src/database-sqlite3.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 /*
  21 SQLite format specification:
  22         blocks:
  23                 (PK) INT id
  24                 BLOB data
  25 */
  26
  27
  28 #include "database-sqlite3.h"
  29
  30 #include "log.h"
  31 #include "filesys.h"
  32 #include "exceptions.h"
  33 #include "settings.h"
  34 #include "porting.h"
  35 #include "util/string.h"
  36
  37 #include <cassert>
  38
  39 // When to print messages when the database is being held locked by another process
  40 // Note: I've seen occasional delays of over 250ms while running minetestmapper.
  41 #define BUSY_INFO_TRESHOLD      100     // Print first informational message after 100ms.
  42 #define BUSY_WARNING_TRESHOLD   250     // Print warning message after 250ms. Lag is increased.
  43 #define BUSY_ERROR_TRESHOLD     1000    // Print error message after 1000ms. Significant lag.
  44 #define BUSY_FATAL_TRESHOLD     3000    // Allow SQLITE_BUSY to be returned, which will cause a minetest crash.
  45 #define BUSY_ERROR_INTERVAL     10000   // Safety net: report again every 10 seconds
  46
  47
  48 #define SQLRES(s, r, m) \
  49         if ((s) != (r)) { \
  50                 throw DatabaseException(std::string(m) + ": " +\
  51                                 sqlite3_errmsg(m_database)); \
  52         }
  53 #define SQLOK(s, m) SQLRES(s, SQLITE_OK, m)
  54
  55 #define PREPARE_STATEMENT(name, query) \
  56         SQLOK(sqlite3_prepare_v2(m_database, query, -1, &m_stmt_##name, NULL),\
  57                 "Failed to prepare query '" query "'")
  58
  59 #define SQLOK_ERRSTREAM(s, m)                           \
  60         if ((s) != SQLITE_OK) {                             \
  61                 errorstream << (m) << ": "                      \
  62                         << sqlite3_errmsg(m_database) << std::endl; \
  63         }
  64
  65 #define FINALIZE_STATEMENT(statement) SQLOK_ERRSTREAM(sqlite3_finalize(statement), \
  66         "Failed to finalize " #statement)
  67
  68 int Database_SQLite3::busyHandler(void *data, int count)
  69 {
  70         s64 &first_time = reinterpret_cast<s64 *>(data)[0];
  71         s64 &prev_time = reinterpret_cast<s64 *>(data)[1];
  72         s64 cur_time = getTimeMs();
  73
  74         if (count == 0) {
  75                 first_time = cur_time;
  76                 prev_time = first_time;
  77         } else {
  78                 while (cur_time < prev_time)
  79                         cur_time += s64(1)<<32;
  80         }
  81
  82         if (cur_time - first_time < BUSY_INFO_TRESHOLD) {
  83                 ; // do nothing
  84         } else if (cur_time - first_time >= BUSY_INFO_TRESHOLD &&
  85                         prev_time - first_time < BUSY_INFO_TRESHOLD) {
  86                 infostream << "SQLite3 database has been locked for "
  87                         << cur_time - first_time << " ms." << std::endl;
  88         } else if (cur_time - first_time >= BUSY_WARNING_TRESHOLD &&
  89                         prev_time - first_time < BUSY_WARNING_TRESHOLD) {
  90                 warningstream << "SQLite3 database has been locked for "
  91                         << cur_time - first_time << " ms." << std::endl;
  92         } else if (cur_time - first_time >= BUSY_ERROR_TRESHOLD &&
  93                         prev_time - first_time < BUSY_ERROR_TRESHOLD) {
  94                 errorstream << "SQLite3 database has been locked for "
  95                         << cur_time - first_time << " ms; this causes lag." << std::endl;
  96         } else if (cur_time - first_time >= BUSY_FATAL_TRESHOLD &&
  97                         prev_time - first_time < BUSY_FATAL_TRESHOLD) {
  98                 errorstream << "SQLite3 database has been locked for "
  99                         << cur_time - first_time << " ms - giving up!" << std::endl;
 100         } else if ((cur_time - first_time) / BUSY_ERROR_INTERVAL !=
 101                         (prev_time - first_time) / BUSY_ERROR_INTERVAL) {
 102                 // Safety net: keep reporting every BUSY_ERROR_INTERVAL
 103                 errorstream << "SQLite3 database has been locked for "
 104                         << (cur_time - first_time) / 1000 << " seconds!" << std::endl;
 105         }
 106
 107         prev_time = cur_time;
 108
