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 FileNotGoodException(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 FINALIZE_STATEMENT(statement) \
  60         SQLOK(sqlite3_finalize(statement), "Failed to finalize " #statement)
  61
  62 int Database_SQLite3::busyHandler(void *data, int count)
  63 {
  64         s64 &first_time = reinterpret_cast<s64 *>(data)[0];
  65         s64 &prev_time = reinterpret_cast<s64 *>(data)[1];
  66         s64 cur_time = getTimeMs();
  67
  68         if (count == 0) {
  69                 first_time = cur_time;
  70                 prev_time = first_time;
  71         } else {
  72                 while (cur_time < prev_time)
  73                         cur_time += s64(1)<<32;
  74         }
  75
  76         if (cur_time - first_time < BUSY_INFO_TRESHOLD) {
  77                 ; // do nothing
  78         } else if (cur_time - first_time >= BUSY_INFO_TRESHOLD &&
  79                         prev_time - first_time < BUSY_INFO_TRESHOLD) {
  80                 infostream << "SQLite3 database has been locked for "
  81                         << cur_time - first_time << " ms." << std::endl;
  82         } else if (cur_time - first_time >= BUSY_WARNING_TRESHOLD &&
  83                         prev_time - first_time < BUSY_WARNING_TRESHOLD) {
  84                 warningstream << "SQLite3 database has been locked for "
  85                         << cur_time - first_time << " ms." << std::endl;
  86         } else if (cur_time - first_time >= BUSY_ERROR_TRESHOLD &&
  87                         prev_time - first_time < BUSY_ERROR_TRESHOLD) {
  88                 errorstream << "SQLite3 database has been locked for "
  89                         << cur_time - first_time << " ms; this causes lag." << std::endl;
  90         } else if (cur_time - first_time >= BUSY_FATAL_TRESHOLD &&
  91                         prev_time - first_time < BUSY_FATAL_TRESHOLD) {
  92                 errorstream << "SQLite3 database has been locked for "
  93                         << cur_time - first_time << " ms - giving up!" << std::endl;
  94         } else if ((cur_time - first_time) / BUSY_ERROR_INTERVAL !=
  95                         (prev_time - first_time) / BUSY_ERROR_INTERVAL) {
  96                 // Safety net: keep reporting every BUSY_ERROR_INTERVAL
  97                 errorstream << "SQLite3 database has been locked for "
  98                         << (cur_time - first_time) / 1000 << " seconds!" << std::endl;
  99         }
 100
 101         prev_time = cur_time;
 102
 103         // Make sqlite transaction fail if delay exceeds BUSY_FATAL_TRESHOLD
 104         return cur_time - first_time < BUSY_FATAL_TRESHOLD;
 105 }
 106
 107
 108 Database_SQLite3::Database_SQLite3(const std::string &savedir) :
 109         m_initialized(false),
 110         m_savedir(savedir),
 111         m_database(NULL),
 112         m_stmt_read(NULL),
 113         m_stmt_write(NULL),
 114         m_stmt_list(NULL),
 115         m_stmt_delete(NULL),
 116         m_stmt_begin(NULL),
 117         m_stmt_end(NULL)
 118 {
 119 }
 120
 121 void Database_SQLite3::beginSave() {
 122         verifyDatabase();
 123         SQLRES(sqlite3_step(m_stmt_begin), SQLITE_DONE,
 124                 "Failed to start SQLite3 transaction");
 125         sqlite3_reset(m_stmt_begin);
 126 }
 127
 128 void Database_SQLite3::endSave() {
 129         verifyDatabase();
 130         SQLRES(sqlite3_step(m_stmt_end), SQLITE_DONE,
 131                 "Failed to commit SQLite3 transaction");
 132         sqlite3_reset(m_stmt_end);
 133 }
 134
 135 void Database_SQLite3::openDatabase()
 136 {
 137         if (m_database) return;
 138
 139         std::string dbp = m_savedir + DIR_DELIM + "map.sqlite";
 140
 141         // Open the database connection
 142
 143         if (!fs::CreateAllDirs(m_savedir)) {
 144                 infostream << "Database_SQLite3: Failed to create directory \""
 145                         << m_savedir << "\"" << std::endl;
 146                 throw FileNotGoodException("Failed to create database "
 147                                 "save directory");
 148         }
 149
 150         bool needs_create = !fs::PathExists(dbp);
 151
 152         SQLOK(sqlite3_open_v2(dbp.c_str(), &m_database,
 153                         SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL),
 154                 std::string("Failed to open SQLite3 database file ") + dbp);
 155
 156         SQLOK(sqlite3_busy_handler(m_database, Database_SQLite3::busyHandler,
 157                 m_busy_handler_data), "Failed to set SQLite3 busy handler");
 158
 159         if (needs_create) {
 160                 createDatabase();
 161         }
 162
 163         std::string query_str = std::string("PRAGMA synchronous = ")
