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Re: doubts about show ___ any information table plugin


Hi, Roberto!

On Oct 17, Roberto Spadim wrote:
> i was reading this:
> https://mariadb.com/kb/en/information-schema-plugins-show-and-flush-statements/
> and i'm with some doubts...
> automatically parser translate "_" to space? for example table A_B, i could
> use SHOW A B ?

yeah, I thought about it. I would look nice, surely.
But I don't believe bison generated parser can handle this, it doesn't
really support dynamically changing grammar.

> about the FLUSH
> what it does? any example of what it should do? like... i know we can reset
> some information counters, it's a 'shortcut' to avoid something like "SET
> pluginvariable=0"? if yes, maybe we could add some example at KB page, i'm
> with doubts, maybe a dba without knowledge about plugin internal will not
> understand

Yes, it's useful to reset statistics that information schema plugin
shows. See examples in query_response_time plugin and in userstat

Old way of doing the same was to have a special
variable, like in query_response_time plugin in 10.0:

  set @@query_response_time_flush=1;

but it was kind of a hack, query_response_time_flush was not really a
variable, its value was useless, for example. And it was not behaving as
a user intuitively expects it to. Now one can write

  flush query_response_time;

which is much more logical and intuitively expected.