Alexander Belyak created IGNITE-14846:
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Summary: Default statistics
Key: IGNITE-14846
URL: https://issues.apache.org/jira/browse/IGNITE-14846
Project: Ignite
Issue Type: Improvement
Components: sql
Reporter: Alexander Belyak
To simplify optimizer and to get a little bit more accurate estimation Ignite
can generate some default statistics for each table (each column and so on)
based on tables metadata. For example:
boolean non null field can produce a following statistics:
min: false
max: true
nulls: 0
distinct: 2
total: <table_size>
while
uuid nullable column can produce:
min: 00-00-00-00...
max: FF-FF-FF-...
nulls: <table_size> * 0.1
distinct: <table_size> * 0.5
total: <table size>
It can be generated on the fly by statistics subsystem (and cached for future
usages).
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