> ## Documentation Index
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> Use this file to discover all available pages before exploring further.
> Seamlessly connect your object storage to ClickHouse Cloud.
# Integrating Google Cloud Storage with ClickHouse Cloud
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The GCS ClickPipe provides a fully-managed and resilient way to ingest data from Google Cloud Storage (GCS). It supports both **one-time** and **continuous ingestion** with exactly-once semantics.
GCS ClickPipes can be deployed and managed manually using the ClickPipes UI, as well as programmatically using [OpenAPI](/integrations/clickpipes/programmatic-access/openapi) and [Terraform](/integrations/clickpipes/programmatic-access/terraform).
* [JSON](/reference/formats/JSON/JSON)
* [CSV](/reference/formats/CSV/CSV)
* [TSV](/reference/formats/TabSeparated/TabSeparated)
* [Parquet](/reference/formats/Parquet/Parquet)
* [Avro](/reference/formats/Avro/Avro)
Features
One-time ingestion
By default, the GCS ClickPipe will load all files matched by a pattern from the specified bucket into the ClickHouse destination table in a single batch operation. Once the ingestion task completes, the ClickPipe stops automatically. This one-time ingestion mode provides exactly-once semantics, ensuring that each file is processed reliably without duplicates.
Continuous ingestion
When continuous ingestion is enabled, ClickPipes continuously ingests data from the specified path. To determine ingestion order, the GCS ClickPipe relies on the implicit [lexicographical order](#continuous-ingestion-lexicographical-order) of files, by default. It can also be configured to ingest files in [any order](#continuous-ingestion-any-order) using a [Google Cloud Pub/Sub](https://cloud.google.com/pubsub) subscription [configured to provide notifications for the bucket](https://docs.cloud.google.com/storage/docs/reporting-changes#command-line).
Lexicographical order
The GCS ClickPipe assumes files are added to a bucket in lexicographical order, and relies on this implicit order to ingest files sequentially. This means that any new file **must** be lexically greater than the last ingested file. For example, files named `file1`, `file2`, and `file3` will be ingested sequentially, but if a new `file 0` is added to the bucket, it will be **ignored** because the file name isn't lexically greater than the last ingested file.
In this mode, the GCS ClickPipe does an initial load of **all files** in the specified path, and then polls for new files at a configurable interval (by default, 30 seconds). It is **not possible** to start ingestion from a specific file or point in time — ClickPipes will always load all files in the specified path.
Any order
See [Configuring unordered mode for continuous ingestion](/integrations/clickpipes/object-storage/google-cloud-storage/unordered-mode) for step-by-step instructions.
It's possible to configure a GCS ClickPipe to ingest files that don't have an implicit order by setting up a [Google Cloud Pub/Sub](https://docs.cloud.google.com/storage/docs/pubsub-notifications) subscription that receives notifications from the bucket. This allows ClickPipes to listen for object created events and ingest any new files regardless of the file naming convention.
Unordered mode is **not** supported for public buckets. It requires **Service Account** authentication and a [Google Cloud Pub/Sub](https://cloud.google.com/pubsub) subscription connected to the bucket.
In this mode, the GCS ClickPipe does an initial load of **all files** in the selected path, and then listens for `OBJECT_FINALIZE` notifications via the Pub/Sub subscription that match the specified path. Any message for a previously seen file, file not matching the path, or event of a different type will be **ignored**. It is **not possible** to start ingestion from a specific file or point in time — ClickPipes will always load all files in the selected path.
File pattern matching
Object Storage ClickPipes follow the POSIX standard for file pattern matching. All patterns are **case-sensitive** and match the **full path** after the bucket name. For better performance, use the most specific pattern possible (e.g., `data-2024-*.csv` instead of `*.csv`).
