Re: [Firebird-devel] Power efficient userspace waiting with the umwait x86 instructions

[Ann Harrison]

> On Sep 16, 2019, at 7:50 AM, Roman Simakov  wrote:
> 
> Hi,
> 
> I guess it would be interesting alternative for spinlock
> (https://kernelnewbies.org/Linux_5.3)
> 1.6. Power efficient userspace waiting with the umwait x86 instructions
> 
> More description is here:
> https://lwn.net/Articles/790920/
> 

Spinlocks in userspace are a performance disaster - here are some rhoughts from 
Jim Starkey ...

Spin locks were invented at DEC for use in either the RSX-11M+ or VMS kernel 
for a very specific and narrow purpose.  Spin locks were used when the OS was 
initiating a very short device request where the expected completion time was 
less than the overhead to setup for and process a device interrupt.  They were 
used sparingly and effectively.

For virtually any other purpose, spin locks are a huge net loss for a very 
simple reason: Hogging the processor waiting for another thread or process not 
only wastes processor cycles but a quite likely to present the other process 
and thread from running and releasing whatever resource had induced the spin.

The last great performance leap on the Falcon/InnoDB race at MySQL was when 
Google replaced InnoDB's spin locks with Falcon's user mode synchronization 
locks, giving InnoDB a 20% or 30% kick under heavy load.

Long (or indeterminate) locks are best handled with user mode read/write 
synchronization objects.  Very short term locks can be avoided through 
judicious use of non-interlocked data structures managed with compare-and-swap. 
 AmorphousDB, for example, uses non-interlocked hash tables for things like 
transactions and network operation tickets; objects in these hash tables can be 
safely removed by first moving them into an object purgatory that is safely 
emptied by a cycle manager once a second (or whatever).

There is an incredible among of non-sense written about spin locks by folks who 
tend to believe that any technique used by and OS kernel must be very cool and 
very efficient.

The related idea of an instruction that can stall a processor waiting on memory 
write is every bit as flawed as spin locks even if it does reduce the amount of 
power consumed while gumming up the OS scheduler.

-- 
Jim Starkey


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[Firebird-devel] ODP: How to fb 3.0.4 embedde in android with delphi 10.2

[Karol Bieniaszewski]

Hi

First you must download fixed version of Firebird (current one on the official 
page is not working properly).
Look into http://tracker.firebirdsql.org/browse/CORE-5888.
There is a link for fixed version provided by Alexander Peshkov.

Look if it is working for you.

Regards,
Karol Bieniaszewski

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Re: [Firebird-devel] How to fb 3.0.4 embedde in android with delphi 10.2

[Paul Beach]

>

I don't know about Android, but Windows and Linux

https://www.ibphoenix.com/files/Embedded_fb3.pdf

MacOSX

http://paulbeachsblog.blogspot.com/2019/09/firebird-3-embedded-on-macosx.html

Regards
Paul



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[Firebird-devel] How to fb 3.0.4 embedde in android with delphi 10.2

[Geferson Dietze]

Hello. After researching a lot about this, including some topics here on
the list, I realize that many people are interested in this issue but find
it very difficult to make it work.
.
https://groups.yahoo.com/neo/groups/firebird-support/conversations/topics/131979

.
Could anyone explain in detail how to create a embedde FB 3 server on
android so people could test and build applications to test the tool?
.
Thanks
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[Firebird-devel] [FB-Tracker] Created: (CORE-6145) Wrong result in "similar to" with non latin characters

[Alex Bekhtin (JIRA)]

Wrong result in "similar to" with non latin characters
--

 Key: CORE-6145
 URL: http://tracker.firebirdsql.org/browse/CORE-6145
 Project: Firebird Core
  Issue Type: Bug
  Components: Charsets/Collation
Affects Versions: 4.0 Beta 2
Reporter: Alex Bekhtin


select * from rdb$database where 'Я' similar to '%Я%'

FB 3.0 - 1 line
FB 4.0 - 0 lines

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Re: [Firebird-devel] TIME WITH TZ

[Dimitry Sibiryakov]

18.09.2019 12:11, Alex Peshkoff via Firebird-devel wrote:
  For these API function to be useful, they must return localized region names according 
to current OS settings. I don't think that it is doable in Firebird client API.


May be they should use current connection charset?


  Traditionally conversion functions are connection-less.


--
  WBR, SD.


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Re: [Firebird-devel] TIME WITH TZ

[Dimitry Sibiryakov]

18.09.2019 3:13, Adriano dos Santos Fernandes wrote:

On 16/09/2019 08:21, Alex Peshkoff via Firebird-devel wrote:

On 16.09.2019 14:02, Adriano dos Santos Fernandes wrote:


There should be a way to client request additional data (tz offset, tz
region as string, string length) to be returned together with the data.
A general solution, not a wrong specific/incomplete solution.

OK, that's not bad.
But on what level? SQL or API? (I.e. should it be function:


API.



  For these API function to be useful, they must return localized region names according 
to current OS settings. I don't think that it is doable in Firebird client API.



--
  WBR, SD.


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