Thank you very much for your advice!
>to check that transaction
>wasn't committed yet you can connect to the database with external
>command while application is working and try to update or insert
>something. If it fails with message "The database file is locked" then
>application didn't commit transaction
Yes, you are right. Update fails with message "The database file is locked".
I inserted following statements:
const char *sql;
int commit = sqlite3_get_autocommit(db);
sqlite3_stmt *pStmt = sqlite3_next_stmt(db, NULL);
if(pStmt != NULL)
{
sql = sqlite3_sql(pStmt);
}
right after :
sqlite3_blob_close();
And received:
commit = 1;
pStmt != NULL
but
sql = NULL; //under debugger: pStmt->isPrepareV2 = 0; pStmt->zSql = NULL;
The results surprised me. I think that I do not have any
statement open yet sqlite3_next_stmt tells me that I have statement prepared
and pending. At the same time sqlite3_sql(pStmt) says that that statement is a
NULL statement.
I just got more confused.
Best regards,
Samuel
----- Original Message ----
From: Pavel Ivanov <paiva...@gmail.com>
To: General Discussion of SQLite Database <sqlite-users@sqlite.org>
Sent: Thu, February 4, 2010 2:07:12 PM
Subject: Re: [sqlite] When incremental write is committed to the hard drive?
> 1) What else can prevent incremental data to be written to the hard drive?
Besides all that I mentioned only explicit BEGIN statement can open
transaction and thus prevent anything after that from being written to
disk immediately until COMMIT is executed. What you can do now is
first of all use sqlite3_get_autocommit function
(http://www.sqlite.org/c3ref/get_autocommit.html) after closing blob
handle to check that transaction should be automatically committed.
But I'm not sure that it will return 0 if some SELECT statement is in
progress. To check that you can call sqlite3_next_stmt(db, NULL)
(http://www.sqlite.org/c3ref/next_stmt.html) to obtain pointer to the
statement that is still open (if you finalize all your statements then
this function should return NULL). If function returns some statement
you can use sqlite3_sql (http://www.sqlite.org/c3ref/sql.html) to see
what statement is at fault.
> 2) Is there a way to force a write to the hard drive?
Nothing but COMMIT statement (or auto-commit) can force new and
changed data to be written on disk. BTW, to check that transaction
wasn't committed yet you can connect to the database with external
command while application is working and try to update or insert
something. If it fails with message "The database file is locked" then
application didn't commit transaction. If update succeeds and you
still cannot see changes made by application then you have some
problems with file system, but I hope you have not.
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