Supported patterns
| Pattern | Description | Example | Matches |
| --------------------- | ------------------------------------------------------------------------------------------- | ------------------- | ----------------------------------------------------------------- |
| `?` | Matches exactly **one** character (excluding `/`) | `data-?.csv` | `data-1.csv`, `data-a.csv`, `data-x.csv` |
| `*` | Matches **zero or more** characters (excluding `/`) | `data-*.csv` | `data-1.csv`, `data-001.csv`, `data-report.csv`, `data-.csv` |
| `**`
Recursive | Matches **zero or more** characters (including `/`). Enables recursive directory traversal. | `logs/**/error.log` | `logs/error.log`, `logs/2024/error.log`, `logs/2024/01/error.log` |
**Examples:**
* `https://bucket.s3.amazonaws.com/folder/*.csv`
* `https://bucket.s3.amazonaws.com/logs/**/data.json`
* `https://bucket.s3.amazonaws.com/file-?.parquet`
* `https://bucket.s3.amazonaws.com/data-2024-*.csv.gz`
Unsupported patterns
| Pattern | Description | Example | Alternatives |
| ----------- | ------------------------------ | ---------------------- | ----------------------------------------- |
| `{abc,def}` | Brace expansion - alternatives | `{logs,data}/file.csv` | Create separate ClickPipes for each path. |
| `{N..M}` | Numeric range expansion | `file-{1..100}.csv` | Use `file-*.csv` or `file-?.csv`. |
**Examples:**
* `https://bucket.s3.amazonaws.com/{documents-01,documents-02}.json`
* `https://bucket.s3.amazonaws.com/file-{1..100}.csv`
* `https://bucket.s3.amazonaws.com/{logs,metrics}/data.parquet`
Exactly-once semantics
Various types of failures can occur when ingesting large dataset, which can result in a partial inserts or duplicate data. Object Storage ClickPipes are resilient to insert failures and provides exactly-once semantics. This is accomplished by using temporary "staging" tables. Data is first inserted into the staging tables. If something goes wrong with this insert, the staging table can be truncated and the insert can be retried from a clean state. Only when an insert is completed and successful, the partitions in the staging table are moved to target table. To read more about this strategy, check-out [this blog post](https://clickhouse.com/blog/supercharge-your-clickhouse-data-loads-part3).
Virtual columns
To track which files have been ingested, include the `_file` virtual column to the column mapping list. The `_file` virtual column contains the filename of the source object, which can be used to query which files have been processed.
Access control
Permissions
The GCS ClickPipe supports public and private buckets. [Requester Pays](https://docs.cloud.google.com/storage/docs/requester-pays) buckets are **not** supported.
GCS bucket
The service account used by ClickPipes must allow the following actions at the bucket level:
* [`roles/storage.objectViewer`](https://docs.cloud.google.com/storage/docs/access-control/iam-roles#storage.objectViewer)
This role contains the [`storage.objects.list`](https://docs.cloud.google.com/storage/docs/json_api/v1/objects/list) and [\`storage.objects.get](https://docs.cloud.google.com/storage/docs/json_api/v1/objects/get#required-permissions) IAM permissions, which allow ClickPipes to list and fetch objects in the specified bucket.
Pub/Sub subscription
When using [unordered mode](#continuous-ingestion-any-order), the service account must have the following roles on the Pub/Sub subscription:
* [`roles/pubsub.subscriber`](https://cloud.google.com/pubsub/docs/access-control#roles) — to receive and acknowledge messages.
* [`roles/pubsub.viewer`](https://cloud.google.com/pubsub/docs/access-control#roles) — to get subscription metadata.
Authentication
Service account
Service Account authentication is required when using [unordered mode](#continuous-ingestion-any-order) with Pub/Sub notifications. Select **Service Account** as the authentication method and upload the service account key JSON file.
HMAC credentials
To use [HMAC keys](https://docs.cloud.google.com/storage/docs/authentication/hmackeys) to authenticate, choose `Credentials` under **Authentication method** when setting up your ClickPipe connection. Then, provide the access key (e.g., `GOOGTS7C7FUP3AIRVJTE2BCDKINBTES3HC2GY5CBFJDCQ2SYHV6A6XXVTJFSA`) and secret key (e.g., `bGoa+V7g/yqDXvKRqq+JTFn4uQZbPiQJo4pf9RzJ`) under `Access key` and `Secret key`, respectively.
