maria-discuss team mailing list archive

[Justin Swanhart <greenlion@xxxxxxxxx>]

Hi,

I removed dependencies on the perfschema, I removed the `threads` table,
the queue  is now FIFO.  The queue() proc now also populates @query_list,
with queries in order as they were submitted.  You can submit a bunch of
queries then call wait_all() to wait for each submitted query, and return
results, in the order that the queries were queued.

--Justin

On Wed, Feb 24, 2016 at 11:34 AM, Justin Swanhart <greenlion@xxxxxxxxx>
wrote:

> oops, didn't copy the list.
>
> ---------- Forwarded message ----------
> From: Justin Swanhart <greenlion@xxxxxxxxx>
> Date: Wed, Feb 24, 2016 at 11:34 AM
> Subject: Re: [Maria-discuss] New Question: Non-blocking calls from PHP
> To: Federico Razzoli <federico_raz@xxxxxxxx>
>
>
> Hi,
>
> For now, if you want FIFO, just change the ORDER BY q_id DESC to ORDER BY
> q_id.  The execution is parallel, it shouldn't starve queries.  I will
> probably change this anyway by changing the structure of the `q` table to
> have a primary key that sorts by the completion status and a unique key for
> the auto_increment columns, then it can naturally be FIFO without causing
> lock contention due to locking scanned rows in InnoDB.
>
> The workaround for GET DIAGNOSTICS is to change it to not use that and
> just put a generic error in the table.  You can't use conditional version
> syntax in stored procs, and I don't want to have two different versions of
> the script, since everyone really should be using 5.6+ or MariaDB 5.5+ IMHO.
>
> I will remove count_running_threads, it isn't really needed because the
> metadata locks held by the stored proc enforce that no more than
> 'thread_count' threads can run.  I will remove that code shortly.  I wasn't
> using metadata locks when I started writing the tool.  This will remove the
> dependency on global variables and the processlist.
>
> It is version 1.0 and is still experimental :)  Thank you for the feedback.
>
> --Justin
>
> On Wed, Feb 24, 2016 at 10:58 AM, Federico Razzoli <federico_raz@xxxxxxxx>
> wrote:
>
>> Yes, GET DIAGNOSTICS is in 5.5 (and anyway, a workaround for older
>> versions should be possible, correct?).
>>
>> Some comments:
>>
>> 1) The LIFO tables sounds to me a little dangerous. Of course
>> "asynchronous" means "asynchronous", but under certain circumstances some
>> queries could wait too much... don't you agree? Maybe the direction could
>> depend from an option...
>>
>> 2) SELECT queries are "materialized", which is cool. But I don't
>> understand how the user can associate an async query with the results table.
>>
>> 3) In MariaDB, the P_S is disabled by default, and a user can still
>> disable it in MySQL. Also, in MariaDB global_status is in I_S, while MySQL
>> has it in P_S (another funny incompatibility developed by Oracle). The
>> first problem can probably be addressed with CONNECT (SRCDEF='show
>> processlist') and the second with a view in async schema. Would you accept
>> a patch?
>>
>> Probably more comments/questions will come. In the meanwhile, thanks for
>> your work (again).
>>
>> bye
>> Federico
>>
>>
>> --------------------------------------------
>> Mer 24/2/16, Justin Swanhart <greenlion@xxxxxxxxx> ha scritto:
>>
>>  Oggetto: Re: [Maria-discuss] New Question: Non-blocking calls from PHP
>>  A: "Federico Razzoli" <federico_raz@xxxxxxxx>
>>  Cc: "Maria Discuss" <maria-discuss@xxxxxxxxxxxxxxxxxxx>
>>  Data: Mercoledì 24 febbraio 2016, 16:04
>>
>>  Hi,
>>  It is
>>  completely native.  It consists of a queue table, a thread
>>  state table, a settings table, a stored procedure worker, an
>>  event to execute the worker (more than one run in parallel)
>>  and procs to drop off, check on, and get the results of a
>>  SQL statement (which always waits if the SQL is not done
>>  yet).
>>  I don't know
>>  if MariaDB 5.5 or 10 adds GET DIAGNOSTICS, but it will work
>>  with any version that has it.  You can comment that out and
>>  just put a generic error into the table if it isn't
>>  supported, and it will work with any version that has
>>  SIGNAL.
>>  --Justin
>>  On Wed, Feb 24, 2016 at
>>  10:01 AM, Federico Razzoli <federico_raz@xxxxxxxx>
>>  wrote:
>>  Hi
>>  Justin!
>>
>>  The name reminds me a a fatal trap for developers and sys
>>  admins (async npm module), but the tools sounds useful.
>>
>>  Is it publicly available? Is it entirely implemented via
>>  stored procedures + event scheduler?
>>
>>
>>
>>  bye
>>
>>  Federico
>>
>>
>>
>>
>>
>>  --------------------------------------------
>>
>>  Mer 24/2/16, Justin Swanhart <greenlion@xxxxxxxxx>
>>  ha scritto:
>>
>>
>>
>>   Oggetto: Re: [Maria-discuss] New Question: Non-blocking
>>  calls from PHP
>>
>>   A: "AskMonty KB" <noreply@xxxxxxxxxxxx>
>>
>>   Cc: "Maria Discuss" <maria-discuss@xxxxxxxxxxxxxxxxxxx>
>>
>>   Data: Mercoledì 24 febbraio 2016, 15:32
>>
>>
>>
>>   Replying
>>
>>   here in addition to the web page (ugh
>>  Frankenstein's
>>
>>   monster)...
>>
>>
>>
>>   I just finished
>>
>>   the first version of 'async' which runs queries
>>  in
>>
>>   the background (in parallel!) using a queue table, a
>>  crafty
>>
>>   stored procedure for a worker thread, and an event
>>  which
>>
>>   executes the workers.
>>
>>   http://swanhart.livejournal.com/138754.html
>>
>>
>>
>>   On Sun, Feb 21, 2016 at
>>
>>   8:55 AM, AskMonty KB <noreply@xxxxxxxxxxxx>
>>
>>   wrote:
>>
>>   Hello,
>>
>>
>>
>>
>>
>>
>>
>>   A new question has been asked in " MariaDB
>>  Connector/C
>>
>>   API Functions" by shestero. Please answer it at
>> http://mariadb.com/kb/en/non-blocking-calls-from-php/
>>
>>   as the person asking the question may not be subscribed
>>  to
>>
>>   the mailing list.
>>
>>
>>
>>
>>
>>
>>
>>   --------------------------------
>>
>>
>>
>>   I want to use non-blocking API (
>> https://mariadb.com/kb/en/mariadb/non-blocking-api-reference
>>
>>   ) from PHP.
>>
>>
>>
>>   Is it possible now?
>>
>>
>>
>>   If no, can anybody give me directions how to implement
>>  my
>>
>>   own PHP-extension in C (using Connector/C) or update
>>  the
>>
>>   existing module? I don't think it's very complex,
>>  do
>>
>>   I need to add just wraper-like implementations using
>>
>>   blocking function as samples, don't I?
>>
>>
>>
>>   --------------------------------
>>
>>
>>
>>
>>
>>
>>
>>   To view or answer this question please visit:
>> http://mariadb.com/kb/en/non-blocking-calls-from-php/
>>
>>
>>
>>
>>
>>
>>
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>>
>>
>>
>>   -----Segue allegato-----
>>
>>
>>
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