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During the writing of this chapter, observing transitions between the differing layers
of storage has not proven to be straightforward. I assume Snowflake does not run its
processes to transition micro-partitions with high frequency and speculate its processes
may execute at least once within the 90-minute view latency period. As a consequence, I
did not experience a consistent up-to-the minute timeline for observing micro-partition
transitions across storage layers; rather, the timeline was somewhat variable.
Your testing may be impacted if conducted over several days.
To illustrate time sensitivity, let’s examine an idealized scenario and timeline, as
represented in Figure 4-5.
Figure 4-5.
Expected storage timeline with latency
Here’s a breakdown of Figure 4-5:
1.
Day 1: At 08:00 you assume a table is created with the data
retention period set to one day.
2.
Day 1: At 09:30 view latency is complete, storage is visible, and
then the table is dropped.
3.
Day 2: At 09:30 the dropped table storage moves to Time Travel for
one day, and the view has 90 minutes of latency.
4.
Day 2: At 11:00 the view latency is complete, and Time Travel
storage is visible.
5.
Day 3: At 09:30 the dropped table storage moves to Fail-Safe for
seven days, and the view has 90 minutes of latency.
6.
Day 3: At 11:00 the view latency is complete, and Fail-Safe storage
is visible.
ChaPTer 4
MiCro-ParTiTionS