Author: Bambino
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Oracle SQL Tuning with AWR and ASH, Part 3: SQL Tuning Advisor, sqltrpt.sql, and Plan Stabilization
Use the evidence from AWR and ASH to evaluate tuning recommendations and stabilize a proven execution plan.
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Oracle SQL Tuning with AWR and ASH, Part 2: Diagnose with ASH and Runtime Plans
Use ASH to classify database activity and runtime execution plans to find where the time went during a slow SQL execution.
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Oracle SQL Tuning with AWR and ASH, Part 1: Find and Prove the Regression
Define the incident and use AWR evidence to identify the SQL, compare execution plans, and prove whether performance regressed.
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Fast Guide: PL/SQL
PL/SQL is Oracle’s procedural extension to SQL. It lets you combine SQL statements with variables, conditions, loops, reusable subprograms, and exception handling. This quick guide covers the pieces you will use most often. 1. The basic PL/SQL block A block has an optional declaration section, a required executable section, and an optional exception section. The…
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IMP-00017: Statement Failed with ORA-02304 During Schema Import
An Oracle schema import can fail when object types are imported back into the same database under a different schema. The log commonly shows IMP-00017 together with ORA-02304: invalid object identifier literal, or the Data Pump wrapper error ORA-39083. Why it happens Oracle object types can have database-wide object identifiers (OIDs). By default, an export…
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ORA-19511 / NetBackup Status 25: Cannot Connect on Socket
ORA-19511 is Oracle RMAN reporting an error returned by the media-management layer. When the accompanying NetBackup message is status 25: cannot connect on socket, troubleshoot the NetBackup connection rather than the Oracle database first. What status 25 means A NetBackup process timed out while connecting to another NetBackup process. Common causes include name-resolution errors, a…
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IBM TSM (ADSM) Backup: ANS1017E TCP/IP Connection Failure
ANS1017E (RC-50) Session rejected: TCP/IP connection failure is a client-side message used by IBM Tivoli Storage Manager, now IBM Storage Protect. It tells you the session could not be established or continued, but it does not by itself identify the cause. The server activity log at the same timestamp is usually the best place to…
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ORA-01861: Using Date Formats in RMAN SET UNTIL TIME
During point-in-time recovery, RMAN can report ORA-01861: literal does not match format string when the value supplied to SET UNTIL TIME does not match the session’s date format. The reliable fix Use an explicit TO_DATE expression with a matching format mask. This makes the recovery script independent of the current NLS_DATE_FORMAT setting. In RMAN, the…
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EXP-00003: No Storage Definition Found for Segment
EXP-00003: no storage definition found for segment is raised by Oracle’s legacy Export utility when it cannot obtain the storage definition for a table, index, or cluster. On older releases, a common trigger was running an exp executable whose patch level did not match the source database. First checks Record the full export log, including…
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Oracle Bind Variable Peeking and Plan Instability
Bind variables improve cursor sharing, but a plan chosen for one bind value can perform poorly for another. Oracle calls the first-value optimization behavior bind variable peeking. How peeking affects a plan During a hard parse, the optimizer can inspect the current bind values and estimate selectivity as though literals were present. This helps when…