Older logs are not loaded

# Expected behavior

I add a panel to the dashboard. Time range is set to whatever value I want, for example 1 hour.
Logs are displayed in the panel, newest on top. When I scroll to the bottom of the panel older logs are loaded. I can scroll and logs are loaded until I reach the end of the time frame I chose.

# Actual behavior

When I reach the bottom of the panel some older log entries are returned but how many seems to depend on the value of "max data points" in the panel configuration. If I have a lot of logs I can reach the bottom of the panel and the oldest ones are cut off. For example in a 1 hour window I can only see last 10 minutes of logs. Older entries are only loaded once.

Situtation is different in explore it seems. When I reach the bottom of the logs it says "Loading older logs" and loads them.

# Steps to reproduce

Create a logging panel that in a given time frame would show more logs than the value of "max data points" field. Some lines will not be shown.

I'm not sure if this behavior is the fault of the data source or the grafana logging panel.

まず、ログが設定された最大データポイント数を超える Grafana のロギングパネルで issue #91 を再現し、その後、Explore と動作を比較します。プラグインのログ読み込みのエントリポイントを追跡し、最初の古いバッチの後でページネーションが停止するかどうかを確認します。下までスクロールしたときに、選択した時間範囲内のすべてのログが読み込まれれば完了です。

索引モデルが issue の本文から書いたものです。