77 lines
2.6 KiB
Python
77 lines
2.6 KiB
Python
"""Phase 12: Add performance indexes on high-filter columns
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Revision ID: phase12_performance_indexes
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Revises: phase11_director_role
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Create Date: 2026-04-25
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Rationale
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---------
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The following columns are filtered or ordered on every page load but had no
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DB index, causing full table scans as row counts grow:
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inspections
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- status — filtered on list/dashboard/SLA queries
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- facility_id — filtered for customer-scoped views and reports
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- inspector_id — filtered for inspector-scoped views
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- inspection_date — used in all trend/score queries (ORDER BY, range filter)
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issues
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- status — filtered on every issues list/dashboard load
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- severity — filtered in dashboard breakdown and issues list
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- assigned_to — filtered for inspector-scoped views
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- reported_at — used for ordering
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Existence checks use information_schema so the migration is safe to re-run
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on any MySQL version (compatible back to 5.7).
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"""
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from alembic import op
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from sqlalchemy import text
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def _index_exists(conn, table: str, index_name: str) -> bool:
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"""Return True if the named index already exists on the given table."""
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result = conn.execute(text(
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"SELECT COUNT(*) FROM information_schema.statistics "
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"WHERE table_schema = DATABASE() "
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" AND table_name = :table "
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" AND index_name = :index"
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), {'table': table, 'index': index_name})
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return result.scalar() > 0
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revision = 'phase12_performance_indexes'
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down_revision = 'phase11_director_role'
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branch_labels = None
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depends_on = None
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# (table, index_name, column)
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INDEXES = [
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('inspections', 'ix_inspections_status', 'status'),
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('inspections', 'ix_inspections_facility_id', 'facility_id'),
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('inspections', 'ix_inspections_inspector_id', 'inspector_id'),
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('inspections', 'ix_inspections_inspection_date', 'inspection_date'),
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('issues', 'ix_issues_status', 'status'),
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('issues', 'ix_issues_severity', 'severity'),
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('issues', 'ix_issues_assigned_to', 'assigned_to'),
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('issues', 'ix_issues_reported_at', 'reported_at'),
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]
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def upgrade():
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conn = op.get_bind()
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for table, index_name, column in INDEXES:
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if not _index_exists(conn, table, index_name):
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op.execute(text(
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f'CREATE INDEX {index_name} ON {table} ({column})'
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))
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def downgrade():
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conn = op.get_bind()
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for table, index_name, _column in INDEXES:
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if _index_exists(conn, table, index_name):
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op.execute(text(
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f'DROP INDEX {index_name} ON {table}'
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)) |