lix/src/libstore/sqlite.cc
Robert Hensing 8a0ef5d58e sqlite.cc: Add SQL tracing
Set environment variable NIX_DEBUG_SQLITE_TRACES=1 to log all sql statements.
2023-02-07 23:34:36 +01:00

265 lines
7 KiB
C++

#include "sqlite.hh"
#include "globals.hh"
#include "util.hh"
#include <sqlite3.h>
#include <atomic>
namespace nix {
SQLiteError::SQLiteError(const char *path, const char *errMsg, int errNo, int extendedErrNo, int offset, hintformat && hf)
: Error(""), path(path), errMsg(errMsg), errNo(errNo), extendedErrNo(extendedErrNo), offset(offset)
{
auto offsetStr = (offset == -1) ? "" : "at offset " + std::to_string(offset) + ": ";
err.msg = hintfmt("%s: %s%s, %s (in '%s')",
normaltxt(hf.str()),
offsetStr,
sqlite3_errstr(extendedErrNo),
errMsg,
path ? path : "(in-memory)");
}
[[noreturn]] void SQLiteError::throw_(sqlite3 * db, hintformat && hf)
{
int err = sqlite3_errcode(db);
int exterr = sqlite3_extended_errcode(db);
int offset = sqlite3_error_offset(db);
auto path = sqlite3_db_filename(db, nullptr);
auto errMsg = sqlite3_errmsg(db);
if (err == SQLITE_BUSY || err == SQLITE_PROTOCOL) {
auto exp = SQLiteBusy(path, errMsg, err, exterr, offset, std::move(hf));
exp.err.msg = hintfmt(
err == SQLITE_PROTOCOL
? "SQLite database '%s' is busy (SQLITE_PROTOCOL)"
: "SQLite database '%s' is busy",
path ? path : "(in-memory)");
throw exp;
} else
throw SQLiteError(path, errMsg, err, exterr, offset, std::move(hf));
}
static void traceSQL(void * x, const char * sql)
{
// wacky delimiters:
// so that we're quite unambiguous without escaping anything
// notice instead of trace:
// so that this can be enabled without getting the firehose in our face.
notice("SQL<[%1%]>", sql);
};
SQLite::SQLite(const Path & path, bool create)
{
// useSQLiteWAL also indicates what virtual file system we need. Using
// `unix-dotfile` is needed on NFS file systems and on Windows' Subsystem
// for Linux (WSL) where useSQLiteWAL should be false by default.
const char *vfs = settings.useSQLiteWAL ? 0 : "unix-dotfile";
int flags = SQLITE_OPEN_READWRITE;
if (create) flags |= SQLITE_OPEN_CREATE;
int ret = sqlite3_open_v2(path.c_str(), &db, flags, vfs);
if (ret != SQLITE_OK) {
const char * err = sqlite3_errstr(ret);
throw Error("cannot open SQLite database '%s': %s", path, err);
}
if (sqlite3_busy_timeout(db, 60 * 60 * 1000) != SQLITE_OK)
SQLiteError::throw_(db, "setting timeout");
if (getEnv("NIX_DEBUG_SQLITE_TRACES") == "1") {
// To debug sqlite statements; trace all of them
sqlite3_trace(db, &traceSQL, nullptr);
}
exec("pragma foreign_keys = 1");
}
SQLite::~SQLite()
{
try {
if (db && sqlite3_close(db) != SQLITE_OK)
SQLiteError::throw_(db, "closing database");
} catch (...) {
ignoreException();
}
}
void SQLite::isCache()
{
exec("pragma synchronous = off");
exec("pragma main.journal_mode = truncate");
}
void SQLite::exec(const std::string & stmt)
{
retrySQLite<void>([&]() {
if (sqlite3_exec(db, stmt.c_str(), 0, 0, 0) != SQLITE_OK)
SQLiteError::throw_(db, "executing SQLite statement '%s'", stmt);
});
}
uint64_t SQLite::getLastInsertedRowId()
{
return sqlite3_last_insert_rowid(db);
}
void SQLiteStmt::create(sqlite3 * db, const std::string & sql)
