The additional information displayed will be block number for error occurring while processing heap and index name for error occurring while processing the index.
This will help us in diagnosing the problems that occur during a vacuum. For ex. due to corruption (either caused by bad hardware or by some bug) if we get some error while vacuuming, it can help us identify the block in heap and or additional index information.
It sets up an error context callback to display additional information with the error. During different phases of vacuum (heap scan, heap
vacuum, index vacuum, index clean up, heap truncate), we update the error context callback to display appropriate information. We can extend it to a bit more granular level like adding the phases for FSM operations or for prefetching the blocks while truncating. However, I felt that it requires adding many more error callback function calls and can make the code a bit complex, so left those for now.
Author: Justin Pryzby, with few changes by Amit Kapila
b61d161c14 Introduce vacuum errcontext to display additional information.
src/backend/access/heap/vacuumlazy.c | 240 +++++++++++++++++++++++++++++++----
src/tools/pgindent/typedefs.list | 1 +
2 files changed, 216 insertions(+), 25 deletions(-)