[CASSANDRA-5540] Concurrent secondary index updates remove rows from the index

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.2.5
• Component/s: Feature/2i Index
• Severity: Normal
• Assignee: Sam Tunnicliffe
• Reporter: Alexei Bakanov

Authors

Sam Tunnicliffe

Reviewers

Jonathan Ellis

• Created: 06/May/13 11:04
• Updated: 16/Apr/19 09:32
• Resolved: 09/May/13 22:42

Description

Existing rows disappear from secondary index when doing simultaneous updates of a row with the same secondary index value.

Here is a little pycassa script that reproduces a bug. The script inserts 4 rows with same secondary index value, reads those rows back and check that there are 4 of them.
Please run two instances of the script simultaneously in two separate terminals in order to simulate concurrent updates:

-----scrpit.py START-----
import pycassa
from pycassa.index import *

pool = pycassa.ConnectionPool('ks123')
cf = pycassa.ColumnFamily(pool, 'cf1')

while True:
    for rowKey in xrange(4):
        cf.insert(str(rowKey), {'indexedColumn': 'indexedValue'})

    index_expression = create_index_expression('indexedColumn', 'indexedValue')
    index_clause = create_index_clause([index_expression])
    rows = cf.get_indexed_slices(index_clause)
    length = len(list(rows))
    if length == 4:
        pass
    else:
        print 'found just %d rows out of 4' % length

pool.dispose()

---script.py FINISH---

---schema cli start---
create keyspace ks123
  with placement_strategy = 'NetworkTopologyStrategy'
  and strategy_options = {datacenter1 : 1}
  and durable_writes = true;

use ks123;

create column family cf1
  with column_type = 'Standard'
  and comparator = 'AsciiType'
  and default_validation_class = 'AsciiType'
  and key_validation_class = 'AsciiType'
  and read_repair_chance = 0.1
  and dclocal_read_repair_chance = 0.0
  and populate_io_cache_on_flush = false
  and gc_grace = 864000
  and min_compaction_threshold = 4
  and max_compaction_threshold = 32
  and replicate_on_write = true
  and compaction_strategy = 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'
  and caching = 'KEYS_ONLY'
  and column_metadata = [
    {column_name : 'indexedColumn',
    validation_class : AsciiType,
    index_name : 'INDEX1',
    index_type : 0}]
  and compression_options = {'sstable_compression' : 'org.apache.cassandra.io.compress.SnappyCompressor'};
---schema cli finish---

Test cluster created with 'ccm create --cassandra-version 1.2.4 --nodes 1 --start testUpdate'