Month: January 2021

How big will be the new index?

In my last post about temporary tablespace, I talked about monitoring the usage during an index creation since it is one of activties which need sort segments. One question likely arises is how to estimate the size of an index so that we can add enough temp data files and data files ahead? If you … Continue reading How big will be the new index? →

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Monitor Temporary Tablespace Usage

Oracle database uses temporary tablespaces to improve the concurrency of multiple sort operations that do not fit in memory and can improve the efficiency of space management operations during sorts. Data created within this tablespace is transient and lasts only for the duration of the session/statment. It can store the following data: Intermediate sort resultsTemporary … Continue reading Monitor Temporary Tablespace Usage →

Converting column data type from clob to varchar?

From time to time, you might run into some tasks like converting column data type. Oracle has provided the feature with "alter table" statement with some limitations -- for example, you cannot change a column type from clob to varchar2 with it: SQL> desc jli_0104 Name Null? Type ------------------ -------- ------------ IUID CLOB SQL> ALTER … Continue reading Converting column data type from clob to varchar? →

ORA-01244: unnamed datafile(s) added to control file by media recovery

Using Point in Time Recovery to migrate a database from one server to another is a common method: you take an RMAN backup from the old server while it's running and restore it on the new server, then you keep copying archive logs from the old system to the new system and recover the database … Continue reading ORA-01244: unnamed datafile(s) added to control file by media recovery →

ORA-01623: log xx is current log for instance xxxx (thread 1) – cannot drop

When using RMAN to duplicate/TSPITR a database on a different server with a different disk layout, the parameters db_file_name_convert and log_file_name_convert can be used. However, when using RMAN restore, they cannot be used. Instead, "set newname for datafile" & "switch datafile" are needed for each data file to be restored with a new path and … Continue reading ORA-01623: log xx is current log for instance xxxx (thread 1) – cannot drop →

ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM]

We have had a few database upgraded from 12c/18c to 19c (running on Oracle Linux 7) recently and all of them have had this error during the startup of the database since the upgrade: ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM], [Check traces and OS configuration], [Check Oracle document and MOS notes], [] … Continue reading ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM] →