Kqr Row Cache Contention Check Gets -

To understand kqr row cache contention check gets , we must first break down the acronym:

). This cache stores object definitions, such as table structures, column information, and sequence values, as individual rows rather than data blocks. Understanding Row Cache Contention

— KQR’s row cache for item:42 expired. 9:00:02 — 10,000 concurrent GET requests arrived simultaneously. kqr row cache contention check gets

The "kqr row cache contention check gets" comes into play during step 3–4 when:

Contention is typically identified by high wait times for events like latch: row cache objects row cache lock Oracle Forums Hot Buckets and "Check Gets" To understand kqr row cache contention check gets

While not a cure-all, an undersized Shared Pool can lead to frequent aging out of row cache entries, forcing expensive re-loads.

kqr row cache contention check gets = CRITICAL The Library Cache typically uses a hashing mechanism

Oracle uses Latches to protect memory structures. The Library Cache typically uses a hashing mechanism to spread load across many "child latches." However, the Row Cache has historically been less granular. It is protected by a smaller number of latches (often referred to as row cache objects latches).

Because the cache was empty, all 10,000 threads saw a at the exact same moment. They all rushed to the database.

SELECT substr(cache_name,1,20) cache_name, substr(key,1,60) key, state, count(*) usage FROM v$rowcache_parent GROUP BY cache_name, key, state ORDER BY usage DESC;