So PL/SQL Developer becomes slow if you have multiple connections open AND keep PL/SQL Developer running for a few days. We'll check it out.

That is one way that can make it slow, but not the only way. As stated above it also gets slow pretty quickly in this scenario:
[quote]You get easily slow response times and see lots of sandclocks when comparing half a dozen schemas each with a few hundred objects. Just switching to the PL/SQL Develoepr application takes about 10 sec. Windows then even even detected unresponsiveness and suggested to kill the PL/SQL Developer instance. Some compares also seem to have hung up completely and don't seem to move forward anymore. Switching from one compare window to the next also already takes many seconds.[/quote]
I actually just used 3 schemas, so 3 different connections, i.e. schema A, B, C. I was comparing A with B, B with A, A with C, C with A, B with C and C with A. This got me annoyingly slow response times in just a couple of minutes.
Are you still unsuccessful in recreating any slow response scenario? Is there anything we can still do, to help you figure out the reason for this issue? Is the any way to figure out what PL/SQL is doing, when it's in its slow response mode and how it ends up getting there?
Can you give us any indication by when you expect this problem to be solved and make v11 respond quickly enough so that it's worth using it for all the users affected too much by this issue as well?

Marco - I believe that problem appears primary when open multiple connections, no matter how long plsqldeveloper was opened. Ive done my test again now, Ive opened new plsqldeveloper, for one DB, it was quick. Then Ive open windows for another 3 databases and it become slow. Switching between windows takes 2 or 3 s. Plsqldeveloper I had open from yesterday with connected only to one database is still quick. So I believe that main problem will not be with time, but with multiple connections.

Pavel

[quote=PMrb]Marco - I believe that problem appears primary when open multiple connections, no matter how long plsqldeveloper was opened.[/quote]
I tried this scenario: opened 4 database connections over a WAN, opened 3 different windows (SQL, Test, Program) for each connection. Ran various SQL statements and PL/SQL code in each window. Performance remains excellent, switching between windows takes 0 seconds.

Can you let me know your settings from the Preferences > Oracle / Connections preference page?

Now I aggree with Pavel that multiple connections are the problem. Here are my settings from the Preferences > Oracle / Connections preference page:
[Oracle]
SessionMode=0
OpenTransaction=2
CheckConnection=False
SelectedHome=OraClient11g_home1_32bit
OCIFile=
AllowMultipleConnections=True
ConnectionsPinnedByDefault=False
AutoCloseConnections=True
StoreConnectionsHistory=True
StoreConnectionsPassword=True

[Oracle]
SessionMode=0
OpenTransaction=2
CheckConnection=True
SelectedHome=
OCIFile=c:\Oracle\product\12.1.0\client_1\BIN\oci.dll
AllowMultipleConnections=True
ConnectionsPinnedByDefault=True
AutoCloseConnections=True
StoreConnectionsHistory=False
StoreConnectionsPassword=False

So
Session mode - mutli session
logof with open transaction - ask
check connection - check
Oracle home - empty
Oci library - c:\Oracle\product\12.1.0\client_1\BIN\oci.dll

Multiple connections
Allow multiple connections - check
Pin window connections by default - check
Automatically close unused connections - check
Store recent history - empty
Store with password - empty

[quote=Marco Kalter]switching between windows takes 0 seconds[/quote]
Switching between program windows has never taken 0 seconds for me. At least not in the same way that switching between tabs in Notepad++ or Excel or any other program takes 0 seconds. Perhaps they all take <1 second, but PL/SQL Developer is noticeably slower. If that's not the case on your computer, maybe that's related to why you can't reproduce some of the other problems.

I've always blamed the slowness on PL/SQL Developer refreshing parts of the GUI that it doesn't need to. For example, when I switch between two blank SQL windows I can see a flicker in my Object Browser tab as if it's refreshing that as well (and from network traffic mentioning "last_ddl_time" I believe that it is). Since the Object Browser has its own refresh button, I don't understand that.
Other times when opening a new sql window I can watch PL/SQL Developer un-maximize the current window, open the new window un-maximized, and then maximize the new one. I don't see this when switching windows, but if it happens there too (just too fast for me to notice) I'm sure it adds a delay.

Alright, I have the following reproducable test case:

1. Open pl/sql developer without connecting to a database
2. Open two SQL windows
3. Un-maximize the SQL windows (for easier observations)
=> switching back and forth between the two SQL windows by clicking them takes about 0.2 seconds

4. connect to a database (connections panel, right-click "connect as main")
=> switching back and forth between the two SQL windows by clicking them now takes about 1.0 seconds

5. session -> log off -> all
=> switching back and forth between the two SQL windows by clicking them still takes about 1.0 seconds
(note: the SQL windows still show the connection in their status bars, even though they're supposedly disconnected)

6. change connection -> disconnect in the two SQL windows status bars
=> switching back and forth between the two SQL windows by clicking them now takes about 2.3 seconds, and another 2.0 seconds before the cursor actually stars blinking.

I don't know how this relates to what others are experiencing, but hopefully it helps track down at least one of the problems.

I tried "OldLocking=1" but it did not make a difference.

Version 11.0.2.1766
Windows 8 (64-bit) 6.2 Build 9200
"C:\Program Files (x86)\PLSQL Developer\plsqldev.exe" nosplash nologon instantclient="C:\Program Files (x86)\Oracle\instantclient_11_2"

Unfortunately this does not reproduce the issue for me. Window switching is always instantaneous.

To obtain some more diagnostic information, can you modify the shortcut and add the DebugSQL parameter? For example:

"C:\Program Files\PLSQL Developer\plsqldev.exe" DebugSQL

Redo the steps above and send me the debug.txt file that is generated in the PL/SQL Developer directory or in the %APPDATA%\PLSQL Developer directory (e.g. C:\Users\<User>\AppData\Roaming\PLSQL Developer).

Done. debug.txt and analysis sent to support@allroundautomations.com