Oracle Database
A slow system needs a shortlist of statements consuming time, with execution count kept in view. Cached totals are not a historical workload report.
SQL Performance & Memory2 min read
Read article : Find cached SQL with high total elapsed time
Oracle Database
Excessive logical reads can consume CPU even when storage latency is low. Inspect per-child buffer gets with execution counts.
SQL Performance & Memory2 min read
Read article : Find logical-read-heavy Oracle SQL
Oracle Database
Slow read-heavy work may reflect a large intended scan, poor access path or storage latency. Start by identifying the cached statements involved.
SQL Performance & Memory2 min read
Read article : Inspect SQL with high physical-read totals
Oracle Database
A hypothetical plan may differ from the one the application executed. Display the correct cached child cursor when investigating a regression.
SQL Performance & Memory1 min read
Read article : Inspect a cached execution plan without running EXPLAIN PLAN
Oracle Database
A single SQL ID can have many children because its executions cannot share one cursor environment. Collect the mismatch reasons before changing caches.
SQL Performance & Memory1 min read
Read article : Investigate many child cursors for one SQL statement
Oracle Database
A parse storm can increase CPU and shared-pool pressure. Capture related counters twice rather than diagnosing from one lifetime total.
SQL Performance & Memory1 min read
Read article : Measure Oracle parse activity as interval deltas
Oracle Database
An application may issue nearly identical statements with values embedded in the text, reducing reuse and increasing parsing work.
SQL Performance & Memory2 min read
Read article : Detect many literal variants of Oracle SQL
Oracle Database
An optimizer can estimate poorly when statistics no longer represent the data. Inspect relevant table and partition statistics before gathering everything.
SQL Performance & Memory1 min read
Read article : Check optimizer statistics for the actual table and partition
Oracle Database
A query may stop using an expected index because of its state, visibility, column order or changed selectivity. Inspect metadata before rebuilding.
SQL Performance & Memory2 min read
Read article : Check whether an index is valid and visible to the optimizer
Oracle Database
Different bind values may have very different selectivity. An average execution time can hide that only a narrow input range is slow.
SQL Performance & Memory1 min read
Read article : Investigate bind-sensitive cursor behavior
Oracle Database
A shared-memory allocation error can involve fragmentation, workload churn or a specific pool. Preserve the exact pool and allocation details.
SQL Performance & Memory2 min read
Read article : ORA-04031: investigate the named shared-memory allocation failure
Oracle Database
A process can fail allocation because of OS limits, address-space constraints or excessive private memory use. Distinguish it from SGA allocation errors.
SQL Performance & Memory2 min read
Read article : ORA-04030: investigate server-process memory exhaustion