supastash/dist/utils/createIndexes.js

Offline-first sync engine for Supabase in React Native using SQLite

import { getSupastashDb } from "../db/dbInitializer";
import { logError } from "./logs";
import { getAllTables } from "./sync/getAllTables";
/**
 * Create a single-column index on "id" where it actually helps.
 * - Skips virtual tables (e.g. FTS), views, system tables.
 * - Skips when "id" doesn't exist.
 * - Skips when "id" is already PK (including TEXT PK which has an implicit unique index).
 * - Skips when there's already an index on "id".
 */
export async function createIdIndexes() {
  const db = await getSupastashDb();
  const tables = await getAllTables();
  if (!tables || !tables.length) return;
  const q = (s) => `"${s.replace(/"/g, '""')}"`;
  for (const table of tables) {
    if (!table) continue;
    try {
      // 1) Check sqlite_schema for table kind + DDL
      const schemaRow = await db.getFirstAsync(
        `SELECT type, sql FROM sqlite_schema WHERE name = ?1`,
        [table]
      );
      if (!schemaRow) continue; // not a real table in this db
      if (schemaRow.type !== "table") continue; // views, triggers, etc.
      const ddl = schemaRow.sql || "";
      // Virtual tables get skipped
      if (/\bCREATE\s+VIRTUAL\s+TABLE\b/i.test(ddl)) {
        continue;
      }
      // 2) Inspect columns; ensure "id" exists and get PK info
      const columns = await db.getAllAsync(`PRAGMA table_info(${q(table)})`);
      if (!columns?.length) continue;
      const idCol = columns.find((c) => c.name === "id");
      if (!idCol) continue; // no "id" column → nothing to do
      // If "id" is part of the PK, indexing is unnecessary/redundant:
      // - INTEGER PRIMARY KEY uses rowid (fast already).
      // - TEXT/other PRIMARY KEYs get an implicit unique index.
      const pkCols = columns.filter((c) => c.pk > 0);
      const idIsPk = idCol.pk > 0;
      if (idIsPk) {
        // If it's the only PK column or part of composite PK, skip — already indexed enough.
        continue;
      }
      // 3) Check if an index on "id" already exists
      const indexes = await db.getAllAsync(`PRAGMA index_list(${q(table)})`);
      let hasIdOnlyIndex = false;
      if (indexes?.length) {
        for (const ix of indexes) {
          // Ignore partial indexes for simplicity
          const cols = await db.getAllAsync(`PRAGMA index_info(${q(ix.name)})`);
          if (!cols?.length) continue;
          if (cols.length === 1 && cols[0].name === "id") {
            hasIdOnlyIndex = true;
            break;
          }
        }
      }
      if (hasIdOnlyIndex) continue;
      // 4) Create the index safely
      const idxName = `idx_${table}_id`;
      try {
        await db.runAsync(
          `CREATE INDEX IF NOT EXISTS ${q(idxName)} ON ${q(table)}("id");`
        );
      } catch (e) {
        await db.runAsync("ROLLBACK");
        logError(`[index-skip] ${table}: ${e.message}`);
      }
    } catch (err) {
      logError(`[index-check-failed] ${table}: ${err.message}`);
    }
  }
}