7:46 a.m.
Hi,
I haev a quick question which I haven't been able to find an answer to
in the docs:
I have a slapd master with a couple of slaves (syncrepl
refreshAndPersist). I can get updates to be diverted to the master with
the chain overlay, but as the FAQ says there'll be a small delay before
the changes are replicated back to the slaves.
Is there anyway to automatically direct subsequent reads of the changed
attributes to the master?
Else I guess I'll have to implement referral chasing logic in the client
so it doesn't try to read from the slave immediately after writing (and
getting a referral).
regards,
Peter
9 a.m.
Peter Mogensen wrote:
Hi,
I haev a quick question which I haven't been able to find an answer to
in the docs:
I have a slapd master with a couple of slaves (syncrepl
refreshAndPersist). I can get updates to be diverted to the master with
the chain overlay, but as the FAQ says there'll be a small delay before
the changes are replicated back to the slaves.
Is there anyway to automatically direct subsequent reads of the changed
attributes to the master?
If you have access to the master why not just write to the master to
begin with?
Else I guess I'll have to implement referral chasing logic in the client
so it doesn't try to read from the slave immediately after writing (and
getting a referral).
regards,
Peter
--
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Gavin Henry.
Managing Director.
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11:12 a.m.
Gavin Henry wrote:
If you have access to the master why not just write to the master to
begin with?
Because it would make the clients and their configuration a fair bit
more complex. I'd rather not know the identity of the master server in
the client code if I could avoid it.
Peter
9:23 a.m.
Peter Mogensen wrote:
I haev a quick question which I haven't been able to find an
answer to
in the docs:
I have a slapd master with a couple of slaves (syncrepl
refreshAndPersist). I can get updates to be diverted to the master with
the chain overlay, but as the FAQ says there'll be a small delay before
the changes are replicated back to the slaves.
Is there anyway to automatically direct subsequent reads of the changed
attributes to the master?
Yes, there is: add the "don't use copy" control to the read request. If
your client has write, then read requirements, using the chain overlay
to avoid dealing with referrals is definitely a bad idea.
p.
Ing. Pierangelo Masarati
OpenLDAP Core Team
SysNet s.r.l.
via Dossi, 8 - 27100 Pavia - ITALIA
http://www.sys-net.it
---------------------------------------
Office: +39 02 23998309
Mobile: +39 333 4963172
Email: pierangelo.masarati(a)sys-net.it
---------------------------------------
11:15 a.m.
Pierangelo Masarati wrote:
Yes, there is: add the "don't use copy" control to the
read request. If
your client has write, then read requirements, using the chain overlay
to avoid dealing with referrals is definitely a bad idea.
Ah... "don't use copy" is slapd 2.4. I forgot to say I'm on 2.3 - for
now.
Anyway... I thought that was the whole point of slapo-chain - to get
automatic referral chasing.
regards,
Peter
11:53 a.m.
Peter Mogensen wrote:
Pierangelo Masarati wrote:
> Yes, there is: add the "don't use copy" control to the read request.
If
> your client has write, then read requirements, using the chain overlay
> to avoid dealing with referrals is definitely a bad idea.
Ah... "don't use copy" is slapd 2.4. I forgot to say I'm on 2.3 - for
now.
Anyway... I thought that was the whole point of slapo-chain - to get
automatic referral chasing.
It is. But if a client knows it's doing something weird (like write,
then read, potentially to a consumer) then it needs to take precautions,
like don't use copy. In that case, the consumer would return a
referral, and slapo-chain would chase it transparently.
p.
Ing. Pierangelo Masarati
OpenLDAP Core Team
SysNet s.r.l.
via Dossi, 8 - 27100 Pavia - ITALIA
http://www.sys-net.it
---------------------------------------
Office: +39 02 23998309
Mobile: +39 333 4963172
Email: pierangelo.masarati(a)sys-net.it
---------------------------------------
12:02 p.m.
Pierangelo Masarati wrote:
Peter Mogensen wrote:
> Ah... "don't use copy" is slapd 2.4. I forgot to say I'm on 2.3 -
for now.
> Anyway... I thought that was the whole point of slapo-chain - to get
> automatic referral chasing.
It is. But if a client knows it's doing something weird (like write,
then read, potentially to a consumer) then it needs to take precautions,
like don't use copy. In that case, the consumer would return a
referral, and slapo-chain would chase it transparently.
ah... Fair enough. I see what you meant now. That would also be ok. A
lot better for me than handling database connections to the master.
Unfortunately that seems to imply a move to slapd 2.4.
Thanks for the input.
Peter
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6 comments
3 participants
participants (3)
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Gavin Henry -
Peter Mogensen -
Pierangelo Masarati