API query parameter restrictions
To ensure the stability and performance of the Data Explorer services and APIs, restrictions have been introduced on the use of certain query parameters for a limited number of very large datasets.
We have observed that some types of API queries can generate very heavy requests when applied to datasets containing large volumes of observations. In certain situations, this can impact overall system performance and affect the availability of the service for other users.
To mitigate this risk, server-level safeguards have been implemented to restrict the use of specific parameters for selected dataflows. The section below describes the parameters currently affected and the datasets concerned.
lastNObservations and firstNObservations
API requests using lastNObservations or firstNObservations are blocked for the entire TiVA (sti-public) and the CRS (dcd-public) dedicated dissemination spaces. For the main data dissemination space (public) these parameter are blocked only for the large datasets listed below.
| Agency ID | Dataset |
|---|---|
| OECD.SDD.TPS | DSD_BATIS@DF_BATIS |
| OECD.ENV.EPI | DSD_ECH@EXT_TEMP_P |
| OECD.STI.PIE | DSD_TIM_2023@DF_TIM_2023 |
| OECD.SDD.STES | DSD_STES_REVISIONS@DF_STES_REVISIONS |
| OECD.STI.PIE | DSD_TIM_2021@DF_TIM_2021 |
| OECD.SDD.TPS | DSD_BIMTS@DF_BIMTS_HS2017_2D |
| OECD.SDD.TPS | DSD_BIMTS@DF_BIMTS_CPA_2_1 |
| OECD.CFE.EDS | DSD_LA_EXTREME_TEMP_DDOWN@DF_EXTREME_TEMP_DDOWN |
| OECD.STI.PIE | DSD_TIMBC_2023@DF_TIMBC_2023 |
| OECD.EDU.IMEP | DSD_EAG_UOE_FIN@DF_UOE_FIN_INDIC_SOURCE_NATURE |
| OECD.CFE.EDS | DSD_LA_DEMO_POP_AGE_DDOWN@DF_POP_AGE_DDOWN |
| OECD.SDD.TPS | DSD_SDBSBSC_ISIC4@DF_SDBS_ISIC4 |
These datasets currently contain more than 20 million observations, and the use of these parameters, allowing data sorting, can generate very heavy queries that impact overall system performance.
Requests containing these parameters will return the following response:
413 – Request Entity Too Large
(The page was not displayed because the request entity is too large.)
This restriction only applies to direct API calls. Interactive usage through the OECD Data Explorer web browser page will continue to work normally, including the Time series values filter available in the time period selection.