Changes

Summary

1. merged
2. more elementary transaction implementation (despite fda3f7a158b9 and 9da65bc75610);
3. tuned signature;
4. proper check (amending 234f2ff9afe6);
5. more robust: exclude accidental nesting (synchronized block is re-entrant);
6. clarified errors;
7. removed junk (amending f8e3b228670c);
8. tuned output;
9. reuse SSH.Server connection for database server;
10. tuned source structure;
11. clarified check: uniform session_info_exists;
12. more complete check;
13. clarified signature: more specific exists_table --- avoid retrieving full list beforehand;
14. reuse database_server connection;
15. more informative trace;
16. reuse SSH.Server connection database server;
17. tuned output;
18. make double-sure that this is a transaction context, notably for LOCK TABLE;
19. more robust Java/Scala multithreading: transaction is always connection.synchronized;
20. clarified signature: proper Scala function for command-line tool;
21. tuned signature;
22. clarified signature: more operations;
23. more standard time unit;
24. clarified options;
25. tuned output;
26. global transaction_count;
27. tuned output;
28. tuned output;
29. prefer asynchronous operations: reduce time spent within synchronized_database("Build_Process.start_job");
30. clarified isabelle.transaction_log: support time_min (in ms);
31. more operations;
32. more informative trace;
33. support trace of transaction_lock via property "isabelle.transaction_log";
34. proper db.transaction_lock instead of adhoc clone (amending 2df0f3604a67);
35. tuned;
36. proper close() operation;
37. tuned comments;
38. more robust: avoid nested transactions (on disjoint tables);
39. potentially more robust: long-running operation only for build master, not workers;
40. less ambitions transactions (amending 3f3dcf9f53f1): TRANSACTION_SERIALIZABLE may lead to spurious rollback exceptions;
41. clarified signature: more operations;
42. clarified signature: more operations;
43. clarified signature;
44. clarified signature;
45. clarified signature: follow Store.open_database;
46. tuned;
47. clarified signature;
48. clarified signature: more uniform SSH.Port_Forwarding;
49. tuned signature;