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1 | | -<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.73 2010/06/11 10:13:08 heikki Exp $ --> |
| 1 | +<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.74 2010/06/22 02:57:50 rhaas Exp $ --> |
2 | 2 |
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3 | 3 | <chapter id="high-availability"> |
4 | 4 | <title>High Availability, Load Balancing, and Replication</title> |
@@ -1330,7 +1330,7 @@ if (!triggered) |
1330 | 1330 | </listitem> |
1331 | 1331 | <listitem> |
1332 | 1332 | <para> |
1333 | | - LISTEN, UNLISTEN, NOTIFY |
| 1333 | + <command>LISTEN</>, <command>UNLISTEN</>, <command>NOTIFY</> |
1334 | 1334 | </para> |
1335 | 1335 | </listitem> |
1336 | 1336 | </itemizedlist> |
@@ -1437,14 +1437,14 @@ if (!triggered) |
1437 | 1437 | Some WAL redo actions will be for <acronym>DDL</> execution. These DDL |
1438 | 1438 | actions are replaying changes that have already committed on the primary |
1439 | 1439 | node, so they must not fail on the standby node. These DDL locks take |
1440 | | - priority and will automatically *cancel* any read-only transactions that |
1441 | | - get in their way, after a grace period. This is similar to the possibility |
1442 | | - of being canceled by the deadlock detector. But in this case, the standby |
1443 | | - recovery process always wins, since the replayed actions must not fail. |
1444 | | - This also ensures that replication does not fall behind while waiting for a |
1445 | | - query to complete. This prioritization presumes that the standby exists |
1446 | | - primarily for high availability, and that adjusting the grace period |
1447 | | - will allow a sufficient guard against unexpected cancellation. |
| 1440 | + priority and will automatically <emphasis>cancel</> any read-only |
| 1441 | + transactions that get in their way, after a grace period. This is similar |
| 1442 | + to the possibility of being canceled by the deadlock detector. But in this |
| 1443 | + case, the standby recovery process always wins, since the replayed actions |
| 1444 | + must not fail. This also ensures that replication does not fall behind |
| 1445 | + while waiting for a query to complete. This prioritization presumes that |
| 1446 | + the standby exists primarily for high availability, and that adjusting the |
| 1447 | + grace period will allow a sufficient guard against unexpected cancellation. |
1448 | 1448 | </para> |
1449 | 1449 |
|
1450 | 1450 | <para> |
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