Data Guard

How to Resolve Standby ORA-00600 [3020]

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ORA-00600 [3020] Found MRP shutdown with ORA-00600 [3020] in alert log of a standby database due to inconsistency of a newly created data file. Wed Nov 21 18:32:12 2018 Errors in file /oracle/admin/ORCL/bdump/orcl_mrp0_4589393.trc: ORA-00600: internal error code, arguments: [3020], [1786773511], [1], [37836], [320123], [72], [], [] ORA-10567: Redo is inconsistent with data block (file# 854, […]
UNDO

How to Resolve ORA-01555 UNDO_RETENTION

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ORA-01555 UNDO_RETENTION Let’s see the error ORA-01555 UNDO_RETENTION first: Description ORA-01555: snapshot too old: rollback segment number string with name “string” too small Cause rollback records needed by a reader for consistent read are overwritten by other writers Action If in Automatic Undo Management mode, increase undo_retention setting. Otherwise, use larger rollback segments Before we […]
Initialization Parameter

UNDO_RETENTION, How and Why

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UNDO_RETENTION At times, you may find out or feel that UNDO_RETENTION is useless at all. Raising the number of seconds cannot resolve ORA-01555. This is true under some specific conditions. Here I quote the requisites from the official document below: Fix-sized Undo Tablespace The UNDO_RETENTION parameter is ignored for a fixed size undo tablespace. The […]
UNDO

How to Check UNDO Tablespace Usage

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The first purpose of using UNDO is for storing all uncommitted data in case we need to undo uncommitted data in rollback or after system failures. As you know, UNDO could be growing very fast during system busy hours. If you ignore undo tablespace usage, some transactions may fail. In this post, we will discuss […]
Tablespace

How to Check Oracle Tablespace Usage

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After having the whole picture about the size of the database, we can further check Oracle tablespace usage solely by SQL. Oracle Tablespace Usage Of course, you can use GUI tools to check the space usage of tablespace in Oracle, but if someday, the only tool you got is sqlplus, a text-based tool, everything must […]