Measured 2000-product sync_all() at ~2.5 products/sec baseline (2-core/8GB
staging box). Confirmed via source inspection that WooCommerce's
wc_product_meta_lookup sync is synchronous inside WC_Product::save(), so
every product save was its own implicit autocommit transaction -> its own
fsync. Batching each 200-item chunk into one explicit transaction, deferring
product_cat term counting, suspending post cache invalidation for the
duration, and caching subject->term_id lookups in memory brings the same
2000-item sync to ~21 products/sec (~95s), with the update-path re-run at
~82/sec.
Verified correctness after, not just speed: wc_product_meta_lookup price/
stock matched postmeta exactly (0 mismatches across all 2000), product_cat
term counts matched actual term_relationships (0 mismatches), no orphaned
category assignments, no duplicate products on re-run.
twooey
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