From b65d063b4b04d7237c183415f7f6578a2be9e733 Mon Sep 17 00:00:00 2001
From: Konstantin Prokopenko <kprokopenko@users.noreply.github.com>
Date: Wed, 8 Apr 2026 12:27:42 +0300
Subject: [PATCH] feat(changefeed): add initial_scan to ydb_table_changefeed

Add optional initial_scan (default false, ForceNew) to match YDB CDC
ALTER TABLE ADD CHANGEFEED WITH (INITIAL_SCAN = TRUE).

DescribeTable does not return this flag; refresh keeps the configured
value in state to avoid spurious drift.

Fixes ydb-platform/terraform-provider-ydb#52

Made-with: Cursor
---
 internal/resources/changefeed/changefeed.go |  6 ++++
 internal/resources/changefeed/yql.go        |  4 +++
 internal/resources/changefeed/yql_test.go   | 31 +++++++++++++++++++++
 sdk/terraform/table/changefeed/resource.go  |  8 ++++++
 4 files changed, 49 insertions(+)
 create mode 100644 internal/resources/changefeed/yql_test.go

diff --git a/internal/resources/changefeed/changefeed.go b/internal/resources/changefeed/changefeed.go
index 068a23c..6ba6459 100644
--- a/internal/resources/changefeed/changefeed.go
+++ b/internal/resources/changefeed/changefeed.go
@@ -37,6 +37,7 @@ type changeDataCaptureSettings struct {
 	Format            *string
 	RetentionPeriod   *string
 	VirtualTimestamps *bool
+	InitialScan       bool
 	Entity            *helpers.YDBEntity
 	TableEntity       *helpers.YDBEntity
 	Consumers         []topictypes.Consumer
@@ -128,6 +129,7 @@ func changefeedResourceSchemaToChangefeedResource(d *schema.ResourceData) (*chan
 	if retentionPeriod, ok := d.Get("retention_period").(string); ok && retentionPeriod != "" {
 		settings.RetentionPeriod = &retentionPeriod
 	}
+	settings.InitialScan = d.Get("initial_scan").(bool)
 	settings.Consumers = expandConsumers(d)
 
 	return settings, nil
@@ -167,6 +169,10 @@ func flattenCDCDescription(
 	if err != nil {
 		return
 	}
+	err = d.Set("initial_scan", changefeedResource.InitialScan)
+	if err != nil {
+		return
+	}
 
 	curConsRaw := d.Get("consumer")
 	cons := helpers.ConsumerSort(curConsRaw, consumers)
diff --git a/internal/resources/changefeed/yql.go b/internal/resources/changefeed/yql.go
index d5de092..0678605 100644
--- a/internal/resources/changefeed/yql.go
+++ b/internal/resources/changefeed/yql.go
@@ -36,6 +36,10 @@ func PrepareCreateRequest(cdc *changeDataCaptureSettings) string {
 		buf = helpers.AppendWithEscape(buf, *cdc.RetentionPeriod)
 		buf = append(buf, '"', ')')
 	}
+	if cdc.InitialScan {
+		buf = append(buf, ',', '\n')
+		buf = append(buf, "INITIAL_SCAN = TRUE"...)
+	}
 	buf = append(buf, '\n', ')')
 	return string(buf)
 }
diff --git a/internal/resources/changefeed/yql_test.go b/internal/resources/changefeed/yql_test.go
new file mode 100644
index 0000000..870c61c
--- /dev/null
+++ b/internal/resources/changefeed/yql_test.go
@@ -0,0 +1,31 @@
+package changefeed
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPrepareCreateRequest_initialScan(t *testing.T) {
+	format := "JSON"
+	t.Run("omits when false", func(t *testing.T) {
+		q := PrepareCreateRequest(&changeDataCaptureSettings{
+			TablePath:   "my/table",
+			Name:        "cf1",
+			Mode:        "UPDATES",
+			Format:      &format,
+			InitialScan: false,
+		})
+		require.NotContains(t, q, "INITIAL_SCAN")
+	})
+	t.Run("includes when true", func(t *testing.T) {
+		q := PrepareCreateRequest(&changeDataCaptureSettings{
+			TablePath:   "my/table",
+			Name:        "cf1",
+			Mode:        "UPDATES",
+			Format:      &format,
+			InitialScan: true,
+		})
+		require.Contains(t, q, "INITIAL_SCAN = TRUE")
+	})
+}
diff --git a/sdk/terraform/table/changefeed/resource.go b/sdk/terraform/table/changefeed/resource.go
index 5759912..1180d30 100644
--- a/sdk/terraform/table/changefeed/resource.go
+++ b/sdk/terraform/table/changefeed/resource.go
@@ -164,6 +164,14 @@ func ResourceSchema() map[string]*schema.Schema {
 			Optional:    true,
 			ForceNew:    true,
 		},
+		"initial_scan": {
+			Type:     schema.TypeBool,
+			Optional: true,
+			Default:  false,
+			ForceNew: true,
+			Description: "When true, runs an [initial snapshot scan](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/changefeed) of the table when the changefeed is created. " +
+				"Only applies at creation; YDB does not expose this flag on describe, so Terraform keeps the configured value in state.",
+		},
 		"retention_period": {
 			Type:         schema.TypeString,
 			Description:  "Time of data retention in the topic, [ISO 8601](https://ru.wikipedia.org/wiki/ISO_8601) format.",