From 713cd7e9e7012a11d2347e9b1a5dee9b4d3c62c0 Mon Sep 17 00:00:00 2001 From: annalee <150648636+a-n-n-a-l-e-e@users.noreply.github.com> Date: Sat, 23 Mar 2024 06:41:33 +0000 Subject: [PATCH] truncate WAL files on exit Fix for https://github.com/NixOS/nix/issues/10300 https://github.com/lix-project/lix/commit/18a26202737a74f216d285d92bd4a84761788026 enabled persistent WAL files that will never get truncated. to fix this, journal_size_limit is set to 2^40, which results in the WAL files being truncated to 0 on exit, as well as limiting the WAL files to 2^40 bytes following a checkpoint. this aligns lix with the nix change: https://github.com/NixOS/nix/pull/10301 https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlpersistwal https://www.sqlite.org/pragma.html#pragma_journal_size_limit https://github.com/sqlite/sqlite/blob/ed517a708284b6e00b6ae5f1e3f702bbfcbd32ed/src/wal.c#L2518 PR-Link: https://github.com/lix-project/lix/pull/9 Co-Authored-By: paparodeo <170618376+paparodeo@users.noreply.github.com> Change-Id: I90ec1a467c92c582ff8c07dd363a4cf789782214 --- src/libstore/local-store.cc | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index 7bcbe3298..d92fafa1b 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -550,7 +550,12 @@ void LocalStore::openDB(State & state, bool create) if (mode == "wal" ) { /* persist the WAL files when the DB connection is closed. * This allows for read-only connections without any write permissions - * on the state directory to succeed on a closed database. */ + * on the state directory to succeed on a closed database. Setting the + * journal_size_limit to 2^40 bytes results in the WAL files getting + * truncated to 0 on exit and limits the on disk size of the WAL files + * to 2^40 bytes following a checkpoint */ + if (sqlite3_exec(db, "pragma main.journal_size_limit = 1099511627776;", 0, 0, 0) != SQLITE_OK) + SQLiteError::throw_(db, "setting journal_size_limit"); int enable = 1; if (sqlite3_file_control(db, NULL, SQLITE_FCNTL_PERSIST_WAL, &enable) != SQLITE_OK) SQLiteError::throw_(db, "setting persistent WAL mode");