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It is proposed to create an end-to-end streaming solution, from Repository (database) to Rest interfacePersistence layer to Controller. A Proof of Concept will be constructed to document challenges and investigate performance characteristics.
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// In CPS core
Stream<DataNode> queryDataNodesAsStream(String dataspaceName, String anchorName, String cpsPath, FetchDescendantsOption fetchDescendantsOption) {
return fragmentRepository.streamByAnchorAndCpsPath(getAnchor(dataspaceName, anchorName), cpsPath)
.map(fragment -> fetchDescendants(fragment, fetchDescendantsOption))
.map(fragment -> toDataNodeconvertToDataNode(fragment));
}
// In NCMP
private YangModelCmHandle getAnyReadyCmHandleByModuleSetTag(final String moduleSetTag) {
return cmHandleQueries.queryNcmpRegistryByCpsPath("/dmi-registry/cm-handles[@module-set-tag='" + moduleSetTag + "']", DIRECT_CHILDREN_ONLY)
.map(YangDataConverter::convertCmHandleToYangModel)
.filter(cmHandle -> cmHandle.getCompositeState().getCmHandleState() == CmHandleState.READY)
.findFirst()
.orElse(null);
}
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Instead of returning Collections from Rest APIs, a Stream may be returned, reducing memory pressure on the server.
Current code looks like this:Rest APIs return ResponseEntity using Lists. This means the whole structure must be held in memory before returning response.
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@Override
public ResponseEntity<List<String>> searchCmHandleIds(final CmHandleQueryParameters cmHandleQueryParameters) {
final CmHandleQueryServiceParameters cmHandleQueryServiceParameters = ncmpRestInputMapper.toCmHandleQueryServiceParameters(cmHandleQueryParameters);
final Collection<String> cmHandleIds = networkCmProxyDataService.executeCmHandleIdSearchForInventory(cmHandleQueryServiceParameters);
return ResponseEntity.ok(List.copyOf(cmHandleIds));
} |
It is proposed to stream out of the Rest API, something like this:return a Stream instead - Spring Boot supports this, and will allow returning very large results without incurring memory penalty.
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@Override
public Stream<String> searchCmHandleIds(final CmHandleQueryParameters cmHandleQueryParameters) {
final CmHandleQueryServiceParameters cmHandleQueryServiceParameters = ncmpRestInputMapper.toCmHandleQueryServiceParameters(cmHandleQueryParameters);
return networkCmProxyDataService.executeCmHandleIdSearchForInventory(cmHandleQueryServiceParameters);
} |
Details of current memory consumption - conversion of collections
The read APIs in CPS Core (cps-service and cps-ri) return Collection<DataNode>:
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