 109         // Make sqlite transaction fail if delay exceeds BUSY_FATAL_TRESHOLD
 110         return cur_time - first_time < BUSY_FATAL_TRESHOLD;
 111 }
 112
 113
 114 Database_SQLite3::Database_SQLite3(const std::string &savedir) :
 115         m_initialized(false),
 116         m_savedir(savedir),
 117         m_database(NULL),
 118         m_stmt_read(NULL),
 119         m_stmt_write(NULL),
 120         m_stmt_list(NULL),
 121         m_stmt_delete(NULL),
 122         m_stmt_begin(NULL),
 123         m_stmt_end(NULL)
 124 {
 125 }
 126
 127 void Database_SQLite3::beginSave() {
 128         verifyDatabase();
 129         SQLRES(sqlite3_step(m_stmt_begin), SQLITE_DONE,
 130                 "Failed to start SQLite3 transaction");
 131         sqlite3_reset(m_stmt_begin);
 132 }
 133
 134 void Database_SQLite3::endSave() {
 135         verifyDatabase();
 136         SQLRES(sqlite3_step(m_stmt_end), SQLITE_DONE,
 137                 "Failed to commit SQLite3 transaction");
 138         sqlite3_reset(m_stmt_end);
 139 }
 140
 141 void Database_SQLite3::openDatabase()
 142 {
 143         if (m_database) return;
 144
 145         std::string dbp = m_savedir + DIR_DELIM + "map.sqlite";
 146
 147         // Open the database connection
 148
 149         if (!fs::CreateAllDirs(m_savedir)) {
 150                 infostream << "Database_SQLite3: Failed to create directory \""
 151                         << m_savedir << "\"" << std::endl;
 152                 throw FileNotGoodException("Failed to create database "
 153                                 "save directory");
 154         }
 155
 156         bool needs_create = !fs::PathExists(dbp);
 157
 158         SQLOK(sqlite3_open_v2(dbp.c_str(), &m_database,
 159                         SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL),
 160                 std::string("Failed to open SQLite3 database file ") + dbp);
 161
 162         SQLOK(sqlite3_busy_handler(m_database, Database_SQLite3::busyHandler,
 163                 m_busy_handler_data), "Failed to set SQLite3 busy handler");
 164
 165         if (needs_create) {
 166                 createDatabase();
 167         }
 168
 169         std::string query_str = std::string("PRAGMA synchronous = ")
 170                          + itos(g_settings->getU16("sqlite_synchronous"));
 171         SQLOK(sqlite3_exec(m_database, query_str.c_str(), NULL, NULL, NULL),
 172                 "Failed to modify sqlite3 synchronous mode");
 173 }
 174
 175 void Database_SQLite3::verifyDatabase()
 176 {
 177         if (m_initialized) return;
 178
 179         openDatabase();
 180
 181         PREPARE_STATEMENT(begin, "BEGIN");
 182         PREPARE_STATEMENT(end, "COMMIT");
 183         PREPARE_STATEMENT(read, "SELECT `data` FROM `blocks` WHERE `pos` = ? LIMIT 1");
 184 #ifdef __ANDROID__
 185         PREPARE_STATEMENT(write,  "INSERT INTO `blocks` (`pos`, `data`) VALUES (?, ?)");
 186 #else
 187         PREPARE_STATEMENT(write, "REPLACE INTO `blocks` (`pos`, `data`) VALUES (?, ?)");
 188 #endif
 189         PREPARE_STATEMENT(delete, "DELETE FROM `blocks` WHERE `pos` = ?");
 190         PREPARE_STATEMENT(list, "SELECT `pos` FROM `blocks`");
 191
 192         m_initialized = true;
 193
 194         verbosestream << "ServerMap: SQLite3 database opened." << std::endl;
 195 }
 196
 197 inline void Database_SQLite3::bindPos(sqlite3_stmt *stmt, const v3s16 &pos, int index)
 198 {
 199         SQLOK(sqlite3_bind_int64(stmt, index, getBlockAsInteger(pos)),
 200                 "Internal error: failed to bind query at " __FILE__ ":" TOSTRING(__LINE__));
 201 }
 202
 203 bool Database_SQLite3::deleteBlock(const v3s16 &pos)
 204 {
 205         verifyDatabase();
 206
 207         bindPos(m_stmt_delete, pos);
 208
 209         bool good = sqlite3_step(m_stmt_delete) == SQLITE_DONE;
 210         sqlite3_reset(m_stmt_delete);
 211
 212         if (!good) {
 213                 warningstream << "deleteBlock: Block failed to delete "
 214                         << PP(pos) << ": " << sqlite3_errmsg(m_database) << std::endl;
 215         }
 216         return good;
 217 }
 218
 219 bool Database_SQLite3::saveBlock(const v3s16 &pos, const std::string &data)
 220 {
 221         verifyDatabase();
 222
 223 #ifdef __ANDROID__
 224         /**
 225          * Note: For some unknown reason SQLite3 fails to REPLACE blocks on Android,
 226          * deleting them and then inserting works.
