Note this trick can only be applied to indexed columns. In fact, part of the preparation for DR2 has been the identification, creation and indexation of the most common derived quantities to be used in queries. In both cases, the improvement has been obtained through the use of a pre-existing indexed column: bp_rp and parallax_over_error. Similarly, this query now returns 2892 rows Let's see how two queries in the previous section can be rewritten to improve efficiency One common trick is to use indexed fields when possible. The same would apply to a selection of very blue stars (BP – RP 1000)Īlternative formulations will be provided in the following sections for all these queries. This operation is too costly and prevents the request from being completed. This query will most probably time out because it requires computing a complex quantity, the total proper motion, for all rows in the table. Where the proper motion units in gaia_source are mas/yr. Where sqrt(pmra * pmra + pmdec * pmdec) > 1e3 A naive way of implementing the query could be: Imagine we are interested in all stars in DR2 with proper motion larger than 1 arcsec/yr. The introductory tutorials White dwarfs exploration and Cluster analysis are recommended in case of difficulties following this exercise. This is an intermediate level tutorial that assumes a basic knowledge of the general interface and workflow. In this tutorial, some common hints and recipes are provided. INNER JOIN gaiadr1.rrlyrae AS rr USING (source_id)Ī recurrent subject in Helpdesk requests is support on queries timing out before completion.
Query: SELECT stat.num_observations_processed, rr.*įROM gaiadr1.phot_variable_time_series_gfov_statistical_parameters AS stat Target table: gaiadr1.rrlyrae, gaiadr1.phot_variable_time_series_gfov_statistical_parameters Use case: I want high-level information for a given class of variable objects (DR1, Gaia Collaboration, Clementini et al. RR Lyrae: number of data points and estimated parameters INNER JOIN gaiadr1.rrlyrae AS rrlyrae USING (source_id) Query: SELECT curves.observation_time, MOD(curves.observation_time - rrlyrae.epoch_g, rrlyrae.p1)/ rrlyrae.p1 AS phase,Ĭurves.g_magnitude, 2.5 / log(10) * curves.g_flux_error / curves.g_flux AS g_magnitude_errorįROM gaiadr1.phot_variable_time_series_gfov AS curves Target table: gaiadr1.rrlyrae, gaiadr1.phot_variable_time_series_gfov Notes: After Gaia DR1, light curves are being provided via the DataLink interface (see dedicated Tutorial). Use case: I want to construct a phase-folded light curve for comparison to stars with different periods (DR1, Gaia Collaboration, Brown et al. RR Lyrae: phase-folded light curve reconstruction, including errors INNER JOIN gaiadr1.cepheid AS cep USING (source_id) Target table: gaiadr1.cepheid, gaiadr1.phot_variable_time_series_gfovįROM gaiadr1.phot_variable_time_series_gfov AS gaia Notes: After DR1 light curves are provided via DataLink interface (see dedicated Tutorial).
Show interface errors gaia Offline#
Use case: I want to retrieve complete epoch photometry of a given object class for offline analysis (DR1, Gaia Collaboration, Clementini et al. LEFT OUTER JOIN gaiadr2.vari_long_period_variable AS soslpv USING (source_id)
LEFT OUTER JOIN gaiadr2.vari_rrlyrae AS sosrrl USING (source_id) LEFT OUTER JOIN gaiadr2.vari_classifier_result AS variables USING (source_id) Query: SELECT gaia.source_id, phot_variable_flag, best_class_name, datalink_url, sosrrl.pf, sosrrl.epoch_g, equency Target table: gaiadr2.gaia_source, gaiadr2.vari_rrlyrae, gaiadr2.vari_long_period_variable, gaiadr2.vari_classifier_result Use case: I want to retrieve the light curves for two variable stars (DR2, Gaia Collaboration, Holl et al. The output should be ordered by the angular separation from the centre, from small to large. Use case: I want to retrieve a sample of filtered sources in a circular region centred on the Large Magellanic Coud with a search radius of 5 arcmin ( EDR3, Gaia Collaboration, Luri et al. Cone search (radius 5') sorted by angular separation
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