indexedDb objectStore.openCursor so slow

Question

The first time using the index query takes too long.

usage scenarios: mobile use webview.

After the data is saved into indexedDb, the first time you open the page query is extremely slow.

query code:

var startTime = new Date().getTime();
var request = indexedDB.open("yfg");
request.onerror = function(event) {
	alert("Why didn't you allow my web app to use IndexedDB?!");
};
request.onsuccess = function(event) {
	var table = [];
	var db = request.result;
	var objectStore = db.transaction("table").objectStore("table");

	//objectStore.openCursor().onsuccess = function(event) {
	objectStore.openCursor(null,IDBCursor.NEXT).onsuccess = function(event) {
		var cursor = event.target.result;
		if (cursor) {
			table.push(cursor.value);
			cursor.continue();
		}else {
			//alert("No more entries!");
			console.log(table);
			var endTime = new Date().getTime();
			console.log("总耗时：",(endTime-startTime)/1000);
		}
	};
};

Execute on console:

The first result:

The second result:

Browser version:

The specific content of each piece of data:

This table sheet has these data:

bars? is that a new unit of measuring data? how many bytes in a bar? nevermind, just re-read the question properly and realise you're using IndexedDB — Jaromanda X

Josh Josh · Accepted Answer · 2017-11-27T22:18:33

Try using IDBObjectStore.prototype.getAll. getAll generates an array, similar to what you are doing, but involves fewer function calls than openCursor and is therefore more performant.

However, unlike openCursor, getAll may not be supported because it is a newer feature of indexedDB. The linked page shows a compatibility table but that may also be out of date.

indexedDb objectStore.openCursor so slow

1 Answers