Hi,
The thing is that the PK index is currently created roughly as
CREATE INDEX T(_key)
and not
CREATE INDEX T(customer_id, date).
You can’t use the _key column in the WHERE clause directly, so the query
optimizer can’t use the index.
After the IGNITE-8386 is fixed the index will be created as a multi-column
index, and will behave the way you expect (e.g. it will be used instead of the
affinity key index).
Stan
From: eugene miretsky
Sent: 12 сентября 2018 г. 23:45
To: user@ignite.apache.org
Subject: IGNITE-8386 question (composite pKeys)
Hi,
A question regarding
https://issues.apache.org/jira/browse/IGNITE-8386?focusedCommentId=16511394&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16511394
It states that a pkey index with a compoise pKey is "effectively useless".
Could you please explain why is that? We have a pKey that we are using as an
index.
Also, on our pKey is (customer_id, date) and affinity column is customer_id. I
have noticed that most queries use AFFINITY_KEY index. Looking at the source
code, AFFINITY_KEY index should not even be created since the first field of
the pKey is the affinity key. Any idea what may be happening?
Cheers,
Eugene
