资 源 简 介
This project provides support for variable size records (aka dynamic row format) in MySQL Heap (Memory) Engine.
Contributed under GPL2 by eBay, Inc April 2008
As of March 2008, MySQL Heap Engine of any version is limited to fixed row format. It allocates fixed memory size for each record stored in a given Heap Table. For example, if table A has a VARCHAR(4000) column, MySQL will use at least 4000 bytes (plus other columns and per-record overhead) for every record regardless of whether it has that much user data. In this example, the table will use 4GB memory per 1M records.
Assuming that actual data in a VARCHAR varies (average data length is less than maximum), it would be best if Heap Engine could optimize its memory use. In the example above, if average VARCHAR data was 1000 bytes, the memory consumption would be 1GB rather than 4GB.
This project changes memory allocation mechanisms used by the MySQL Heap Engine. Each Heap Table uses separ
文 件 列 表
heap
CMakeLists.txt
heapdef.h
hp_block.c
hp_clear.c
hp_create.c
hp_delete.c
hp_dspace.c
hp_hash.c
hp_info.c
hp_open.c
hp_record.c
hp_rfirst.c
hp_rkey.c
hp_rlast.c
hp_rnext.c
hp_rprev.c
hp_rrnd.c
hp_rsame.c
hp_scan.c
hp_test1.c
hp_test2.c
hp_update.c
hp_write.c
Makefile.am
Makefile.in
_check.c
_rectest.c
include
heap.h
sql
handler.h
ha_heap.cc
ha_heap.h
lex.h
sql_show.cc
sql_table.cc
sql_yacc.yy
table.cc
table.h
mysql-test
r
t
diff_2008_07_30.txt
