Leave sample exclude_columns for later

lib/cartodb/backends/layer-stats/mapnik-layer-stats.js

@@ -149,29 +149,13 @@ function mergeColumns(results) {
 const SAMPLE_SEED = 0.5;
 const DEFAULT_SAMPLE_ROWS = 100;
 
-function exclude(items, excludedItems) {
-    if (excludedItems) {
-        return items.filter(item => !excludedItems.includes(item));
-    }
-    return items;
-}
-
-function _sample(ctx, numRows, availableColumns = null) {
+function _sample(ctx, numRows) {
     if (ctx.metaOptions.sample) {
         const sampleProb = Math.min(ctx.metaOptions.sample.num_rows / numRows, 1);
         // 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;
-        if (columns) {
-            columns = exclude(columns, ctx.metaOptions.sample.exclude_columns);
-        }
-        else if (ctx.metaOptions.sample.exclude_columns) {
-            if (availableColumns === null) {
-                return Promise.reject(new Error('Column stats are needed to use the sample exclude columns options'));
-            }
-            columns = exclude(availableColumns, ctx.metaOptions.sample.exclude_columns);
-        }
         return queryPromise(ctx.dbConnection, _getSQL(
             ctx,
             sql => queryUtils.getQuerySample(sql, sampleProb, limit, SAMPLE_SEED, columns)