CartoDB-SQL-API/app/services/query-tables-api.js

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var PSQL = require('cartodb-psql');
var generateMD5 = require('../utils/md5');
var queryMayWrite = require('../utils/query_may_write');
function QueryTablesApi(tableCache) {
this.tableCache = tableCache;
}
module.exports = QueryTablesApi;
QueryTablesApi.prototype.getAffectedTablesAndLastUpdatedTime = function (connectionParams, sql, callback) {
var self = this;
var sqlCacheKey = generateMD5(sql);
var queryExplainResult = this.tableCache.get(sqlCacheKey);
if (queryExplainResult) {
queryExplainResult.hits++;
return callback(null, queryExplainResult);
}
var query = [
'WITH querytables AS (',
'SELECT * FROM CDB_QueryTablesText($quotesql$' + sql + '$quotesql$) as tablenames',
')',
'SELECT (SELECT tablenames FROM querytables), EXTRACT(EPOCH FROM max(updated_at)) as max',
'FROM CDB_TableMetadata m',
'WHERE m.tabname = any ((SELECT tablenames from querytables)::regclass[])'
].join(' ');
var pg = new PSQL(connectionParams, {}, { destroyOnError: true });
pg.query(query, function handleAffectedTablesAndLastUpdatedTimeRows(err, resultSet) {
resultSet = resultSet || {};
var rows = resultSet.rows || [];
if (err || rows.length !== 1) {
var errorMessage = (err && err.message) || 'unknown error';
console.error("Error on query explain '%s': %s", sql, errorMessage);
}
var result = rows[0] || {};
// This is an Array, so no need to split into parts
var tableNames = result.tablenames || [];
var lastUpdatedTime = (Number.isFinite(result.max)) ? (result.max * 1000) : Date.now();
var queryExplainResult = {
affectedTables: tableNames,
lastModified: lastUpdatedTime,
mayWrite: queryMayWrite(sql),
hits: 1
};
self.tableCache.set(sqlCacheKey, queryExplainResult);
return callback(null, queryExplainResult);
}, true);
};