diff options
Diffstat (limited to 'src/backend/access/transam/varsup.c')
| -rw-r--r-- | src/backend/access/transam/varsup.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c index e14b53bf9e3..0142bc70f6a 100644 --- a/src/backend/access/transam/varsup.c +++ b/src/backend/access/transam/varsup.c @@ -350,27 +350,30 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid, Oid oldest_datoid) /* * We'll refuse to continue assigning XIDs in interactive mode once we get - * within 1M transactions of data loss. This leaves lots of room for the + * within 3M transactions of data loss. This leaves lots of room for the * DBA to fool around fixing things in a standalone backend, while not * being significant compared to total XID space. (Note that since * vacuuming requires one transaction per table cleaned, we had better be - * sure there's lots of XIDs left...) + * sure there's lots of XIDs left...) Also, at default BLCKSZ, this + * leaves two completely-idle segments. In the event of edge-case bugs + * involving page or segment arithmetic, idle segments render the bugs + * unreachable outside of single-user mode. */ - xidStopLimit = xidWrapLimit - 1000000; + xidStopLimit = xidWrapLimit - 3000000; if (xidStopLimit < FirstNormalTransactionId) xidStopLimit -= FirstNormalTransactionId; /* - * We'll start complaining loudly when we get within 10M transactions of - * the stop point. This is kind of arbitrary, but if you let your gas - * gauge get down to 1% of full, would you be looking for the next gas - * station? We need to be fairly liberal about this number because there - * are lots of scenarios where most transactions are done by automatic - * clients that won't pay attention to warnings. (No, we're not gonna make - * this configurable. If you know enough to configure it, you know enough - * to not get in this kind of trouble in the first place.) + * We'll start complaining loudly when we get within 40M transactions of + * data loss. This is kind of arbitrary, but if you let your gas gauge + * get down to 2% of full, would you be looking for the next gas station? + * We need to be fairly liberal about this number because there are lots + * of scenarios where most transactions are done by automatic clients that + * won't pay attention to warnings. (No, we're not gonna make this + * configurable. If you know enough to configure it, you know enough to + * not get in this kind of trouble in the first place.) */ - xidWarnLimit = xidStopLimit - 10000000; + xidWarnLimit = xidWrapLimit - 40000000; if (xidWarnLimit < FirstNormalTransactionId) xidWarnLimit -= FirstNormalTransactionId; |