{
checkInterrupt();
assert(!stmt);
if (sqlite3_prepare_v2(db, sql.c_str(), -1, &stmt, 0) != SQLITE_OK)
SQLiteError::throw_(db, "creating statement '%s'", sql);
this->db = db;
this->sql = sql;
}
SQLiteStmt::~SQLiteStmt()
{
try {
if (stmt && sqlite3_finalize(stmt) != SQLITE_OK)
SQLiteError::throw_(db, "finalizing statement '%s'", sql);
} catch (...) {
ignoreException();
}
}
SQLiteStmt::Use::Use(SQLiteStmt & stmt)
: stmt(stmt)
{
assert(stmt.stmt);
/* Note: sqlite3_reset() returns the error code for the most
recent call to sqlite3_step(). So ignore it. */
sqlite3_reset(stmt);
}
SQLiteStmt::Use::~Use()
{
sqlite3_reset(stmt);
}
SQLiteStmt::Use & SQLiteStmt::Use::operator () (std::string_view value, bool notNull)
{
if (notNull) {
if (sqlite3_bind_text(stmt, curArg++, value.data(), -1, SQLITE_TRANSIENT) != SQLITE_OK)
SQLiteError::throw_(stmt.db, "binding argument");
} else
bind();
return *this;
}
SQLiteStmt::Use & SQLiteStmt::Use::operator () (const unsigned char * data, size_t len, bool notNull)
{
if (notNull) {
if (sqlite3_bind_blob(stmt, curArg++, data, len, SQLITE_TRANSIENT) != SQLITE_OK)
SQLiteError::throw_(stmt.db, "binding argument");
} else
bind();
return *this;
}
SQLiteStmt::Use & SQLiteStmt::Use::operator () (int64_t value, bool notNull)
{
if (notNull) {
if (sqlite3_bind_int64(stmt, curArg++, value) != SQLITE_OK)
SQLiteError::throw_(stmt.db, "binding argument");
} else
bind();
return *this;
}
SQLiteStmt::Use & SQLiteStmt::Use::bind()
{
if (sqlite3_bind_null(stmt, curArg++) != SQLITE_OK)
SQLiteError::throw_(stmt.db, "binding argument");
return *this;
}
int SQLiteStmt::Use::step()
{
return sqlite3_step(stmt);
}
void SQLiteStmt::Use::exec()
{
int r = step();
assert(r != SQLITE_ROW);
if (r != SQLITE_DONE)
SQLiteError::throw_(stmt.db, fmt("executing SQLite statement '%s'", sqlite3_expanded_sql(stmt.stmt)));
}
bool SQLiteStmt::Use::next()
{
int r = step();
if (r != SQLITE_DONE && r != SQLITE_ROW)
SQLiteError::throw_(stmt.db, fmt("executing SQLite query '%s'", sqlite3_expanded_sql(stmt.stmt)));
return r == SQLITE_ROW;
}
std::string SQLiteStmt::Use::getStr(int col)
{
auto s = (const char *) sqlite3_column_text(stmt, col);
assert(s);
return s;
}
int64_t SQLiteStmt::Use::getInt(int col)
{
// FIXME: detect nulls?
return sqlite3_column_int64(stmt, col);
}
bool SQLiteStmt::Use::isNull(int col)
{
return sqlite3_column_type(stmt, col) == SQLITE_NULL;
}
SQLiteTxn::SQLiteTxn(sqlite3 * db)
{
this->db = db;
if (sqlite3_exec(db, "begin;", 0, 0, 0) != SQLITE_OK)
SQLiteError::throw_(db, "starting transaction");
active = true;
}
void SQLiteTxn::commit()
{
if (sqlite3_exec(db, "commit;", 0, 0, 0) != SQLITE_OK)
SQLiteError::throw_(db, "committing transaction");
active = false;
}
SQLiteTxn::~SQLiteTxn()
{
try {
if (active && sqlite3_exec(db, "rollback;", 0, 0, 0) != SQLITE_OK)
SQLiteError::throw_(db, "aborting transaction");
} catch (...) {
ignoreException();
}
}
void handleSQLiteBusy(const SQLiteBusy & e)
{
static std::atomic<time_t> lastWarned{0};
time_t now = time(0);
if (now > lastWarned + 10) {
lastWarned = now;
logWarning({
.msg = hintfmt(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);
}
}