https://www.memcp.org/index.php?action=history&feed=atom&title=Memory_Management_and_Eviction 2026-08-25T10:00:07Z Revision history for this page on the wiki MediaWiki 1.39.1 https://www.memcp.org/index.php?title=Memory_Management_and_Eviction&diff=266&oldid=prev 2026-08-21T11:02:20Z

<p>Created page with &quot;MemCP tracks persisted shard columns, indexes, temporary columns, keytables, cache-engine objects, and string dictionaries in a global memory manager. The overall budget defaults to 50% of system RAM. A separate persisted-data budget defaults to 30%. Exact byte limits override percentages. If system available memory falls too low, MemCP can evict before its own configured budget is exhausted. Eviction is LRU-like and type-aware. Persistent shard eviction releases only...&quot;</p> <p><b>New page</b></p><div>MemCP tracks persisted shard columns, indexes, temporary columns, keytables, cache-engine objects, and string dictionaries in a global memory manager.<br /> <br /> The overall budget defaults to 50% of system RAM. A separate persisted-data budget defaults to 30%. Exact byte limits override percentages. If system available memory falls too low, MemCP can evict before its own configured budget is exhausted.<br /> <br /> Eviction is LRU-like and type-aware. Persistent shard eviction releases only in-memory representations; files remain and are reloaded on demand. Shards with unflushed deltas cannot be evicted. &lt;code&gt;memory&lt;/code&gt; tables are never evicted because that would destroy their only copy. &lt;code&gt;cache&lt;/code&gt; tables are explicitly reconstructible and may be discarded under pressure.<br /> <br /> Monitor both current/budgeted memory and reload behavior. A workload whose hot set exceeds the budget remains correct for persistent tables but may become storage-I/O bound. See [[Settings]] and [[Dashboard_and_Operations|Dashboard and Operations]].</div>

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