 164                          + itos(g_settings->getU16("sqlite_synchronous"));
 165         SQLOK(sqlite3_exec(m_database, query_str.c_str(), NULL, NULL, NULL),
 166                 "Failed to modify sqlite3 synchronous mode");
 167 }
 168
 169 void Database_SQLite3::verifyDatabase()
 170 {
 171         if (m_initialized) return;
 172
 173         openDatabase();
 174
 175         PREPARE_STATEMENT(begin, "BEGIN");
 176         PREPARE_STATEMENT(end, "COMMIT");
 177         PREPARE_STATEMENT(read, "SELECT `data` FROM `blocks` WHERE `pos` = ? LIMIT 1");
 178 #ifdef __ANDROID__
 179         PREPARE_STATEMENT(write,  "INSERT INTO `blocks` (`pos`, `data`) VALUES (?, ?)");
 180 #else
 181         PREPARE_STATEMENT(write, "REPLACE INTO `blocks` (`pos`, `data`) VALUES (?, ?)");
 182 #endif
 183         PREPARE_STATEMENT(delete, "DELETE FROM `blocks` WHERE `pos` = ?");
 184         PREPARE_STATEMENT(list, "SELECT `pos` FROM `blocks`");
 185
 186         m_initialized = true;
 187
 188         verbosestream << "ServerMap: SQLite3 database opened." << std::endl;
 189 }
 190
 191 inline void Database_SQLite3::bindPos(sqlite3_stmt *stmt, const v3s16 &pos, int index)
 192 {
 193         SQLOK(sqlite3_bind_int64(stmt, index, getBlockAsInteger(pos)),
 194                 "Internal error: failed to bind query at " __FILE__ ":" TOSTRING(__LINE__));
 195 }
 196
 197 bool Database_SQLite3::deleteBlock(const v3s16 &pos)
 198 {
 199         verifyDatabase();
 200
 201         bindPos(m_stmt_delete, pos);
 202
 203         bool good = sqlite3_step(m_stmt_delete) == SQLITE_DONE;
 204         sqlite3_reset(m_stmt_delete);
 205
 206         if (!good) {
 207                 warningstream << "deleteBlock: Block failed to delete "
 208                         << PP(pos) << ": " << sqlite3_errmsg(m_database) << std::endl;
 209         }
 210         return good;
 211 }
 212
 213 bool Database_SQLite3::saveBlock(const v3s16 &pos, const std::string &data)
 214 {
 215         verifyDatabase();
 216
 217 #ifdef __ANDROID__
 218         /**
 219          * Note: For some unknown reason SQLite3 fails to REPLACE blocks on Android,
 220          * deleting them and then inserting works.
 221          */
 222         bindPos(m_stmt_read, pos);
 223
 224         if (sqlite3_step(m_stmt_read) == SQLITE_ROW) {
 225                 deleteBlock(pos);
 226         }
 227         sqlite3_reset(m_stmt_read);
 228 #endif
 229
 230         bindPos(m_stmt_write, pos);
 231         SQLOK(sqlite3_bind_blob(m_stmt_write, 2, data.data(), data.size(), NULL),
 232                 "Internal error: failed to bind query at " __FILE__ ":" TOSTRING(__LINE__));
 233
 234         SQLRES(sqlite3_step(m_stmt_write), SQLITE_DONE, "Failed to save block")
 235         sqlite3_reset(m_stmt_write);
 236
 237         return true;
 238 }
 239
 240 std::string Database_SQLite3::loadBlock(const v3s16 &pos)
 241 {
 242         verifyDatabase();
 243
 244         bindPos(m_stmt_read, pos);
 245
 246         if (sqlite3_step(m_stmt_read) != SQLITE_ROW) {
 247                 sqlite3_reset(m_stmt_read);
 248                 return "";
 249         }
 250         const char *data = (const char *) sqlite3_column_blob(m_stmt_read, 0);
 251         size_t len = sqlite3_column_bytes(m_stmt_read, 0);
 252
 253         std::string s;
 254         if (data)
 255                 s = std::string(data, len);
 256
 257         sqlite3_step(m_stmt_read);
 258         // We should never get more than 1 row, so ok to reset
 259         sqlite3_reset(m_stmt_read);
 260
 261         return s;
 262 }
 263
 264 void Database_SQLite3::createDatabase()
 265 {
 266         assert(m_database); // Pre-condition
 267         SQLOK(sqlite3_exec(m_database,
 268                 "CREATE TABLE IF NOT EXISTS `blocks` (\n"
 269                 "       `pos` INT PRIMARY KEY,\n"
 270                 "       `data` BLOB\n"
 271                 ");\n",
 272                 NULL, NULL, NULL),
 273                 "Failed to create database table");
 274 }
 275
 276 void Database_SQLite3::listAllLoadableBlocks(std::vector<v3s16> &dst)
 277 {
 278         verifyDatabase();
 279
 280         while (sqlite3_step(m_stmt_list) == SQLITE_ROW) {
 281                 dst.push_back(getIntegerAsBlock(sqlite3_column_int64(m_stmt_list, 0)));
 282         }
 283         sqlite3_reset(m_stmt_list);
 284 }
 285
 286 Database_SQLite3::~Database_SQLite3()
 287 {
 288         FINALIZE_STATEMENT(m_stmt_read)
 289         FINALIZE_STATEMENT(m_stmt_write)
 290         FINALIZE_STATEMENT(m_stmt_list)
 291         FINALIZE_STATEMENT(m_stmt_begin)
 292         FINALIZE_STATEMENT(m_stmt_end)
 293         FINALIZE_STATEMENT(m_stmt_delete)
 294
 295         SQLOK(sqlite3_close(m_database), "Failed to close database");
 296 }
 297