fix: paginate reading log query when no shelf is selected

[AhmedxSaid]

Problem

When a user views their reading log without selecting a specific shelf (the "All" view), get_sorted_reading_log_books() in bookshelves.py overwrites the query with one that has no LIMIT or OFFSET:

if not bookshelf_id:
    query = "SELECT * from bookshelves_books WHERE username=$username"
    # XXX Removing limit, offset, etc from data looks like a bug
    # unrelated / not fixing in this PR.
    query_params = {"username": username}

This fetches every book the user has ever logged into memory at once, then passes all those keys to a Solr get_many call. For power users with thousands of books this causes significant memory pressure and slow/failed page loads — and gets worse as their library grows.

The total_results calculation also had a related bug: shelf_totals.get(bookshelf_id, 0) returns 0 when bookshelf_id is falsy, so pagination controls showed incorrect totals.

Fix

• Add LIMIT $limit OFFSET $offset to the unbounded query, preserving the existing limit/offset from query_params
• Fix total_results to sum across all shelves when no specific shelf is selected

Test plan

• View reading log "All" tab as a user with many books — verify only one page loads
• Paginate through the reading log — verify correct pages are returned
• View a specific shelf — verify existing behavior unchanged
• Verify total book count shown in pagination is correct for the "All" view

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[mekarpeles]

Thank you for submitting this PR, @AhmedxSaid!

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Possible improvements for this PR

• No issue reference — for non-trivial logic changes, please link the related GitHub issue (e.g. Closes #1234) so reviewers have the full context on why the change is needed.
• Test cases — the change touches substantive logic in bookshelves.py but no test files are included. Consider adding or updating automated tests to cover the pagination and total count behavior.
• Proof of testing — the test plan checkboxes are all unchecked. Please fill them in with your actual results, or add a brief note describing what you ran and what you observed.

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• PR description — not empty; explains what the change does and how to verify it
• References an issue — PR body contains a #NNN reference
  • Linked issue is triaged — has a Priority: * label (not just Needs: Triage)
  • Linked issue is assigned — has at least one assignee
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Note

This comment was automatically generated by Pam, Open Library's Project AI Manager, on behalf of @mekarpeles. Pam is designed to provide status visibility, perform basic project management functions and relevant codebase research, and provide actionable feedback so contributors aren't left waiting.

[Copilot]

Pull request overview

Fixes performance and pagination correctness for the “All” (no-shelf-selected) reading log view by ensuring the DB query remains paginated and totals reflect all shelves.

Changes:

• Add ORDER BY created … LIMIT … OFFSET … to the all-shelves bookshelves_books query to prevent unbounded reads.
• Update total_results logic to compute totals across shelves when no specific shelf is selected.

[Copilot]

total_results = shelf_totals.get(bookshelf_id) or sum(...) will return the sum of all shelves whenever the selected shelf count is 0 or missing from shelf_totals (e.g., a user has no books on that shelf). That makes pagination totals incorrect for empty shelves. Consider branching on bookshelf_id (all-shelves vs specific shelf) and using a default of 0 for the specific-shelf case instead of relying on truthiness.

Suggested change

	total_results = shelf_totals.get(bookshelf_id) or sum(shelf_totals.values())
	if not bookshelf_id:
	total_results = sum(shelf_totals.values())
	else:
	total_results = shelf_totals.get(bookshelf_id, 0)

[Copilot]

In the all-shelves branch this query uses SELECT *, but downstream only relies on work_id, created, and edition_id. Selecting only the needed columns would reduce DB I/O and memory use, and keeps this query consistent with the shelf-specific query above.

Suggested change

	"SELECT * from bookshelves_books WHERE username=$username "
	"SELECT work_id, created, edition_id from bookshelves_books WHERE username=$username "