Delete spatiotemporal objects

Choose a deletion method

Delete by TTL

Lindorm GanosBase uses the Time to Live (TTL) feature of ApsaraDB for HBase to automatically expire data. You can use HBase Shell to modify the TTL attribute of the spatio-temporal index table to delete expired data.

If multiple index tables exist, set TTL on each table separately. The TTL value is in seconds.

Example: Delete data older than 5 minutes (300 seconds) from a spatio-temporal index table xxx_z3 and an attribute index table xxx_attr:

Alter 'xxx_z3',{NAME=>'d',TTL=>300}
Alter 'xxx_attr',{NAME=>'d',TTL=>300}

Delete by spatio-temporal range

This method applies only to z2/xz2 and z3/xz3 spatio-temporal index tables.

Procedure:

1. Configure a filter to identify the objects to delete. Use the same filter syntax as for queries — the filter string must comply with Extended Common Query Language (ECQL) syntax.

2. Call SimpleFeatureStore.removeFeatures() from GeoTools to delete matching objects.

/**
 * Delete spatio-temporal objects that match the specified filter.
 * @param schema       the schema name
 * @param filterString the ECQL filter string; if blank, all objects are deleted
 */
public void removeByFilter(String schema, String filterString) throws Exception {
    SimpleFeatureStore fs = (SimpleFeatureStore) ds.getFeatureSource(schema);
    // If filterString is blank, all spatio-temporal objects are deleted.
    if (StringUtils.isEmpty(filterString)) {
        fs.removeFeatures(Filter.INCLUDE);
        return;
    }
    Filter filterToDelete = ECQL.toFilter(filterString);
    fs.removeFeatures(filterToDelete);
}

Delete by object ID

This method deletes data only from the index table associated with the specified ID. Data in other index tables is not affected.

Call SimpleFeatureStore.removeFeatures() with an ID filter built using FilterFactory2:

public void removeById(String schema, String simpleFeatureId) throws Exception {
    // Build an ID filter using FilterFactory2.
    FilterFactory2 ff = CommonFactoryFinder.getFilterFactory2();
    Filter filterToDelete = ff.id(ff.featureId(simpleFeatureId));
    SimpleFeatureStore fs = (SimpleFeatureStore) ds.getFeatureSource(schema);
    fs.removeFeatures(filterToDelete);
}