Tanuj Khurana created PHOENIX-8016:
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Summary: Uncovered-index read-repair never deletes a stale index
entry when the data row is actively updated
Key: PHOENIX-8016
URL: https://issues.apache.org/jira/browse/PHOENIX-8016
Project: Phoenix
Issue Type: Bug
Affects Versions: 5.3.2, 5.3.1, 5.2.2, 5.3.0, 5.2.1, 5.2.0
Reporter: Tanuj Khurana
Orphaned/stale uncovered-index entries (e.g. a NULL-keyed entry left behind
after
a row's indexed value changes from NULL to non-null) are supposed to be cleaned
by
lazy read-repair, but for an actively-updated data row they are *never* deleted,
no matter how old the stale index cell is.
Read-repair for uncovered indexes runs on the read path in
{{UncoveredIndexRegionScanner.verifyIndexRowAndRepairIfNecessary}} (:321-362)
and
the {{dataRow == null}} branch of {{getNextCoveredIndexRow}} (:384-393), gated
on
{{ageThreshold}} ({{phoenix.global.index.row.age.threshold.to.delete.ms}},
default 7 days, {{QueryServicesOptions.java:439-440}}).
A stale (but non-orphan) entry hits the "data row exists but index row is stale"
case (:353-360). The tenant's data row still exists (now with a non-null indexed
value), so {{checkIndexRow}} fails, and the delete is gated on *the data row's*
max timestamp:
{code:java}
if (indexMaintainer.isAgedEnough(IndexUtil.getMaxTimestamp(put), ageThreshold)
...) { // :354
region.delete(indexMaintainer.createDelete(indexRowKey,
IndexUtil.getMaxTimestamp(put), false));
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