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Modify sample metadata

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This commit is contained in:
Daniel García Aubert 2019-08-23 17:09:24 +02:00
parent 71dba04d83
commit 25e3395580
1 changed files with 19 additions and 13 deletions
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32
lib/cartodb/backends/layer-stats/mapnik-layer-stats.js
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@ -125,22 +125,28 @@ function mergeColumns(results) {
} }
} }
const SAMPLE_SEED = 0.5;
const DEFAULT_SAMPLE_ROWS = 100; const DEFAULT_SAMPLE_ROWS = 100;
function _sample(ctx, numRows) { function _sample(ctx) {
if (ctx.metaOptions.sample) { if (!ctx.metaOptions.sample) {
const sampleProb = Math.min(ctx.metaOptions.sample.num_rows / numRows, 1); return Promise.resolve();
// We'll use a safety limit just in case numRows is a bad estimate
const requestedRows = ctx.metaOptions.sample.num_rows || DEFAULT_SAMPLE_ROWS;
const limit = Math.ceil(requestedRows * 1.5);
let columns = ctx.metaOptions.sample.include_columns;
return queryUtils.queryPromise(ctx.dbConnection, _getSQL(
ctx,
sql => queryUtils.getQuerySample(sql, sampleProb, limit, SAMPLE_SEED, columns)
)).then(res => ({ sample: res.rows }));
} }
return Promise.resolve();
// We'll use a safety limit just in case numRows is a bad estimate
const requestedRows = ctx.metaOptions.sample.num_rows || DEFAULT_SAMPLE_ROWS;
const limit = Math.ceil(requestedRows * 1.5);
const columns = ctx.metaOptions.sample.include_columns;
const sqlMaxMin = _getSQL(ctx, sql => queryUtils.getMaxMinColumnQuery(sql));
return queryUtils.queryPromise(ctx.dbConnection, sqlMaxMin)
.then(maxMinRes => {
const { min_id: min, id_span: span } = maxMinRes.rows[0];
const ids = queryUtils.getSampleValuesFromRange(min, span, limit);
const sqlSample = _getSQL(ctx, sql => queryUtils.getSampleFromIdsQuery(sql, ids, columns));
return queryUtils.queryPromise(ctx.dbConnection, sqlSample);
})
.then(res => ({ sample: res.rows }));
} }
function _columnsMetadataRequired(options) { function _columnsMetadataRequired(options) {