Follow [this guide](/integrations/connectors/data-sources/gcs#create-a-service-account-hmac-key-and-secret) to create a service account with an HMAC key.
Network access
GCS ClickPipes use two distinct network paths for metadata discovery and data ingestion: the ClickPipes service and the ClickHouse Cloud service, respectively. If you want to configure an additional layer of network security (e.g., for compliance reasons), network access **must be configured for both paths**.
* For **IP-based access control**, the [IP filtering rules](https://docs.cloud.google.com/storage/docs/ip-filtering-overview) for your GCS bucket must allow the static IPs for the ClickPipes service region listed [here](/integrations/clickpipes/home#list-of-static-ips), as well as the [static IPs](/products/cloud/guides/data-sources/cloud-endpoints-api) for the ClickHouse Cloud service. To obtain the static IPs for your ClickHouse Cloud region, open a terminal and run:
```bash theme={null}
# Replace with your ClickHouse Cloud region
curl -s https://api.clickhouse.cloud/static-ips.json | jq -r '.gcp[] | select(.region == "") | .egress_ips[]'
```
Advanced settings
ClickPipes provides sensible defaults that cover the requirements of most use cases. If your use case requires additional fine-tuning, you can adjust the following settings:
| Setting | Default value | Description |
| ------------------------------------ | ------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| `Max insert bytes` | 10GB | Number of bytes to process in a single insert batch. |
| `Max file count` | 100 | Maximum number of files to process in a single insert batch. |
| `Max threads` | auto(3) | [Maximum number of concurrent threads](/reference/settings/session-settings#max_threads) for file processing. |
| `Max insert threads` | 1 | [Maximum number of concurrent insert threads](/reference/settings/session-settings#max_insert_threads) for file processing. |
| `Min insert block size bytes` | 1GB | [Minimum size of bytes in the block](/reference/settings/session-settings#min_insert_block_size_bytes) which can be inserted into a table. |
| `Max download threads` | 4 | [Maximum number of concurrent download threads](/reference/settings/session-settings#max_download_threads). |
| `Object storage polling interval` | 30s | Configures the maximum wait period before inserting data into the ClickHouse cluster. |
| `Parallel distributed insert select` | 2 | [Parallel distributed insert select setting](/reference/settings/session-settings#parallel_distributed_insert_select). |
| `Parallel view processing` | false | Whether to enable pushing to attached views [concurrently instead of sequentially](/reference/settings/session-settings#parallel_view_processing). |
| `Use cluster function` | true | Whether to process files in parallel across multiple nodes. |
Scaling
Object Storage ClickPipes are scaled based on the minimum ClickHouse service size determined by the [configured vertical autoscaling settings](/products/cloud/features/autoscaling/vertical#configuring-vertical-auto-scaling). The size of the ClickPipe is determined when the pipe is created. Subsequent changes to the ClickHouse service settings won't affect the ClickPipe size.
To increase the throughput on large ingest jobs, we recommend scaling the ClickHouse service before creating the ClickPipe.
Known limitations
File size
ClickPipes will only attempt to ingest objects that are **10GB or smaller** in size. If a file is greater than 10GB, an error will be appended to the ClickPipes dedicated error table.
Compatibility
The GCS ClickPipe uses on the Cloud Storage [XML API](https://docs.cloud.google.com/storage/docs/interoperability) for interoperability, which requires using the `https://storage.googleapis.com/` bucket prefix (instead of `gs://`) and using [HMAC keys](https://docs.cloud.google.com/storage/docs/authentication/hmackeys) for authentication.
View support
Materialized views on the target table are also supported. ClickPipes will create staging tables not only for the target table, but also any dependent materialized view.
We don't create staging tables for non-materialized views. This means that if you have a target table with one of more downstream materialized views, those materialized views should avoid selecting data via a view from the target table. Otherwise, you may find that you're missing data in the materialized view.