I was trying to understand the v1 patch and found that at the end
RequestCheckpoint() is called unconditionally, I think that should
have been called if REDO had performed, here is the snip from the v1
patch:
/*
- * If this was a promotion, request an (online) checkpoint now. This isn't
- * required for consistency, but the last restartpoint might be far back,
- * and in case of a crash, recovering from it might take a longer than is
- * appropriate now that we're not in standby mode anymore.
+ * Request an (online) checkpoint now. Note that, until this is complete,
+ * a crash would start replay from the same WAL location we did, or from
+ * the last restartpoint that completed. We don't want to let that
+ * situation persist for longer than necessary, since users don't like
+ * long recovery times. On the other hand, they also want to be able to
+ * start doing useful work again as quickly as possible. Therfore, we
+ * don't pass CHECKPOINT_IMMEDIATE to avoid bogging down the system.
+ *
+ * Note that the consequence of requesting a checkpoint here only after
+ * we've allowed WAL writes is that a single checkpoint cycle can span
+ * multiple server lifetimes. So for example if you want to something to
+ * happen at least once per checkpoint cycle or at most once per
+ * checkpoint cycle, you have to consider what happens if the server
+ * is restarted someplace in the middle.
*/
- if (promoted)
- RequestCheckpoint(CHECKPOINT_FORCE);
+ RequestCheckpoint(CHECKPOINT_FORCE);
When I try to call that conditionally like attached, I don't see any
regression failure, correct me if I am missing something here.
Regards,
Amul