[Firebird-website] [FB-Tracker] Updated: (WEB-131) gfix -write sync documentation is wrong

[Коренберг М. (J. <tr...@fi...>]

     [ http://tracker.firebirdsql.org/browse/WEB-131?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Коренберг Марк updated WEB-131:
-------------------------------

    Description: 
http://www.firebirdsql.org/manual/gfix-sync.html

gfix -write sync states that: "sync - data is written synchronously. This means that data is flushed to disc on COMMIT."

THIS IS WRONG, since in current implemetation (FB 2.5 in Linux) it just opens file using O_SYNC. This mean that every write is synchronous. Not only at COMMIT. So this is major performance loss.

So, what I want:
1. Fix documentation and say, that "gfix -write sync" will synchronously wait for every write fo file.
(Also, I'm not sure it is the same as forcedwrites=ON)
2. Add to documentation something like this:
"""
In order to bring performance/integrity to reasonable state, you may do that:
gfix -write async
Forced writes=off
MaxUnflushedWrites = 0
MaxUnflushedWriteTime = -1
"""
(As far as I see in strace, it issues fsync() at every commit at least.)

  was:
http://www.firebirdsql.org/manual/gfix-sync.html

gfix -write sync states that: "sync - data is written synchronously. This means that data is flushed to disc on COMMIT."

THIS IS WRONG, since in current implemetation (FB 2.5 in Linux) it just opens file using O_SYNC. This mean that every write is synchronous. Not only at COMMIT. So this is major performance loss.

In order to bring performance/integrity to reasonable state, you may do that:



So, what I want:
1. Fix documentation and say, that "gfix -write sync" will synchronously wait for every write fo file.
(Also, I'm not sure it is the same as forcedwrites=ON)
2. Add to documentation:
"""
gfix -write async
Forced writes=off
MaxUnflushedWrites = 0
MaxUnflushedWriteTime = -1
"""
(As far as I see in strace, it issues fsync() at every commit at least.)


> gfix -write sync documentation is wrong
> ---------------------------------------
>
>                 Key: WEB-131
>                 URL: http://tracker.firebirdsql.org/browse/WEB-131
>             Project: Web site
>          Issue Type: Bug
>         Environment: Firebird 2.5
>            Reporter: Коренберг Марк
>            Assignee: Alexey Kovyazin
>
> http://www.firebirdsql.org/manual/gfix-sync.html
> gfix -write sync states that: "sync - data is written synchronously. This means that data is flushed to disc on COMMIT."
> THIS IS WRONG, since in current implemetation (FB 2.5 in Linux) it just opens file using O_SYNC. This mean that every write is synchronous. Not only at COMMIT. So this is major performance loss.
> So, what I want:
> 1. Fix documentation and say, that "gfix -write sync" will synchronously wait for every write fo file.
> (Also, I'm not sure it is the same as forcedwrites=ON)
> 2. Add to documentation something like this:
> """
> In order to bring performance/integrity to reasonable state, you may do that:
> gfix -write async
> Forced writes=off
> MaxUnflushedWrites = 0
> MaxUnflushedWriteTime = -1
> """
> (As far as I see in strace, it issues fsync() at every commit at least.)

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