This question is asking "Is it safe?"

SQL Anywhere 12 doesn't have NODE=MIRROR, and the V12 Help describes NODE=COPY as applying only to read-only scale-out copy nodes.

However, it does seem like NODE=COPY on a V12 connection in a High Availability setup involving only primary and secondary (mirror) databases (no copy nodes) can be used to prevent a read-only connection to the mirror from reconnecting to the primary in update mode when the mirror server crashes.

In other words, if the mirror crashes, NODE=COPY prevents all those roque queries from being loaded onto the primary database.

When the mirror is restarted, and reassumes its duties as mirror, the NODE=COPY connections can be reestablished.

asked 27 Oct '13, 12:20

Breck%20Carter's gravatar image

Breck Carter
accept rate: 20%

I don't have an answer but would like to note that 12.0.1 does have NODE=MIRROR and NODE=READONLY, so your question seems to hold for 12.0.0... - cf. this doc hint from the "What's new in version 12.0.1" section:

NodeType (NODE) connection parameter enhancement The NodeType connection value now supports MIRROR and READONLY values:

  • MIRROR Redirects the application to the tenant's mirror database.
  • READONLY Redirects the application to any read-only database copy: either a copy node or the mirror copy. If there are no read-only copy nodes, READONLY is equivalent to the MIRROR setting. If there are only read-only copy nodes, READONLY is equivalent to the COPY setting.
(28 Oct '13, 05:41) Volker Barth
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question asked: 27 Oct '13, 12:20

question was seen: 545 times

last updated: 28 Oct '13, 05:48