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| -rw-r--r-- | doc/src/sgml/high-availability.sgml | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index d3ef45944f7..ccdfd8d1cb5 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.5 2006/11/21 18:15:45 momjian Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.6 2006/11/21 18:31:57 momjian Exp $ --> <chapter id="high-availability"> <title>High Availability and Load Balancing</title> @@ -166,16 +166,16 @@ protocol to make nodes agree on a serializable transactional order. </para> <para> - One limitation of this solution is that functions like + If queries are simply broadcast unmodified, functions like <function>random()</>, <function>CURRENT_TIMESTAMP</>, and - sequences can have different values on different servers. This - is because each server operates independently, and because SQL - queries are broadcast (and not actual modified rows). If this - is unacceptable, applications must query such values from a - single server and then use those values in write queries. - Also, care must be taken that all transactions either commit - or abort on all servers, perhaps using two-phase commit (<xref - linkend="sql-prepare-transaction" + sequences would have different values on different servers. + This is because each server operates independently, and because + SQL queries are broadcast (and not actual modified rows). If + this is unacceptable, either the middleware or the application + must query such values from a single server and then use those + values in write queries. Also, care must be taken that all + transactions either commit or abort on all servers, perhaps + using two-phase commit (<xref linkend="sql-prepare-transaction" endterm="sql-prepare-transaction-title"> and <xref linkend="sql-commit-prepared" endterm="sql-commit-prepared-title">. Pgpool is an example of this type of replication. |