Df 0 2 7_ S Qlite Dependency Over Version

Plot the ROOT downloads based on the version reading a remote sqlite3 file.

This tutorial uses the Reduce method which allows to extract the minimum time stored in the SQlite3 database. The next step is to create a TH1F Histogram, which will be filled with the values stored in two different columns from the database. This procedure is simplified with a lambda expression that takes as parameters the values stored in the "Time" and "Version" columns.

Author: Alexandra-Maria Dobrescu
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, June 15, 2021 at 07:21 AM.

In [1]:
auto rdfb = ROOT::RDF::MakeSqliteDataFrame("http://root.cern/files/root_download_stats.sqlite", "SELECT * FROM accesslog;" );

auto minTimeStr = *rdfb.Reduce([](std::string a, std::string b) {return std::min(a, b);}, "Time", std::string("Z"));

std::cout << "Minimum time is '" << minTimeStr << "'" << std::endl;

double minTime = TDatime(minTimeStr.c_str()).Convert();
double now = TDatime().Convert();

auto rdf = rdfb.Define("datime", [](const std::string &time){return TDatime(time.c_str()).Convert();}, {"Time"});

auto h614 = rdf.Filter([](const std::string &v){ return 0 == v.find("6.14");}, {"Version"})
               .Histo1D({"h614", "Download time for version 6.14", 16, minTime, now}, {"datime"});

auto h616 = rdf.Filter([](const std::string &v){ return 0 == v.find("6.16");}, {"Version"})
               .Histo1D({"h616", "Download time for version 6.16", 16, minTime, now}, {"datime"});

auto h618 = rdf.Filter([](const std::string &v){ return 0 == v.find("6.18");}, {"Version"})
               .Histo1D({"h618", "Download time for version 6.18", 16, minTime, now}, {"datime"});
Minimum time is '2018-07-06 07:54:32'

Add here a newer version!

In [2]:
auto histoList = {h614, h616, h618};
auto canvases = new std::vector<TCanvas*>(histoList.size());

auto histoIdx = 0U;
for (auto histo : histoList) {
   canvases->at(histoIdx) = new TCanvas();
   histo->GetXaxis()->SetNdivisions(512, kFALSE);
Warning in <TAxis::Sort>: Cannot sort. No labels
Warning in <TAxis::Sort>: Cannot sort. No labels
Warning in <TAxis::Sort>: Cannot sort. No labels

Draw all canvases

In [3]:
%jsroot on