.sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

edwinsn · 2014-07-28 14:09:23

Arnaud,

I've noticed many times there are .sqlitedb-wal and .sqlitedb-shm leftover files. I use TSQLRestClientDB, I do have WAL enabled, with the intention of getting maximum stability; I do have have multiple threads starting/commiting transactions.

Any help would be appreciated!

edwinsn · 2014-07-28 14:13:03

additional info, My derived TransactionBegin() is protected with a TOmniMREW (mulit-reader-exclusive-writer) lock, like this:

function TDataStoreClient.TransactionBegin(aTable: TSQLRecordClass; SessionID:
    cardinal): boolean;
begin
  //if the db server is in the same process, we protect the writing operation from
  //being executed by multi threads.
  if IsServerInSameProcess then
    gAppScopeDbLock.EnterWriteLock; //this is an global lock

  result := inherited TransactionBegin(aTable, SessionID);
end;

procedure TDataStoreClient.Commit(SessionID: cardinal);
begin
  try
    inherited Commit(SessionID);
  finally
    if IsServerInSameProcess then
      gAppScopeDbLock.ExitWriteLock;
  end;
end;

Any logical problems in my derived TSQLRestClientDB class?

ab · 2014-07-28 16:42:44

We recommend not to use TransactionBegin from client sides, but a BATCH with a positive argument to BatchStart() for automatic transaction on the server side.

You should not need to do anything special on the client side for transaction protection.
It is already part of the TSQLRestServer.URI method, AFAIR.

edwinsn · 2014-07-29 03:41:44

Arnaud,

as per this discussion http://synopse.info/forum/viewtopic.php?id=1905

the URI methods doesn't return the actual database error, which we need.

ab · 2014-07-29 05:57:09

Both BATCH and regular CRUD methods return an error code.
From the client point of view, it is enough to know if it succeeded or not.

edwinsn · 2014-07-29 06:45:57

Arnaud, this is not a real client/server app, but a single EXE USING TSQLRestClientDB, so it really need to handle the actual sqlite server. Do you think if I switch to TSQLRestServerDB will fix the problem?

mORMot Open Source

#1 2014-07-28 14:09:23

.sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

#2 2014-07-28 14:13:03

Re: .sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

#3 2014-07-28 16:42:44

Re: .sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

#4 2014-07-29 03:41:44

Re: .sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

#5 2014-07-29 05:57:09

Re: .sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

#6 2014-07-29 06:45:57

Re: .sqlitedb-wal and .sqlitedb-shm leftover files, what might happened?

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