Add adaptive alert noise suppression with scoring and dedup windows

alembic/versions/003_add_alert_noise_suppression.py

@@ -0,0 +1,60 @@
+"""Add alert noise suppression — AlertNoiseRecord table + severity column on AlertLog.
+
+Revision ID: 003_add_alert_noise_suppression
+Revises: 81c7c80e0f60
+Create Date: 2026-04-11
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "003_add_alert_noise_suppression"
+down_revision: Union[str, Sequence[str], None] = "81c7c80e0f60"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Add severity column to existing alert_logs table
+    op.add_column(
+        "alert_logs",
+        sa.Column("severity", sa.String(length=20), nullable=True),
+    )
+
+    # Create the alert_noise_records table
+    op.create_table(
+        "alert_noise_records",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("table_name", sa.String(length=255), nullable=False),
+        sa.Column("alert_type", sa.String(length=50), nullable=False),
+        sa.Column("count_1h", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("count_24h", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("count_7d", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("noise_score", sa.Float(), nullable=False, server_default="0.0"),
+        sa.Column("severity_trend", sa.String(length=20), nullable=False, server_default="stable"),
+        sa.Column("is_throttled", sa.Boolean(), nullable=False, server_default="false"),
+        sa.Column("last_calculated_at", sa.DateTime(), nullable=True),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("table_name", "alert_type", name="uq_noise_table_type"),
+    )
+    op.create_index(
+        "ix_alert_noise_records_table_name",
+        "alert_noise_records",
+        ["table_name"],
+    )
+    op.create_index(
+        "ix_alert_noise_records_alert_type",
+        "alert_noise_records",
+        ["alert_type"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_alert_noise_records_alert_type", table_name="alert_noise_records")
+    op.drop_index("ix_alert_noise_records_table_name", table_name="alert_noise_records")
+    op.drop_table("alert_noise_records")
+    op.drop_column("alert_logs", "severity")