DB2 9 & 10 for z/OS Overview

Migration Planning WorkshopCompress on INSERT• INSERT, MERGE and LOAD trigger the creation of a compressiondirectory if:– The table space or partition is defined with COMPRESS YES– The table space or partition has no compression dictionary built– Inserted data reaches a threshold that allows the build of thecompression dictionary• If threshold is reached, dictionary build is done asynchronously– Data continues to be inserted uncompressed until dictionary is ready– Rows read with UR in order to build the dictionary– DSNU235I – dictionary not built• Default behaviour Compress on insert– Use COMPRESS NO if unwanted117© 2011 IBM Corporation