Thread: Fast Table Replication / Mirroring

Fast Table Replication / Mirroring

From
Alex
Date:
Hi,
I saw some replication projects but think this might be an overkill for
my intentions.

I have two databases, Primary / Secondary where the Secondary is
readyonly for
users. I need to mirror tables when changes occur on that table. That
may happen a few times a day.
Tables are in the area of  few 100k records.

A) Is there an easy way to copy the data from Primary to Secondary
     Can this be triggered by updates on the primary table ?

B) Is there a fast way to check if table A on Primary and Secondary
server are in Sync?
     Not number of records but contents.

Any advise would be appreciated.

Alex



Re: Fast Table Replication / Mirroring

From
"Gregory S. Williamson"
Date:
see contrib/dbmirror ... triggered by updates on the primary. Don't know if it would work for you ... not sure about
thesecond part (see the differences). It uses a table it creates called "Pending" to store transactions. 

Greg W.

-----Original Message-----
From:    Alex [mailto:alex@meerkatsoft.com]
Sent:    Thu 8/28/2003 8:49 PM
To:    pgsql-general@postgresql.org
Cc:
Subject:    [GENERAL] Fast Table Replication / Mirroring

Hi,
I saw some replication projects but think this might be an overkill for
my intentions.

I have two databases, Primary / Secondary where the Secondary is
readyonly for
users. I need to mirror tables when changes occur on that table. That
may happen a few times a day.
Tables are in the area of  few 100k records.

A) Is there an easy way to copy the data from Primary to Secondary
     Can this be triggered by updates on the primary table ?

B) Is there a fast way to check if table A on Primary and Secondary
server are in Sync?
     Not number of records but contents.

Any advise would be appreciated.

Alex



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Re: Fast Table Replication / Mirroring

From
Alex
Date:
Marc,
could you point me to some information on eRServer ? Ist this a
commercial product ?

Thanks
A

Marc G. Fournier wrote:

>On Fri, 29 Aug 2003, Alex wrote:
>
>
>
>>Hi,
>>I saw some replication projects but think this might be an overkill for
>>my intentions.
>>
>>I have two databases, Primary / Secondary where the Secondary is
>>readyonly for
>>users. I need to mirror tables when changes occur on that table. That
>>may happen a few times a day.
>>Tables are in the area of  few 100k records.
>>
>>A) Is there an easy way to copy the data from Primary to Secondary
>>     Can this be triggered by updates on the primary table ?
>>
>>
>
>We're actually using eRServer inhouse for this, to keep "local copies" of
>on specific table in sync between several servers ...
>
>
>
>
>



Re: Fast Table Replication / Mirroring

From
"Marc G. Fournier"
Date:

On Fri, 29 Aug 2003, Alex wrote:

> Hi,
> I saw some replication projects but think this might be an overkill for
> my intentions.
>
> I have two databases, Primary / Secondary where the Secondary is
> readyonly for
> users. I need to mirror tables when changes occur on that table. That
> may happen a few times a day.
> Tables are in the area of  few 100k records.
>
> A) Is there an easy way to copy the data from Primary to Secondary
>      Can this be triggered by updates on the primary table ?

We're actually using eRServer inhouse for this, to keep "local copies" of
on specific table in sync between several servers ...


Re: Fast Table Replication / Mirroring

From
"Marc G. Fournier"
Date:
Yes and no ... we just released an OSS version of it on gborg, based on
v1.2 ...

    http://gborg.postgresql.org/project/erserver/projdisplay.php


On Fri, 29 Aug 2003, Alex wrote:

> Marc,
> could you point me to some information on eRServer ? Ist this a
> commercial product ?
>
> Thanks
> A
>
> Marc G. Fournier wrote:
>
> >On Fri, 29 Aug 2003, Alex wrote:
> >
> >
> >
> >>Hi,
> >>I saw some replication projects but think this might be an overkill for
> >>my intentions.
> >>
> >>I have two databases, Primary / Secondary where the Secondary is
> >>readyonly for
> >>users. I need to mirror tables when changes occur on that table. That
> >>may happen a few times a day.
> >>Tables are in the area of  few 100k records.
> >>
> >>A) Is there an easy way to copy the data from Primary to Secondary
> >>     Can this be triggered by updates on the primary table ?
> >>
> >>
> >
> >We're actually using eRServer inhouse for this, to keep "local copies" of
> >on specific table in sync between several servers ...
> >
> >
> >
> >
> >
>
>
>

Re: Fast Table Replication / Mirroring

From
Ron Johnson
Date:
On Thu, 2003-08-28 at 22:49, Alex wrote:
> Hi,
> I saw some replication projects but think this might be an overkill for
> my intentions.
>
> I have two databases, Primary / Secondary where the Secondary is
> readyonly for
> users. I need to mirror tables when changes occur on that table. That
> may happen a few times a day.
> Tables are in the area of  few 100k records.
>
> A) Is there an easy way to copy the data from Primary to Secondary
>      Can this be triggered by updates on the primary table ?
>
> B) Is there a fast way to check if table A on Primary and Secondary
> server are in Sync?
>      Not number of records but contents.

If changes only happens a couple of times a day, and the table only
have a few hundred thousand rows in them, why not dump the tables
every few hours and load them into the Secondary DB?

--
-----------------------------------------------------------------
Ron Johnson, Jr. ron.l.johnson@cox.net
Jefferson, LA USA

"they love our milk and honey, but preach about another way of living"
Merle Haggard, "The Fighting Side Of Me"


Re: Fast Table Replication / Mirroring

From
Alex
Date:
I need to reflect the changes onto the secondary machine and would like
to initiate and run the process from the primary machine. The secondary
machine may be in use at the time (read only though) and I cannot
truncate or drop tables there (also because I have foreign key
constraints on the table itself).



Ron Johnson wrote:

>On Thu, 2003-08-28 at 22:49, Alex wrote:
>
>
>>Hi,
>>I saw some replication projects but think this might be an overkill for
>>my intentions.
>>
>>I have two databases, Primary / Secondary where the Secondary is
>>readyonly for
>>users. I need to mirror tables when changes occur on that table. That
>>may happen a few times a day.
>>Tables are in the area of  few 100k records.
>>
>>A) Is there an easy way to copy the data from Primary to Secondary
>>     Can this be triggered by updates on the primary table ?
>>
>>B) Is there a fast way to check if table A on Primary and Secondary
>>server are in Sync?
>>     Not number of records but contents.
>>
>>
>
>If changes only happens a couple of times a day, and the table only
>have a few hundred thousand rows in them, why not dump the tables
>every few hours and load them into the Secondary DB?
>
>
>