maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Aleksey!

On Dec 23, Aleksey Midenkov wrote:
> revision-id: 7198e7c71fc (versioning-1.0.6-82-g7198e7c71fc)
> parent(s): 6be155757b7
> author: Aleksey Midenkov <midenok@xxxxxxxxx>
> committer: Aleksey Midenkov <midenok@xxxxxxxxx>
> timestamp: 2018-12-20 13:25:00 +0300
> message:
> 
> MDEV-15458 Segfault in heap_scan() upon UPDATE after ADD SYSTEM VERSIONING
> 
> * HA_EXTRA_REMEMBER_POS, HA_EXTRA_RESTORE_POS for HEAP storage engine
> * Versioning tests support

As far as I can see, there are two approaches to fixing this bug.
And if we go the way of HA_EXTRA_REMEMBER_POS/HA_EXTRA_RESTORE_POS then
your fix is good.

But I'd still like to understand whether write_row is supposed to
disturb the scan. Why should heap_write() overwrite
info->current_ptr=pos and info->current_hash_ptr? Inserting a row
doesn't happen at the "current position", so I don't quite understand
why it modifies current_ptr at all. There is no functionality like
"continue the scan from the last inserted row", right? It just doesn't
make sense to me.

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx