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archlab 1.0 gantt
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title "Order store migration"
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description "Moving orders off the legacy store, and what blocks what"
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starts 2026-09-07
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@gantt
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section "Prepare"
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task audit "Schema audit" 5d done at 0
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desc "Read every column, write down what actually moves and what is dead."
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task shadow "Shadow writes" 13d active after audit
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desc "Write to both stores. The long pole, and the reason the cut-over date is what it is."
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task backfill "Historical backfill" 12d active after audit
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desc "Copy the history across. Has a day of float, so a slip here costs nothing."
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task verify "Verify parity" 6d at-risk after shadow, backfill
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desc "Compare both stores row by row. At risk: the comparison tool is not written yet."
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milestone parity "Parity signed off" after verify
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section "Cut over"
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task freeze "Freeze writes" 2d after verify
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desc "Reject writes to the legacy store. The only irreversible step."
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task cutover "Point traffic over" 3d after freeze
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milestone live "Traffic on new store" after cutover
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section "Retire"
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task dualread "Dual-read off" 4d after cutover
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task drop "Drop legacy tables" 6d after dualread
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desc "The end of the chain, and the date the whole plan is measured against."
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task archive "Archive dumps" 5d after cutover
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desc "Independent of the retirement chain, so it carries float and sinks below it."
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