pythonpaginationcassandracqlcqlengine

DataStax Enterprise 4.6.1 / C* Pagination in Python using cqlengine 0.21.0

I am currently trying to paginate query results from DSE 4.6.1 (Cassandra 2.0.12.200) with Python and cqlengine 0.21.0.

My table being queried is:

CREATE TABLE tags_for_search (
  village_id int,
  tag_prefix text,
  tag text,
  time timeuuid,
  author_id int,
  tag_id uuid,
  type text,
  PRIMARY KEY ((village_id, tag_prefix), tag, time)
) WITH CLUSTERING ORDER BY (time DESC) AND
  bloom_filter_fp_chance=0.010000 AND
  caching='KEYS_ONLY' AND
  comment='' AND
  dclocal_read_repair_chance=0.100000 AND
  gc_grace_seconds=864000 AND
  index_interval=128 AND
  read_repair_chance=0.000000 AND
  populate_io_cache_on_flush='false' AND
  default_time_to_live=0 AND
  speculative_retry='99.0PERCENTILE' AND
  memtable_flush_period_in_ms=0 AND
  compaction={'class': 'SizeTieredCompactionStrategy'} AND
  compression={'sstable_compression': 'LZ4Compressor'};

Is there an alternative for paging/pagination (DataStax Enterprise / DSE 4.6.1) of results in Python (using cqlengine 0.21.0)? The documented solution (http://cqlengine.readthedocs.org/en/latest/topics/queryset.html#token-function) appears to be broken due to #7016.

My initial query for data is:

SELECT * FROM that_keyspace.tags_for_search WHERE "tag_prefix" = 'der' AND "tag_text" = '#derpy1' AND "village_id" = 1 LIMIT 10000;

Or in Python via cqlengine:

village_tags = VillageSearch.objects.filter(village_id=1, tag_prefix='der', tag_text='#derpy1')

tags_data = []
for village_tag in village_tags:
    tags_data.append(village_tag.to_dict())

first_page = village_tags
last = first_page[-1]
next_page = list(village_tags.filter(pk__token__gt=cqlengine.Token(last.pk)))

It is throwing the error:

code=2200 [Invalid query] message="Column "village_id" cannot be restricted by both an equality and an inequality relation"

Is there an alternative that I can use to avoid this bug for immediate usage?

Thank you for any assistance you are able to provide!

Solution

  • There isn't a direct replacement for this functionality. The best and most appropriate answer is to upgrade (now that this bug fix is available).

    Upgrading your environment to DSE >= 4.6.2 will resolve this issue.