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There is an important side effect. While you would expect the parent table retention
period to age out old micro-partitions, you find the retained micro-partitions allow
UNDROP
operations, leading to the recovery of the
partsupp_baseline
table.
UNDROP TABLE tpc.tpc_owner.partsupp_baseline;
While I would not choose to rely upon unexpected micro-partition retention to
UNDROP
objects, I suggest this action may be possible and should not be discounted.
Simply put, you cannot determine whether
UNDROP
will work until you try, and an
attempt to
UNDROP
has a temporal component.
Data Sharing and Replication
Data sharing within the same CSP and region is implemented by sharing micro-
partitions with consumers via Secure Direct Data Share, Private Listings, or Snowflake
Marketplace. Consumers ingesting shared data reference current micro-partitions only;
they see data producer transactions in real time at zero cost. Consumers cannot see any
historical transactions, nor can they access Time Travel or Fail-Safe for the producer
account.
Replication is implemented by shipping changed micro-partitions to consuming
accounts using either database replication or account replication. Ingesting replicated
micro-partitions requires replication to be configured, which is a timed refresh event and
therefore not real time.
A full investigation of data sharing and replication is beyond the scope of this book
and is worthy of a significant chapter on its own, which I delivered in my previous book,
Maturing the Snowflake Data Cloud.
You can find more information at
https://docs.snowflake.com/en/guides-
overview-sharing
.
Micro-partitions End to End
Throughout this chapter you have worked through how micro-partitions are both
expected and observed to transition from active through Time Travel and Fail-Safe and
then removal while also considering cloning.
You also investigated how the data retention period and Account Usage Store
latency affects observability of transitions across each state. You also learned there are
ChaPTer 4
MiCro-ParTiTionS