Commit 58eff329 authored by paul@teton.kitebird.com's avatar paul@teton.kitebird.com
Browse files

manual.texi Clean up some MERGE uses. 

manual.texi	Change note mods, 4.0.2.
parent 42af46ca

Docs/manual.texi

+14 −12
Original line number Diff line number Diff line
@@ -845,7 +845,7 @@ files by using the @code{RAID} option. @xref{CREATE TABLE}. 














Another solution can be the included @code{MERGE} library, which allows















you to handle a collection of identical tables as one.













@xref{MERGE, MERGE tables}.













@xref{MERGE, , @code{MERGE} tables}.











































@node Year 2000 compliance,  , Table size, What-is










@@ -35283,7 +35283,8 @@ to the datafile, the @code{RAID} handler will map the first













@code{RAID_CHUNKSIZE} *1024 bytes to the next file and so on.















@item















@code{UNION} is used when you want to use a collection of identical













tables as one. This only works with MERGE tables. @xref{MERGE}.













tables as one. This only works with @code{MERGE} tables.













@xref{MERGE, , @code{MERGE}}.





























For the moment you need to have @strong{select}, @strong{update}, and















@strong{delete} privileges on the tables you map to a @code{MERGE} table.










@@ -37266,9 +37267,9 @@ will only clear the mapping for the table, not delete everything in the













mapped tables. (We plan to fix this in 4.1).





























With identical tables we mean that all tables are created with identical













column and key information.  You can't put a MERGE over tables where the













columns are packed differently, doesn't have exactly the same columns or













have the keys in different order.  Some of the tables can however be













column and key information.  You can't merge tables in which the













columns are packed differently, doesn't have exactly the same columns,













or have the keys in different order.  However, some of the tables can be















compressed with @code{myisampack}.  @xref{myisampack, , @code{myisampack}}.





























When you create a @code{MERGE} table, you will get a @file{.frm} table










@@ -37296,7 +37297,7 @@ kind of benefits.)













@item















Do more efficient searches. If you know exactly what you are looking















after, you can search in just one of the split tables for some queries













and use @strong{MERGE} table for others.  You can even have many













and use @code{MERGE} table for others.  You can even have many















different @code{MERGE} tables active, with possible overlapping files.















@item















More efficient repairs. It's easier to repair the individual files that









@@ -37314,9 +37315,10 @@ This is much faster and will save a lot of disk space.













@item















Go around the file-size limit for the operating system.















@item













You can create an alias/synonym for a table by just using MERGE over one













table. There shouldn't be any really notable performance impacts of doing this













(only a couple of indirect calls and memcpy's for each read).













You can create an alias/synonym for a table by just using @code{MERGE}













over one table. There shouldn't be any really notable performance













impacts of doing this (only a couple of indirect calls and @code{memcpy()}













calls for each read).















@end itemize





























The disadvantages with @code{MERGE} tables are:









@@ -37330,7 +37332,7 @@ You can only use identical @code{MyISAM} tables for a @code{MERGE} table.













@code{REPLACE} doesn't work.















@item















@code{MERGE} tables uses more file descriptors. If you are using a













@strong{MERGE} that maps over 10 tables and 10 users are using this, you













@code{MERGE} that maps over 10 tables and 10 users are using this, you















are using 10*10 + 10 file descriptors.  (10 datafiles for 10 users















and 10 shared index files.)















@item










@@ -49118,10 +49120,10 @@ Fixed bug in phrase operator @code{"..."} in boolean fulltext search.













Fixed bug that caused duplicated rows when using truncation operator















@code{*} in boolean fulltext search.















@item













Fixed bug in boolean fulltext search, that caused a crash when an identical













Fixed bug in boolean fulltext search that caused a crash when an identical















@code{MATCH} expression that did not use an index appeared twice.















@item













Query cache disabled in mysqldump.













Query cache disabled in @code{mysqldump}.















@item















Fixed problem on Windows 98 that made sending of results very slow.















@item