Solving Oracle Log File Sync Waits Caused by High Commit Frequency
High commit frequency is the number one cause for foreground log file sync waits in Oracle. Learn how to diagnose and tune for these waits.
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Diagnosing Oracle Wait for TM Enqueue in Mode 3
Unindexed foreign key columns are the primary cause of Oracle TM lock contention in mode 3; however, this only applies to databases prior to Oracle9i Database.
Read MoreDiagnosing Oracle Wait for TX Enqueue in Mode 4–Bitmap Index Entry
Diagnose Oracle waits for TX enqueue in mode 4 that are caused by multiple sessions attempting to update or delete different rows covered by the same bitmap entry.
Read MoreDiagnosing Oracle Wait for TX Enqueue in Mode 4–Unique Key Enforcement
Unique or primary key enforcement may cause Oracle enq: TX—row lock contention, indicating an application issue outside the database.
Read MoreDiagnosing Oracle Wait for TX Enqueue in Mode 4–ITL Shortage
Learn how to diagnose Oracle waits for TX enqueue in mode 4 that are caused by ITL (interested transaction list) shortage.
Read MoreDiagnosing Oracle Wait for TX Enqueue in Mode 6 (Row Lock Contention)
A wait for the Oracle TX enqueue in mode 6 (row lock contention) is a common enqueue wait, and occurs when a transaction tries to update or delete rows that are currently locked by another transaction.
Read MoreHow Hot Blocks in Oracle Cause Cache Buffers Chains Latches Contention
Hot blocks are a common cause of cache buffers chains latch contention and can significantly impact performance. Learn some workarounds for this.
Read MoreHow Inefficient SQL Statements in Oracle Cause Contention for Cache Buffers Chains Latches
Inefficient SQL statements are the main cause of Oracle cache buffers chains latch contentions and should be considered when performance tuning.
Read MoreHow Parsing in Oracle Causes Contention for Shared Pool and Library Cache Latches
Contentions for the shared pool and library cache latches are mainly due to intense hard parsing. Learn mroe about how this impacts performance.
Read MoreWhat Does the Oracle Latch Free Wait Event Tell You?
Oracle latch free wait events mean the process failed to obtain the latch in the willing-to-wait mode after spinning _SPIN_COUNT times and went to sleep. Learn more about what this can mean.
Read MoreHow DB_FILE_DIRECT_IO_COUNT Initialization Parameters Affect Oracle Direct Path Read Performance
The Oracle DB_FILE_DIRECT_IO_COUNT initialization parameter can impact the direct path read performance in several ways.
Read MoreWhy Oracle Physical I/Os are Expensive
Oracle physical I/O is about more than physical disks and I/O subsystem; it is also about the stuff that goes on inside when blocks are being read into the SGA.
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