 227          */
 228         bindPos(m_stmt_read, pos);
 229
 230         if (sqlite3_step(m_stmt_read) == SQLITE_ROW) {
 231                 deleteBlock(pos);
 232         }
 233         sqlite3_reset(m_stmt_read);
 234 #endif
 235
 236         bindPos(m_stmt_write, pos);
 237         SQLOK(sqlite3_bind_blob(m_stmt_write, 2, data.data(), data.size(), NULL),
 238                 "Internal error: failed to bind query at " __FILE__ ":" TOSTRING(__LINE__));
 239
 240         SQLRES(sqlite3_step(m_stmt_write), SQLITE_DONE, "Failed to save block")
 241         sqlite3_reset(m_stmt_write);
 242
 243         return true;
 244 }
 245
 246 void Database_SQLite3::loadBlock(const v3s16 &pos, std::string *block)
 247 {
 248         verifyDatabase();
 249
 250         bindPos(m_stmt_read, pos);
 251
 252         if (sqlite3_step(m_stmt_read) != SQLITE_ROW) {
 253                 sqlite3_reset(m_stmt_read);
 254                 return;
 255         }
 256
 257         const char *data = (const char *) sqlite3_column_blob(m_stmt_read, 0);
 258         size_t len = sqlite3_column_bytes(m_stmt_read, 0);
 259
 260         *block = (data) ? std::string(data, len) : "";
 261
 262         sqlite3_step(m_stmt_read);
 263         // We should never get more than 1 row, so ok to reset
 264         sqlite3_reset(m_stmt_read);
 265 }
 266
 267 void Database_SQLite3::createDatabase()
 268 {
 269         assert(m_database); // Pre-condition
 270         SQLOK(sqlite3_exec(m_database,
 271                 "CREATE TABLE IF NOT EXISTS `blocks` (\n"
 272                 "       `pos` INT PRIMARY KEY,\n"
 273                 "       `data` BLOB\n"
 274                 ");\n",
 275                 NULL, NULL, NULL),
 276                 "Failed to create database table");
 277 }
 278
 279 void Database_SQLite3::listAllLoadableBlocks(std::vector<v3s16> &dst)
 280 {
 281         verifyDatabase();
 282
 283         while (sqlite3_step(m_stmt_list) == SQLITE_ROW) {
 284                 dst.push_back(getIntegerAsBlock(sqlite3_column_int64(m_stmt_list, 0)));
 285         }
 286         sqlite3_reset(m_stmt_list);
 287 }
 288
 289 Database_SQLite3::~Database_SQLite3()
 290 {
 291         FINALIZE_STATEMENT(m_stmt_read)
 292         FINALIZE_STATEMENT(m_stmt_write)
 293         FINALIZE_STATEMENT(m_stmt_list)
 294         FINALIZE_STATEMENT(m_stmt_begin)
 295         FINALIZE_STATEMENT(m_stmt_end)
 296         FINALIZE_STATEMENT(m_stmt_delete)
 297
 298         SQLOK_ERRSTREAM(sqlite3_close(m_database), "Failed to close database");
 299 }
 300