mORMot Open Source

Don't like ZDBC transaction management. Always keep started transaction on server even if nobody is connected.
http://synopse.info/forum/viewtopic.php … 105#p14105

For http server investigate MS .Net server for Linux and Darwin https://github.com/aspnet/KestrelHttpServer
Based on libuv (core of node.js)
I look the code at https://github.com/aspnet/KestrelHttpSe … Networking
and try to port to pascal

Sorry for delay answer. This is more Zeoslib problem in transaction management.
For confirmation this is trace log for "28 - Simple RESTful ORM Server" from today mORMotNightlyBuild and today Zeoslib svn, only changes in server is:

  SynDBZEOS,
//  SynDBODBC,           // external DB access via ODBC
...
  aProps := TSQLDBZEOSConnectionProperties.Create('zdbc:firebird-2.5://Tomi-PC1:3025/c:\test\test.fdb?username=sysdba;password=masterkey;LibLocation=fbclient.dll','','','');
//  aProps := TODBCConnectionProperties.Create('','Driver=PostgreSQL Unicode'+
//      {$ifdef CPU64}'(x64)'+{$endif}';Database=postgres;'+
//      'Server=localhost;Port=5432;UID=postgres;Pwd=postgresPassword','','');

Firebird trace for start server, 3 times start client, stop server can be downloaded from:
http://halkyon.com/download/Trace1.zip
Look for Transaction ID column.
Ex. In start2 select from person is executed in transaction 12 and in same transaction is executed insert from start3.
Commit retaining on firebird server side is = to commit + start new transaction.
Also notice that transaction 9 and statement 44 is keep open to the end of server process. Do we need this open connection, transaction, statement (cursor)?
With "hard_commit=true" server crash on start no active transaction is started.

Do you test speed? For PostgreSQL auto commit work on server side with inserting begin and commit for every statements.
If you send
INSERT 1
INSERT 2
INSERT N
server will convert to
BEGIN
INSERT 1
COMMIT
BEGIN
INSERT 2
COMMIT
BEGIN
INSERT N
COMMIT
If you use explicit SQL level transaction in "Unit of Work"
BEGIN
INSERT 1
INSERT 2
INSERT N
COMMIT
No conversion on server side, also speed will increase

ZDBC and FireDAC use same client api fbclient.dll. Auto Commit is software emulated by ZDBC and FireDAC. In firebird API you must at minimum start transaction, execute statement and commit transaction. This is minimum 3 network request/response to Firebird server. Commit is not a statement in firebird api (yes it is network request to server). ZDBC is slower then FireDAC because of bad implementation of api or maybe FireDAC don't commit all data in time (commiting data on disconnect)

PK ID is big restriction to use mORMot to migrate my systems.
1. My POS system Ex. 1 Central office and 20 POS locations (1 central db and 20 remote db), every POS location have 1-20 clients (sales point). POS locations must work even if internet connection VPN is lost. My PK is ID_LOCATION, ID
2. My accounting system, 1 Accounting office have >100 customers, some customers replicate data to accounting office. My PK is ID_USER, ID
ID already contain fiscal year bit shift ex. 140000001 for 2014
ERP system in development SaaS is also planed with PK ID_USER, ID. Several customers will use same database as storage. Some performance test for 1000 customers confirm that it is best to have 10 database with 100 customers per db instead of 1000 db-s.
Db-s Firebird and PostgreSQL.

AB, G-Wan was active developed in 2012 and performance tests was questionable in the forum. After that forum was closed and deleted. The last version is from Mar 14 2013. It looks nice but don't have marked share. Core is epoll linux kernel lib.
libuv core of node.js is c++ tcp, multithreding, signalig lib, use IOCP  in win and epoll on linux. Not easy to use in pascal.

Do you try lNet library?
http://lnet.wordpress.com/
Use IOCP in windows, epoll in linux and Qevent in BSD.
You can test small http server, great performance on linux. Try sample source from svn repo.
Need some work in multithreding and polishing. lthreadevents.pp have some work for worker threads.
Open Source, FreePascal, my vote.