uname, file_name_len, wild->c_str(), wild->length(), 0))
        continue;
    }

    /*
      Check_grant will grant access if there is any column privileges on
      all of the tables thanks to the fourth parameter (bool show_table).
    */
    db_data.table_name = uname;
    db_data.table_name_length = file_name_len;
    if (check_grant(thd, SELECT_ACL, &db_data, true, 1, true))
      continue;

    tables.emplace(uname, file->mystat->st_size);
  }

  DBUG_PRINT("info", ("found: %ld files", tables.size()));
  my_dirend(dirp);

  return false;
}

static bool make_table_list(THD *thd, Table_sizes_map &table_names,
    LOOKUP_FIELD_VALUES *lookup_field_vals, Table_ref &db_data)
{
  const dd::Schema *sch_obj = NULL;
  if (thd->dd_client()->acquire(db_data.db, &sch_obj) || !sch_obj)
    return 1;

  return find_tables(thd, table_names, db_data, lookup_field_vals->table_value);
}

/*----------------------------------------------------------------------------*/

static ST_FIELD_INFO fields_info[] =
{
  {"TABLE_SCHEMA", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0, 0},
  {"TABLE_NAME", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, "Name", 0},
  {"TABLE_SIZE", MY_INT64_NUM_DECIMAL_DIGITS, MYSQL_TYPE_LONGLONG, 0,
    MY_I_S_UNSIGNED, "Table_size", 0},
  {0, 0, MYSQL_TYPE_STRING, 0, 0, 0, 0}
};

static int fill_table(THD *thd, Table_ref *tables, Item *cond)
{
  TABLE *table = tables->table;
  LOOKUP_FIELD_VALUES lookup_field_vals;
  std::vector<dd::String_type> db_names;

  DBUG_ENTER("fill_table");

  if (get_lookup_field_values(cond, tables, &lookup_field_vals))
    return 0;

#define STR_OR_NIL(S) ((S) ? (S->c_str()) : "<nil>")
  DBUG_PRINT("INDEX VALUES", ("db_name='%s', table_name='%s'",
        STR_OR_NIL(lookup_field_vals.db_value),
        STR_OR_NIL(lookup_field_vals.table_value)));

  /* EXPLAIN SELECT */
  if (thd->lex->is_explain())
    return 0;

  if (make_db_list(thd, &db_names, &lookup_field_vals))
    return 1;

  for (auto &db_name : db_names)
  {
    Table_ref db_data;
    memset(reinterpret_cast<char *>(&db_data), 0, sizeof(db_data));
    db_data.db = db_name.c_str();
    db_data.db_length = db_name.length();
    db_data.grant.privilege = 0;

    // Get user's global and db-level privileges.
    if (check_access(thd, SELECT_ACL, db_data.db, &db_data.grant.privilege, NULL, false, true))
      continue;

    // Now check, if user has access on global level or to any of database/
    // table/column/routine.
    if (!(db_data.grant.privilege & DB_OP_ACLS) && check_grant_db(thd, db_data.db))
      continue;

    // We must make sure the schema is released and unlocked in the right
    // order. Fail if we are unable to get a meta data lock on the schema
    // name.
    dd::Schema_MDL_locker mdl_handler(thd);
    if (mdl_handler.ensure_locked(db_data.db))
      return 1;

    dd::cache::Dictionary_client::Auto_releaser releaser(thd->dd_client());
    Table_sizes_map tables_data;
    int res = make_table_list(thd, tables_data, &lookup_field_vals, db_data);
    if (res)
      continue;

    for (auto &table_data : tables_data)
    {
      table->field[0]->store(db_data.db, db_data.db_length,
          system_charset_info);
      table->field[1]->store(table_data.first.c_str(), table_data.first.size(),
          system_charset_info);
      table->field[2]->store(table_data.second, true);
      if (schema_table_store_record(thd, table))
        return 1;
    }
  }

  return 0;
}

static int init(void *ptr)
{
  ST_SCHEMA_TABLE *schema_table = (ST_SCHEMA_TABLE*)ptr;

  schema_table->fields_info = fields_info;
  schema_table->fill_table = fill_table;
  return 0;
}

static struct st_mysql_information_schema info =
{ MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };

mysql_declare_plugin(table_sizes)
{
  MYSQL_INFORMATION_SCHEMA_PLUGIN,
  &info,                                 /* type-specific descriptor */
  "TABLE_SIZES",                         /* table name */
  "Manuel Mausz",                        /* author */
  "Fast INFORMATION_SCHEMA table sizes", /* description */
  PLUGIN_LICENSE_GPL,                    /* license type */
  init,                                  /* init function */
  NULL,
  NULL,
  0x0800,                                /* version = 8.0 */
  NULL,                                  /* no status variables */
  NULL,                                  /* no system variables */
  NULL,                                  /* no reserved information */
  0                                      /* no flags */
}
mysql_declare_plugin_end;