Darrel Schneider created GEODE-1672:
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Summary: When amount of overflowed persisted data exceeds heap
size startup may run out of memory
Key: GEODE-1672
URL: https://issues.apache.org/jira/browse/GEODE-1672
Project: Geode
Issue Type: Bug
Components: persistence
Reporter: Darrel Schneider
Basically, when the amount of data overflowed approaches the heap size, ,such
that the total amount of data is very close to or actually surpasses your total
tenured heap, it is possible that you will not be able to restart.
The algorithm during recovery of oplogs/buckets is such that we don't "evict"
in the normal sense as data fills the heap during early stages of recovery
prior to creating the regions. When the data is first created in the heap, it's
not yet official in the region.
At any rate, if during this early phase of recovery, or during subsequent phase
where eviction is working as usual, it is possible that the total data or an
early imbalance of buckets prior to the opportunity to rebalance causes us to
surpass the critical threshold which will kill us before successful startup.
To reproduce, you could have 1 region with tons of data that evicts and
overflows with persistence. Call it R1. Then another region with persistence
that does not evict. Call it R2.
List R1 fist in the cache.xml file. Start running the system and add data over
time until you have overflowed tons of data approaching the heap size in the
evicted region, and also have enough data in the R2 region.
Once you fill these regions with enough data and have overflowed enough to disk
and persisted the other region, then shutdown, and then attempt to restart. If
you put enough data in, you will hit the critical threshold before being able
to complete startup.
You can work around this issue by configuring geode to not recovery values by
setting this system property: -Dgemfire.disk.recoverValues=false
Values will not be faulted into memory until a read operation is done on that
value's key.
If you have regions that do not use overflow and some that do then another work
around is the create the regions that do not use overflow first.
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