From: jon Date: August 18 2006 10:54am Subject: svn commit - mysqldoc@docsrva: r3051 - in trunk: refman-4.1 refman-5.0 refman-5.1 List-Archive: http://lists.mysql.com/commits/10615 Message-Id: <200608181054.k7IAsqDD025317@docsrva.mysql.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Author: jstephens Date: 2006-08-18 12:54:48 +0200 (Fri, 18 Aug 2006) New Revision: 3051 Log: Cluster FAQ: - Reworded PK/UK memory requirements (Thanks, Roland!) - Updated info about USING HASH and performance (Thanks, Pekka and Mikael!) Modified: trunk/refman-4.1/mysql-cluster.xml trunk/refman-5.0/mysql-cluster.xml trunk/refman-5.1/mysql-cluster.xml Modified: trunk/refman-4.1/mysql-cluster.xml =================================================================== --- trunk/refman-4.1/mysql-cluster.xml 2006-08-18 10:13:34 UTC (rev 3050) +++ trunk/refman-4.1/mysql-cluster.xml 2006-08-18 10:54:48 UTC (rev 3051) Changed blocks: 2, Lines Added: 31, Lines Deleted: 11; 3145 bytes @@ -14629,9 +14629,9 @@ means that all table data (including indexes) is stored in RAM. Therefore, if your data takes up 1GB of space and you want to replicate it once in the cluster, you need 2GB of - memory to do so. This is in addition to the memory required by - the operating system and any applications running on the - cluster computers. + memory to do so (1 GB per replica). This is in addition to the + memory required by the operating system and any applications + running on the cluster computers. @@ -14694,20 +14694,40 @@ Creating a primary key or unique index also creates an ordered index, unless this index is created with - USING HASH. In other words, if created - without USING HASH, a primary key or - unique index on a Cluster table takes up 31−35 bytes - per record in MySQL ¤t-series;. + USING HASH. In other words: - + + + + + A primary key or unique index on a Cluster table + normally takes up 31 to 35 bytes per record. + + + + + + However, if the primary key or unique index is created + with USING HASH, then it requires + only 21 to 25 bytes per record. + + + + Note that creating MySQL Cluster tables with USING HASH for all primary keys and unique indexes will generally cause table updates to run - more quickly. This is due to the fact that less memory is - required (because no ordered indexes are created), and + more quickly — in some cases by a much as 20 to 30 + percent faster than updates on tables where USING + HASH was not used in creating primary and + unique keys. This is due to the fact that less memory is + required (because no ordered indexes are created), and that less CPU must be utilized (because fewer indexes must - be read and possibly updated). + be read and possibly updated). However, it also means that + queries that could otherwise use range scans must be + satisfied by other means, which can result in slower + selects. Modified: trunk/refman-5.0/mysql-cluster.xml =================================================================== --- trunk/refman-5.0/mysql-cluster.xml 2006-08-18 10:13:34 UTC (rev 3050) +++ trunk/refman-5.0/mysql-cluster.xml 2006-08-18 10:54:48 UTC (rev 3051) Changed blocks: 2, Lines Added: 31, Lines Deleted: 11; 3145 bytes @@ -14976,9 +14976,9 @@ means that all table data (including indexes) is stored in RAM. Therefore, if your data takes up 1GB of space and you want to replicate it once in the cluster, you need 2GB of - memory to do so. This is in addition to the memory required by - the operating system and any applications running on the - cluster computers. + memory to do so (1 GB per replica). This is in addition to the + memory required by the operating system and any applications + running on the cluster computers. @@ -15041,20 +15041,40 @@ Creating a primary key or unique index also creates an ordered index, unless this index is created with - USING HASH. In other words, if created - without USING HASH, a primary key or - unique index on a Cluster table takes up 31−35 bytes - per record in MySQL ¤t-series;. + USING HASH. In other words: - + + + + + A primary key or unique index on a Cluster table + normally takes up 31 to 35 bytes per record. + + + + + + However, if the primary key or unique index is created + with USING HASH, then it requires + only 21 to 25 bytes per record. + + + + Note that creating MySQL Cluster tables with USING HASH for all primary keys and unique indexes will generally cause table updates to run - more quickly. This is due to the fact that less memory is - required (because no ordered indexes are created), and + more quickly — in some cases by a much as 20 to 30 + percent faster than updates on tables where USING + HASH was not used in creating primary and + unique keys. This is due to the fact that less memory is + required (because no ordered indexes are created), and that less CPU must be utilized (because fewer indexes must - be read and possibly updated). + be read and possibly updated). However, it also means that + queries that could otherwise use range scans must be + satisfied by other means, which can result in slower + selects. Modified: trunk/refman-5.1/mysql-cluster.xml =================================================================== --- trunk/refman-5.1/mysql-cluster.xml 2006-08-18 10:13:34 UTC (rev 3050) +++ trunk/refman-5.1/mysql-cluster.xml 2006-08-18 10:54:48 UTC (rev 3051) Changed blocks: 2, Lines Added: 32, Lines Deleted: 12; 3337 bytes @@ -17282,10 +17282,10 @@ Previous to MySQL 5.1, Cluster was in-memory only. This meant that all table data (including indexes) was stored in RAM. If your data took up 1GB of space and you wanted to replicate it - once in the cluster, you needed 2GB of memory to do so. This - was in addition to the memory required by the operating system - and any applications running on the cluster computers. This is - still true of in-memory tables. + once in the cluster, you needed 2GB of memory to do so (1 GB + per replica). This was in addition to the memory required by + the operating system and any applications running on the + cluster computers. This is still true of in-memory tables. @@ -17349,20 +17349,40 @@ Creating a primary key or unique index also creates an ordered index, unless this index is created with - USING HASH. In other words, if created - without USING HASH, a primary key or - unique index on a Cluster table takes up 31−35 bytes - per record in MySQL ¤t-series;. + USING HASH. In other words: - + + + + + A primary key or unique index on a Cluster table + normally takes up 31 to 35 bytes per record. + + + + + + However, if the primary key or unique index is created + with USING HASH, then it requires + only 21 to 25 bytes per record. + + + + Note that creating MySQL Cluster tables with USING HASH for all primary keys and unique indexes will generally cause table updates to run - more quickly. This is due to the fact that less memory is - required (because no ordered indexes are created), and + more quickly — in some cases by a much as 20 to 30 + percent faster than updates on tables where USING + HASH was not used in creating primary and + unique keys. This is due to the fact that less memory is + required (because no ordered indexes are created), and that less CPU must be utilized (because fewer indexes must - be read and possibly updated). + be read and possibly updated). However, it also means that + queries that could otherwise use range scans must be + satisfied by other means, which can result in slower + selects.