From fd86dd93dd44a826235feb0fd82aabcdaa79a65b Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 28 Feb 2017 13:59:11 +0100 Subject: [PATCH] Improve SQLite busy handling --- configure.ac | 2 +- src/libstore/sqlite.cc | 66 +++++++++++++++++++++++------------------- src/libstore/sqlite.hh | 6 +++- 3 files changed, 43 insertions(+), 31 deletions(-) diff --git a/configure.ac b/configure.ac index e6b11be2d..46b0ac065 100644 --- a/configure.ac +++ b/configure.ac @@ -265,7 +265,7 @@ AC_CHECK_FUNCS([setresuid setreuid lchown]) # Nice to have, but not essential. -AC_CHECK_FUNCS([strsignal posix_fallocate nanosleep sysconf]) +AC_CHECK_FUNCS([strsignal posix_fallocate sysconf]) # This is needed if bzip2 is a static library, and the Nix libraries diff --git a/src/libstore/sqlite.cc b/src/libstore/sqlite.cc index 7d6561212..a81e62dbd 100644 --- a/src/libstore/sqlite.cc +++ b/src/libstore/sqlite.cc @@ -3,6 +3,8 @@ #include +#include + namespace nix { [[noreturn]] void throwSQLiteError(sqlite3 * db, const format & f) @@ -13,27 +15,10 @@ namespace nix { if (!path) path = "(in-memory)"; if (err == SQLITE_BUSY || err == SQLITE_PROTOCOL) { - if (err == SQLITE_PROTOCOL) - printError("warning: SQLite database ‘%s’ is busy (SQLITE_PROTOCOL)", path); - else { - static bool warned = false; - if (!warned) { - printError("warning: SQLite database ‘%s’ is busy", path); - warned = true; - } - } - /* Sleep for a while since retrying the transaction right away - is likely to fail again. */ - checkInterrupt(); -#if HAVE_NANOSLEEP - struct timespec t; - t.tv_sec = 0; - t.tv_nsec = (random() % 100) * 1000 * 1000; /* <= 0.1s */ - nanosleep(&t, 0); -#else - sleep(1); -#endif - throw SQLiteBusy("%s: %s (in ‘%s’)", f.str(), sqlite3_errstr(err), path); + throw SQLiteBusy( + err == SQLITE_PROTOCOL + ? fmt("SQLite database ‘%s’ is busy (SQLITE_PROTOCOL)", path) + : fmt("SQLite database ‘%s’ is busy", path)); } else throw SQLiteError("%s: %s (in ‘%s’)", f.str(), sqlite3_errstr(err), path); @@ -58,24 +43,27 @@ SQLite::~SQLite() void SQLite::exec(const std::string & stmt) { - if (sqlite3_exec(db, stmt.c_str(), 0, 0, 0) != SQLITE_OK) - throwSQLiteError(db, format("executing SQLite statement ‘%s’") % stmt); + retrySQLite([&]() { + if (sqlite3_exec(db, stmt.c_str(), 0, 0, 0) != SQLITE_OK) + throwSQLiteError(db, format("executing SQLite statement ‘%s’") % stmt); + }); } -void SQLiteStmt::create(sqlite3 * db, const string & s) +void SQLiteStmt::create(sqlite3 * db, const string & sql) { checkInterrupt(); assert(!stmt); - if (sqlite3_prepare_v2(db, s.c_str(), -1, &stmt, 0) != SQLITE_OK) - throwSQLiteError(db, "creating statement"); + if (sqlite3_prepare_v2(db, sql.c_str(), -1, &stmt, 0) != SQLITE_OK) + throwSQLiteError(db, fmt("creating statement ‘%s’", sql)); this->db = db; + this->sql = sql; } SQLiteStmt::~SQLiteStmt() { try { if (stmt && sqlite3_finalize(stmt) != SQLITE_OK) - throwSQLiteError(db, "finalizing statement"); + throwSQLiteError(db, fmt("finalizing statement ‘%s’", sql)); } catch (...) { ignoreException(); } @@ -132,14 +120,14 @@ void SQLiteStmt::Use::exec() int r = step(); assert(r != SQLITE_ROW); if (r != SQLITE_DONE) - throwSQLiteError(stmt.db, "executing SQLite statement"); + throwSQLiteError(stmt.db, fmt("executing SQLite statement ‘%s’", stmt.sql)); } bool SQLiteStmt::Use::next() { int r = step(); if (r != SQLITE_DONE && r != SQLITE_ROW) - throwSQLiteError(stmt.db, "executing SQLite query"); + throwSQLiteError(stmt.db, fmt("executing SQLite query ‘%s’", stmt.sql)); return r == SQLITE_ROW; } @@ -186,4 +174,24 @@ SQLiteTxn::~SQLiteTxn() } } +void handleSQLiteBusy(const SQLiteBusy & e) +{ + static std::atomic lastWarned{0}; + + time_t now = time(0); + + if (now > lastWarned + 10) { + lastWarned = now; + printError("warning: %s", e.what()); + } + + /* Sleep for a while since retrying the transaction right away + is likely to fail again. */ + checkInterrupt(); + struct timespec t; + t.tv_sec = 0; + t.tv_nsec = (random() % 100) * 1000 * 1000; /* <= 0.1s */ + nanosleep(&t, 0); +} + } diff --git a/src/libstore/sqlite.hh b/src/libstore/sqlite.hh index 4d347a2e5..14a7a0dd8 100644 --- a/src/libstore/sqlite.hh +++ b/src/libstore/sqlite.hh @@ -30,8 +30,9 @@ struct SQLiteStmt { sqlite3 * db = 0; sqlite3_stmt * stmt = 0; + std::string sql; SQLiteStmt() { } - SQLiteStmt(sqlite3 * db, const std::string & s) { create(db, s); } + SQLiteStmt(sqlite3 * db, const std::string & sql) { create(db, sql); } void create(sqlite3 * db, const std::string & s); ~SQLiteStmt(); operator sqlite3_stmt * () { return stmt; } @@ -94,6 +95,8 @@ MakeError(SQLiteBusy, SQLiteError); [[noreturn]] void throwSQLiteError(sqlite3 * db, const format & f); +void handleSQLiteBusy(const SQLiteBusy & e); + /* Convenience function for retrying a SQLite transaction when the database is busy. */ template @@ -103,6 +106,7 @@ T retrySQLite(std::function fun) try { return fun(); } catch (SQLiteBusy & e) { + handleSQLiteBusy(e); } } }