[CASSANDRA-286] slice offset breaks read repair

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 0.4
• Severity: Normal
• Assignee: Jonathan Ellis
• Reporter: Jonathan Ellis

Authors

Jonathan Ellis

• Created: 09/Jul/09 14:26
• Updated: 16/Apr/19 09:33
• Resolved: 16/Jul/09 00:39

Description

[code]
int liveColumns = 0;
int limit = offset + count;

for (IColumn column : reducedColumns)

{ if (liveColumns >= limit) break; if (!finish.isEmpty() && ((isAscending && column.name().compareTo(finish) > 0)) || (!isAscending && column.name().compareTo(finish) < 0)) break; if (!column.isMarkedForDelete()) liveColumns++; if (liveColumns > offset) returnCF.addColumn(column); }

[code]

The problem is that for offset to return the correct "live" columns, it has to ignore tombstones it scans before the first live one post-offset.

This means that instead of being corrected within a few ms of a read, a node can continue returning deleted data indefinitely (until the next anti-entropy pass).

Coupled with offset's inherent inefficiency (see CASSANDRA-261) I think this means we should take it out and leave offset to be computed client-side (which, for datasets under which it was reasonable server-side, will still be reasonable).