diff --git a/lib/cartodb/backends/layer-stats/mapnik-layer-stats.js b/lib/cartodb/backends/layer-stats/mapnik-layer-stats.js
index 689edb9b..0390536b 100644
--- a/lib/cartodb/backends/layer-stats/mapnik-layer-stats.js
+++ b/lib/cartodb/backends/layer-stats/mapnik-layer-stats.js
@@ -172,13 +172,14 @@ function mergeColumns(results) {
     }
 }
 
-
 function _sample(ctx, numRows) {
     if (ctx.metaOptions.sample) {
         const sampleProb = Math.min(ctx.metaOptions.sample / numRows, 1);
+        // We'll use a safety limit just in case numRows is a bad estimate
+        const limit = Math.ceil(ctx.metaOptions.sample * 1.5);
         return queryPromise(
             ctx.dbConnection,
-            _getSQL(ctx, sql => queryUtils.getQuerySample(sql, sampleProb)),
+            _getSQL(ctx, sql => queryUtils.getQuerySample(sql, sampleProb, limit)),
             res => ({ sample: res.rows })
         );
     }
diff --git a/lib/cartodb/utils/query-utils.js b/lib/cartodb/utils/query-utils.js
index 0bbd38c0..a1276f5e 100644
--- a/lib/cartodb/utils/query-utils.js
+++ b/lib/cartodb/utils/query-utils.js
@@ -88,11 +88,12 @@ module.exports.getQueryTopCategories = function(query, column, topN, includeNull
     `;
 };
 
-module.exports.getQuerySample = function(query, sampleProb, randomSeed = 0.5) {
+module.exports.getQuerySample = function(query, sampleProb, limit = null, randomSeed = 0.5) {
     const singleTable = simpleQueryTable(query);
     if (singleTable) {
         return getTableSample(singleTable.table, singleTable.columns, sampleProb, randomSeed);
     }
+    const limitClause = limit ? `LIMIT ${limit}` : '';
     return `
         WITH __cdb_rndseed AS (
             SELECT setseed(${randomSeed})
@@ -100,14 +101,16 @@ module.exports.getQuerySample = function(query, sampleProb, randomSeed = 0.5) {
         SELECT *
             FROM (${query}) AS __cdb_query
             WHERE random() < ${sampleProb}
+            ${limitClause}
     `;
 };
 
-function getTableSample(table, columns, sampleProb, randomSeed) {
+function getTableSample(table, columns, sampleProb, limit = null, randomSeed = 0.5) {
+    const limitClause = limit ? `LIMIT ${limit}` : '';
     sampleProb *= 100;
     randomSeed *= Math.pow(2, 31) -1;
     return `
-        SELECT ${columns} FROM ${table} TABLESAMPLE BERNOULLI (${sampleProb}) REPEATABLE (${randomSeed})
+        SELECT ${columns} FROM ${table} TABLESAMPLE BERNOULLI (${sampleProb}) REPEATABLE (${randomSeed}) ${limitClause}
     `;
 }