Hi, pCALC (partial checkpoint) is an extension to the CALC algorithm and yes, it is not implemented in openGauss. MOT only supports full checkpoint now. Regarding the overhead, there will be I/O overhead whenever checkpoint happens, but it won't block or affect normal user operations.
Regards, Vinoth ________________________________ From: qinhao@newland.com.cn qinhao@newland.com.cn Sent: Tuesday, June 21, 2022 3:22 PM To: community community@opengauss.org Subject: [Community] OpenGauss没有实现pCALC吗？（OpenGauss does not implement pCALC？）
Hi
最近在对比CALC的论文研究MOT检查点代码，发现capture阶段向磁盘写数据的代码，好像没有实现CALC论文中所讲的pCALC，每次做checkpoint，将MOT表所有记录都写到磁盘文件（CheckpointWorkerPool::WriteTableDataFile）中，而不是只保存修改了的记录，我找不到实现pCALC的代码，这样做checkpoint是不是代价太大了？而且我在代码中发现"MOT does not support incremental checkpoint"，这是不是说目前不支持CALC中的pCALC？如果我的理解有问题，请纠正。
Recently, I was studying the MOT checkpoint code comparing with CALC paper, and found no implemention of pCALC, which means, in the capture phase, all MOT records are written to the disk(CheckpointWorkerPool::WriteTableDataFile), not just updated records. Is it too expensive to save all records of MOT tables? And I found some messages in code like "MOT does not support incremental checkpoint", does that mean pCALC is not supported in OpenGauss currently？Please correct me, if my understanding is wrong.
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