Reword comment for clarity

Reported by Masahiko Sawada
Discussion: https://postgr.es/m/CAD21AoB+ycZ2z-4Ye=6MfQ_r0aV5r6cvVPw4kOyPdp6bHqQoBQ@mail.gmail.com
This commit is contained in:
Alvaro Herrera 2017-08-12 21:36:07 -04:00
parent e88928c50d
commit 2336f84284
1 changed files with 3 additions and 3 deletions

View File

@ -1116,9 +1116,9 @@ SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xact
* so, because we only need to do it for catalog transactions since we
* only ever look at those.
*
* NB: Because of that xmax can be lower than xmin, because we only
* increase xmax when a catalog modifying transaction commits. While odd
* looking, it's correct and actually more efficient this way since we hit
* NB: We only increase xmax when a catalog modifying transaction commits
* (see SnapBuildCommitTxn). Because of this, xmax can be lower than xmin,
* which looks odd but is correct and actually more efficient, since we hit
* fast paths in tqual.c.
*/
builder->xmin = running->oldestRunningXid;