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Figure 3: Partitioned Data in Buckets
If you set the redundant-copies for the table to be greater than zero, SQLFire designates one of the copies of
each bucket as the primary copy. All writes to the bucket go through the primary copy. This ensures that all
copies of the bucket are consistent.
The Group Membership Service (GMS) and distributed locking service ensure that all distributed members have
a consistent view of primaries and secondaries at any moment in time across the distributed system, regardless
of membership changes initiated by the administrator or by failures.
Failure and Redundancy
If you have redundant copies of a partitioned table, you can lose servers without loss of data or interruption of
service. When a server fails, SQLFire automatically re-routes any operations that were trying to read or write
from the failed member to the surviving members.
In this figure, M1 is reading table values W and Y. It reads W directly from its local copy and attempts to read
Y from M3, which is offline. The read is automatically retried in another available member.
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Partitioning Tables