Expert Oracle Exadata - Parent Directory

CHAPTER 4 STORAGE INDEXESStorage Indexes will still be updated when values in a table are changed, even if this parameter is set toTRUE._kcfis_storageidx_diag_modeThe second parameter, __KCFIS_STORAGEIDX_DIAG_MODE, looks eerily like the cellinit.ora parameter_CELL_STORAGE_INDEX_DIAG_MODE, which was discussed earlier. As you might expect, setting thisparameter at the database layer causes trace files to be generated across all the affected storage cells.Setting it to a value of 2 enables tracing. Oddly, setting it to a value of 1 disables Storage Indexes.Unfortunately, the trace files are created on the storage cells. But this method of generating them ismuch less intrusive than restarting the cellsrv process on a storage server.You can set the parameter at the session level with the alter session statement:alter session set "_kcfis_storageidx_diag_mode"=2;There may be other valid values for the parameter that enable different levels of tracing. Keep inmind that this will produce a large number of trace files on every storage cell that is involved in a querythat uses Storage Indexes._cell_storidx_modeThe _CELL_STORIDX_MODE parameter was added in the second point release of Oracle Database 11gR2(11.2.0.2). While this parameter is undocumented, it appears that it controls where Storage Indexes willbe applied. There are three valid values for this parameter (EVA,KDST,ALL). EVA and KDST are Oracle kernelfunction names.You can set the parameter at the session level with the alter session statement:alter session set "_cell_storidx_mode"=ALL;The effects of this parameter have varied across releases. As of cellsrv version 11.2.2.3.0, EVA (thedefault) supports all the valid comparison operators. You should note that in older versions, the EVAsetting did not support the IS NULL comparison operator. It’s also important to keep in mind that thedatabase patching is tied to the storage software patching. Upgrading the version of cellsrv withoutpatching the database software can result in unpredicatable behavior (disabling storage indexes forexample).Storage Software ParametersIn addition to the database parameters, there are also a number of undocumented storage softwareparameters that are related to Storage Index behavior. These parameters can be modified by addingthem to the cellinit.ora file and then restarting cellsrv. Note that cellinit.ora will be discussed in moredetail in Chapter 8. Here is a list of the cellinit.ora Storage Index parameters along with their defaultvalues.• _cell_enable_storage_index_for_loads=TRUE• _cell_enable_storage_index_for_writes=TRUE• _cell_si_max_num_diag_mode_dumps=20• _cell_storage_index_columns=0• _cell_storage_index_diag_mode=FALSE112