From e4907411c2d902215d1a18456ce8b0c653650461 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 1 Sep 2010 11:36:22 +0000 Subject: [PATCH] * Only do "pragma journal_mode = ..." if the current journal mode differs from the desired mode. There is an open SQLite ticket `Executing "PRAGMA journal_mode" may delete journal file while it is in use.' --- src/libstore/local-store.cc | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index fd6ad6464..c0c1461b4 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -303,7 +303,16 @@ void LocalStore::openDB(bool create) The downside is that it doesn't work over NFS, so allow truncate mode alternatively. */ string mode = queryBoolSetting("use-sqlite-wal", true) ? "wal" : "truncate"; - if (sqlite3_exec(db, ("pragma main.journal_mode = " + mode + ";").c_str(), 0, 0, 0) != SQLITE_OK) + string prevMode; + { + SQLiteStmt stmt; + stmt.create(db, "pragma main.journal_mode;"); + if (sqlite3_step(stmt) != SQLITE_ROW) + throw SQLiteError(db, "querying journal mode"); + prevMode = string((const char *) sqlite3_column_text(stmt, 0)); + } + if (prevMode != mode && + sqlite3_exec(db, ("pragma main.journal_mode = " + mode + ";").c_str(), 0, 0, 0) != SQLITE_OK) throw SQLiteError(db, "setting journal mode"); /* Increase the auto-checkpoint interval to 8192 pages. This