From e33f67ff0b02cc8fc2e0024dd87a6d61467df177 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 24 Feb 2010 16:30:20 +0000 Subject: [PATCH] * Refactor the upgrade / database initialisation logic a bit. --- src/libstore/local-store.cc | 121 +++++++++++++++++++----------------- src/libstore/local-store.hh | 4 +- 2 files changed, 64 insertions(+), 61 deletions(-) diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index bfb253bc1..7e205a9bf 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -205,52 +205,43 @@ LocalStore::LocalStore() lockFile(globalLock, ltRead, true); } - /* Open the Nix database. */ - if (sqlite3_open_v2((nixDBPath + "/db.sqlite").c_str(), &db.db, - SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0) != SQLITE_OK) - throw Error("cannot open SQLite database"); - - if (sqlite3_busy_timeout(db, 60000) != SQLITE_OK) - throw SQLiteError(db, "setting timeout"); - - if (sqlite3_exec(db, "pragma foreign_keys = 1;", 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "enabling foreign keys"); - - /* !!! check whether sqlite has been built with foreign key - support */ - - /* Whether SQLite should fsync(). "Normal" synchronous mode - should be safe enough. If the user asks for it, don't sync at - all. This can cause database corruption if the system - crashes. */ - string syncMode = queryBoolSetting("fsync-metadata", true) ? "normal" : "off"; - if (sqlite3_exec(db, ("pragma synchronous = " + syncMode + ";").c_str(), 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "setting synchronous mode"); - - /* Use `truncate' journal mode, which should be a bit faster. */ - if (sqlite3_exec(db, "pragma main.journal_mode = truncate;", 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "setting journal mode"); - /* Check the current database schema and if necessary do an - upgrade. !!! Race condition: several processes could start - the upgrade at the same time. */ + upgrade. */ int curSchema = getSchema(); if (curSchema > nixSchemaVersion) throw Error(format("current Nix store schema is version %1%, but I only support %2%") % curSchema % nixSchemaVersion); - if (curSchema == 0) { /* new store */ + + else if (curSchema == 0) { /* new store */ curSchema = nixSchemaVersion; - initSchema(); + openDB(true); writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str()); } - else if (curSchema == 1) throw Error("your Nix store is no longer supported"); - else if (curSchema < 5) - throw Error( - "Your Nix store has a database in Berkeley DB format,\n" - "which is no longer supported. To convert to the new format,\n" - "please upgrade Nix to version 0.12 first."); - else if (curSchema < 6) upgradeStore6(); - else prepareStatements(); + + else if (curSchema < nixSchemaVersion) { + if (curSchema < 5) + throw Error( + "Your Nix store has a database in Berkeley DB format,\n" + "which is no longer supported. To convert to the new format,\n" + "please upgrade Nix to version 0.12 first."); + + if (!lockFile(globalLock, ltWrite, false)) { + printMsg(lvlError, "waiting for exclusive access to the Nix store..."); + lockFile(globalLock, ltWrite, true); + } + + /* Get the schema version again, because another process may + have performed the upgrade already. */ + curSchema = getSchema(); + + if (curSchema < 6) upgradeStore6(); + + writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str()); + + lockFile(globalLock, ltRead, true); + } + + else openDB(false); } @@ -280,19 +271,42 @@ int LocalStore::getSchema() } -void LocalStore::initSchema() +void LocalStore::openDB(bool create) { + /* Open the Nix database. */ + if (sqlite3_open_v2((nixDBPath + "/db.sqlite").c_str(), &db.db, + SQLITE_OPEN_READWRITE | (create ? SQLITE_OPEN_CREATE : 0), 0) != SQLITE_OK) + throw Error("cannot open SQLite database"); + + if (sqlite3_busy_timeout(db, 60000) != SQLITE_OK) + throw SQLiteError(db, "setting timeout"); + + if (sqlite3_exec(db, "pragma foreign_keys = 1;", 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "enabling foreign keys"); + + /* !!! check whether sqlite has been built with foreign key + support */ + + /* Whether SQLite should fsync(). "Normal" synchronous mode + should be safe enough. If the user asks for it, don't sync at + all. This can cause database corruption if the system + crashes. */ + string syncMode = queryBoolSetting("fsync-metadata", true) ? "normal" : "off"; + if (sqlite3_exec(db, ("pragma synchronous = " + syncMode + ";").c_str(), 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "setting synchronous mode"); + + /* Use `truncate' journal mode, which should be a bit faster. */ + if (sqlite3_exec(db, "pragma main.journal_mode = truncate;", 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "setting journal mode"); + + /* Initialise the database schema, if necessary. */ + if (create) { #include "schema.sql.hh" + if (sqlite3_exec(db, (const char *) schema, 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "initialising database schema"); + } - if (sqlite3_exec(db, (const char *) schema, 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "initialising database schema"); - - prepareStatements(); -} - - -void LocalStore::prepareStatements() -{ + /* Prepare SQL statements. */ stmtRegisterValidPath.create(db, "insert or replace into ValidPaths (path, hash, registrationTime, deriver) values (?, ?, ?, ?);"); stmtAddReference.create(db, @@ -1225,14 +1239,9 @@ ValidPathInfo LocalStore::queryPathInfoOld(const Path & path) /* Upgrade from schema 5 (Nix 0.12) to schema 6 (Nix >= 0.15). */ void LocalStore::upgradeStore6() { - if (!lockFile(globalLock, ltWrite, false)) { - printMsg(lvlError, "waiting for exclusive access to the Nix store..."); - lockFile(globalLock, ltWrite, true); - } - printMsg(lvlError, "upgrading Nix store to new schema (this may take a while)..."); - initSchema(); + openDB(true); PathSet validPaths = queryValidPathsOld(); @@ -1256,10 +1265,6 @@ void LocalStore::upgradeStore6() std::cerr << "\n"; txn.commit(); - - writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str()); - - lockFile(globalLock, ltRead, true); } diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh index 1e4080bec..0c5f04158 100644 --- a/src/libstore/local-store.hh +++ b/src/libstore/local-store.hh @@ -209,9 +209,7 @@ private: int getSchema(); - void initSchema(); - - void prepareStatements(); + void openDB(bool create); unsigned long long queryValidPathId(const Path & path);