diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/transam/multixact.c | 24 | ||||
| -rw-r--r-- | src/backend/access/transam/varsup.c | 27 |
2 files changed, 25 insertions, 26 deletions
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index ce84dac0c40..475f5ed8611 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -2217,28 +2217,24 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid oldest_datoid, multiWrapLimit += FirstMultiXactId; /* - * We'll refuse to continue assigning MultiXactIds once we get within 100 - * multi of data loss. - * - * Note: This differs from the magic number used in - * SetTransactionIdLimit() since vacuum itself will never generate new - * multis. XXX actually it does, if it needs to freeze old multis. + * We'll refuse to continue assigning MultiXactIds once we get within 3M + * multi of data loss. See SetTransactionIdLimit. */ - multiStopLimit = multiWrapLimit - 100; + multiStopLimit = multiWrapLimit - 3000000; if (multiStopLimit < FirstMultiXactId) multiStopLimit -= FirstMultiXactId; /* - * We'll start complaining loudly when we get within 10M multis 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 + * We'll start complaining loudly when we get within 40M multis 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.) */ - multiWarnLimit = multiStopLimit - 10000000; + multiWarnLimit = multiWrapLimit - 40000000; if (multiWarnLimit < FirstMultiXactId) multiWarnLimit -= FirstMultiXactId; 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; |