Remove the redundant code that do more scrub eviction for disagg

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    • Storage Engines, Storage Engines - Transactions
    • SE Transactions - 2025-11-07
    • 1

      We already turn all the dirty eviction in disagg to be scrub eviction because we cannot evict a page until it is materialized. Therefore, the following code is now obsolete and can be removed:

          /*
     * Configure scrub - which reinstates clean equivalents of reconciled dirty pages. This is
     * useful because an evicted dirty page isn't necessarily a good proxy for knowing if the page
     * will be accessed again soon. Be more aggressive about scrubbing in disaggregated storage
     * because the cost of retrieving a recently reconciled page is higher in that configuration. In
     * the local storage case scrub dirty pages and keep them in cache if we are less than half way
     * to the clean, dirty and updates triggers.
     *
     * There's an experimental flag WT_CACHE_PREFER_SCRUB_EVICTION that can be turned on to enable
     * scrub eviction as long as cache usage overall is under half way to the trigger limit.
     */
    if (__wt_conn_is_disagg(session) && bytes_inuse < (uint64_t)(trigger * bytes_max) / 100)
        LF_SET(WT_EVICT_CACHE_SCRUB);

            Assignee:
            Chenhao Qu
            Reporter:
            Chenhao Qu
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              Created:
              Updated:
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