I?m very excited that I re-produce the SQLITE_BUSY code in a simple demo.
Here is my test code,
void showResultCode(int resultCode)
{
if (resultCode!=SQLITE_DONEresultCode!=SQLITE_OKresultCode!=SQLITE_ROW) {
NSLog(@"unexperted result %d", resultCode);
}
}
void SQLiteLog(void* userInfo, int ret, const char* msg)
{
NSLog(@"ret=%d, msg=%s", ret, msg);
}
void write(const char* path)
{
int code = SQLITE_OK;
sqlite3* handle;
showResultCode(sqlite3_open(path, handle));
sqlite3_exec(handle, "PRAGMA journal_mode=WAL", nullptr, nullptr, nullptr);
sqlite3_exec(handle, "create table test(id integer);", nullptr, nullptr,
nullptr);
sqlite3_stmt* stmt = nullptr;
showResultCode(sqlite3_exec(handle, "BEGIN IMMEDIATE", nullptr, nullptr,
nullptr));
for (int i = 0; i 2; i++) {
showResultCode(sqlite3_prepare(handle, [NSString stringWithFormat:@"insert
into test values(%d);", i].UTF8String, -1, stmt, nullptr));
showResultCode(sqlite3_step(stmt));
}
showResultCode(sqlite3_exec(handle, "COMMIT", nullptr, nullptr, nullptr));
showResultCode(sqlite3_finalize(stmt));
showResultCode(sqlite3_close(handle));
}
int main(int argc, char * argv[])
{
sqlite3_config(SQLITE_CONFIG_LOG, SQLiteLog, NULL);
const char* path = "/Users/sanhuazhang/Desktop/test.db";
write(path);
return 1;
}
The console result is ?unexperted result 5?, which indicates SQLITE_BUSY. It
happens at code?sqlite3_close?.one of the strange things is that?SQLiteLog?
print nothing.
AndYou can see that I only write some data using transaction. How could
SQLITE_BUSY happened while sqlite.org said that?The SQLITE_BUSY result code
indicates that the database file could not be written (or in some cases read)
because of concurrent activity by some other database connection.?.
So, as a conclusion, I confuse that why the result code of?sqlite3_close" is
SQLITE_BUSY and is it possible that SQLITE_BUSY returned by other function in
this situation(single process,single thread,single connection).
????
???:sanhua.zhsanhua.zh at foxmail.com
???:sqlite-userssqlite-users at mailinglists.sqlite.org
????:2015?12?14?(??)?17:21
??:[sqlite] Why SQLITE_BUSY?
I queue all my db operation into one thread with single sqlite conn. neither
multi-thread nor multi-process operation happened.But some SQLITE_BUSY error
code still be catched. I can not re-produce this error code indeveloping
environment,because it happen in alow probability. I only catch this error
report online. So how did it happen? I guess that, when WAL reach the
checkpoint, sqlite will write the data back to original db file in background
thread. So writing will be busy at this time. But I?m not sure. I hope that you
will not stint your criticism _______________________________________________
sqlite-users mailing list sqlite-users at mailinglists.sqlite.org
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
