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Wt crash randomly

Added by Gilles Maire 5 months ago

On my site I get a randomly crash if I click on a tab bar in my application quickly

I can reproduce the problem after more than 500 clicks when I run in debug mode with Wt lib compiled in debug too.

I got the message trace : [/ 6MrpuUywV2LP3TKq] [error] "Wt: decodeSignal(): signal 'ou0lc8c.render' not exposed"

and the crash come always in the same line of code in a thread. All of the threads are on return mutex*.mutex*; and the fault thread is on the line :

WWidget *parent() const { return parent_; } in WWidget.h called by WFileUpload.C

I have FileUpload in my application but the program crashes when I am not uploading.

An other problem I met : I maintain the CTRL R pressed for a while to have many reload of application and after 30 seconds the server crashes with Wt: fatal error: MySQL : Failed to connect to database server: Too many connections

Is it a way to avoid this second problem?

Thanks for your great job

Gilles


Replies (1)

RE: Wt crash randomly - Added by Roel Standaert 5 months ago

WWidget *parent() const { return parent_; } in WWidget.h called by WFileUpload.C

What is the rest of the backtrace? What is the value of this when that function is called?

An other problem I met : I maintain the CTRL R pressed for a while to have many reload of application and after 30 seconds the server crashes with Wt: fatal error: MySQL : Failed to connect to database server: Too many connections

I imagine this may happen if you are creating a new connection for every WApplication. If Wt does not receive a notification from the browser that the user has quit the application (since that notification is not guaranteed), then Wt will clean up the session after the session timeout (default is 600 seconds). You can tweak this timeout, or consider using a connection pool rather than creating a new connection for every WApplication (I'm guessing that's what you're doing).

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