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Try to handle multiple connections better.
The session database is a hot spot. When multiple requests (e.g. 20)
come in at the same time session database contention can get great.
The original code didn't retry session database access when the open
failed. This resulted in errors at the client.
The second pass delayed 0.01 seconds and retried. It was better but we
still had multiple second stalls. I think the first request got in,
everybody else backed up and then retried at the same time. Again they
stepped on each other. With logging I would see many counters go all
the way to low single digits or to -1 indicating falure.
This pass uses randomint to generate delays from 0-.125 seconds in 5ms
increments. This performs better in testing. I rarely saw a counter
less than 13 (2 failed retries). Current logging starts after 6
failures and counts down until success or failure.
| author | John Rouillard <rouilj@ieee.org> |
|---|---|
| date | Thu, 16 Dec 2021 20:02:00 -0500 |
| parents | 33a1f03b9de0 |
| children | 9ca128103a3a |
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==================== Implementation notes ==================== [see also the roundup package docstring] There have been some modifications to the spec. I've marked these in the source with 'XXX' comments when I remember to. In short: Class.find() - may match multiple properties, uses keyword args. Class.filter() - isn't in the spec and it's very useful to have at the Class level. CGI interface index view specifier layout part - lose the '+' from the sorting arguments (it's a reserved URL character ;). Just made no prefix mean ascending and '-' prefix descending. ItemClass - renamed to IssueClass to better match it only having one hypderdb class "issue". Allowing > 1 hyperdb class breaks the "superseder" multilink (since it can only link to one thing, and we'd want bugs to link to support and vice-versa). template - the call="link()" is handled by special-case mechanisms in my top-level CGI handler. In a nutshell, the handler looks for a method on itself called 'index%s' or 'item%s' where %s is a class. Most items pass on to the templating mechanism, but the file class _always_ does downloading. It'll probably stay this way too... template - call="link(property)" may be used to link "the current item" (from an index) - the link text is the property specified. template - added functions that I found very useful: List, History and Submit. template - items must specify the message lists, history, etc. Having them by default was sometimes not wanted. template - index view determines its default columns from the template's ``tal:condition="request/show/<property>"`` directives. template - menu() and field() look awfully similar now .... ;) roundup_admin.py - the command-line tool has a lot more commands at its disposal ----------------- Back to `Table of Contents`_ .. _`Table of Contents`: index.html