Limiting results and paging
DSE Search integrates native driver paging with Apache Solr™ cursor-based paging. Pagination, also called cursors, supports using a cursor to scan results. Solr pagination restrictions apply.
Using paging with CQL SELECT
A CQL SELECT run by DSE Search query uses deep paging when:
| Required | One of these applies |
|---|---|
Driver is using paging |
No LIMIT is provided. |
Driver is using paging |
The number of rows to return is greater than the driver’s page size. |
Deep paging is not used if a LIMIT is provided, and the LIMIT is less than the driver’s fetch size.
Using paging with CQL Solr queries (solr_query)
|
When using CQL Solr queries with pagination enabled, your queries might experience a performance slowdown because Solr is not able to use its query result cache when pagination is configured. If you do not want to paginate through large result sets, disable pagination when running CQL Solr queries. See the driver documentation. |
In dse.yaml, the cql_solr_query_paging option specifies when to use pagination:
-
To use the driver pagination settings by default when a driver connects to the database and executes a CQL SELECT statement using a search index
solr_queryoption, set the cql_solr_query_paging todriver. -
To enable pagination persistently with CQL Solr queries, set https://docs.datastax.com/en/dse/6.8/dse-admin/datastax_enterprise/config/configDseYaml.html#configDseYamlCQLSolrPaging[cql_solr_query_paging: on] in dse.yaml and restart the node. * To dynamically enable paging when https://docs.datastax.com/en/dse/6.8/dse-admin/datastax_enterprise/config/configDseYaml.html#configDseYamlCQLSolrPaging[cql_solr_query_paging] is set to
offin dse.yaml, set the Solr paging parameter to driver ("paging":"driver"). For example:
SELECT id FROM wiki.solr
WHERE solr_query= '{"q":"*", "sort":"id asc", "paging":"driver"}' ;|
SearchAnalytics nodes always use driver paging settings. See DSE Analytics and Search integration. |
|
If cqlsh PAGING is enabled, query results display in 100-line chunks followed by the more prompt. Press the space bar to move to the next chunk. When disabled with PAGING OFF, the entire results are displayed. |
It is not mandatory to use a sort clause. However, if a sort clause is not provided, sorting is undefined.
Example of CQL SELECT query
SELECT * FROM wiki.solr WHERE id LIKE 'Journal%';
Examples of CQL Solr queries (solr_query)
The word Journal is contained in ~159 entries in the body or title.
Use count to determine the number of rows that match:
SELECT count(*) FROM wiki.solr WHERE solr_query = 'Journal';Count returns only a single row; it is not affected by the 10 row limit.
count
-------
159
(1 rows)Run the same query without count (and cql_solr_query_paging: off):
SELECT id FROM wiki.solr WHERE solr_query = 'Journal';Only 10 rows are returned.
id
----------
23759487
23732986
23759527
23759551
23759455
23760810
23731949
23760697
23760871
23738270
(10 rows)To return all matching IDs, override the cql_solr_query_paging setting:
SELECT id FROM wiki.solr
WHERE solr_query='{"q":"Journal", "paging":"driver"}';