Amazon DynamoDB 是否支持 HTTP/2？
Does Amazon DynamoDB supports HTTP/2?
根据https://github.com/aws/aws-sdk-go/issues/2984，Amazon DynamoDB 似乎不支持HTTP/2。还有其他服务支持 HTTP/2 但不支持 Amazon DynamoDB。
我测试了 https://docs.aws.amazon.com/general/latest/gr/ddb.html 列表中的几个端点，但它们似乎不支持它。
$ curl -v --http2-prior-knowledge https://dynamodb.us-east-1.amazonaws.com
* Trying 52.119.233.242:443...
* TCP_NODELAY set
* Connected to dynamodb.us-east-1.amazonaws.com (52.119.233.242) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use http/1.1
* Server certificate:
* subject: CN=dynamodb.us-east-1.amazonaws.com
* start date: Dec 9 00:00:00 2020 GMT
* expire date: Dec 8 23:59:59 2021 GMT
* subjectAltName: host "dynamodb.us-east-1.amazonaws.com" matched cert's "dynamodb.us-east-1.amazonaws.com"
* issuer: C=US; O=Amazon; OU=Server CA 1B; CN=Amazon
* SSL certificate verify ok.
> GET / HTTP/1.1
> Host: dynamodb.us-east-1.amazonaws.com
> User-Agent: curl/7.68.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Server
< Date: Fri, 13 Aug 2021 23:03:18 GMT
< Content-Type: text/plain
< Content-Length: 42
< Connection: keep-alive
< x-amzn-RequestId: B0M1S6B7509A9FS62EMN7MV8QJVV4KQNSO5AEMVJF66Q9ASUAAJG
< x-amz-crc32: 3128867991
<
* Connection #0 to host dynamodb.us-east-1.amazonaws.com left intact
有谁知道这是不是真的，或者为什么他们不支持它？
在他们的文档中找不到它。
DynamoDB 今天似乎确实不支持 HTTP/2。我认为没有充分的理由“为什么”。这只是亚马逊没有做的事情，我猜他们 将来会 做，因为他们的许多其他服务以及他们的图书馆都支持 HTTP/2 .
一年多以前，我写了 a blog post 比较 DynamoDB API 和 Cassandra 和 Scylla 的 CQL API。我提到的 DynamoDB API 的缺点之一就是缺少 HTTP/2 支持，这意味着您需要打开与要发出的并发请求数一样多的连接，这会产生开销.我是这么说的：
The DynamoDB API had to work around its transport’s lack of multiplexing by adding special multi-request operations, namely BatchGetItem and BatchWriteItem — each can perform multiple operations and return reordered responses. However, these workarounds are more limited and less convenient than generic support for multiplexing.
Had DynamoDB supported HTTP/2, it would have gained multiplexing as well, and would even gain an advantage over CQL for large requests or responses: The CQL protocol cannot break up a single request or response into chunks, but HTTP/2 does do it, avoiding large latencies for small requests which happen to follow a large request on the same connection. We predict that in the future, DynamoDB will support HTTP/2. Some other Amazon services already do.
根据https://github.com/aws/aws-sdk-go/issues/2984，Amazon DynamoDB 似乎不支持HTTP/2。还有其他服务支持 HTTP/2 但不支持 Amazon DynamoDB。
我测试了 https://docs.aws.amazon.com/general/latest/gr/ddb.html 列表中的几个端点，但它们似乎不支持它。
$ curl -v --http2-prior-knowledge https://dynamodb.us-east-1.amazonaws.com
* Trying 52.119.233.242:443...
* TCP_NODELAY set
* Connected to dynamodb.us-east-1.amazonaws.com (52.119.233.242) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use http/1.1
* Server certificate:
* subject: CN=dynamodb.us-east-1.amazonaws.com
* start date: Dec 9 00:00:00 2020 GMT
* expire date: Dec 8 23:59:59 2021 GMT
* subjectAltName: host "dynamodb.us-east-1.amazonaws.com" matched cert's "dynamodb.us-east-1.amazonaws.com"
* issuer: C=US; O=Amazon; OU=Server CA 1B; CN=Amazon
* SSL certificate verify ok.
> GET / HTTP/1.1
> Host: dynamodb.us-east-1.amazonaws.com
> User-Agent: curl/7.68.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Server
< Date: Fri, 13 Aug 2021 23:03:18 GMT
< Content-Type: text/plain
< Content-Length: 42
< Connection: keep-alive
< x-amzn-RequestId: B0M1S6B7509A9FS62EMN7MV8QJVV4KQNSO5AEMVJF66Q9ASUAAJG
< x-amz-crc32: 3128867991
<
* Connection #0 to host dynamodb.us-east-1.amazonaws.com left intact
有谁知道这是不是真的，或者为什么他们不支持它？ 在他们的文档中找不到它。
DynamoDB 今天似乎确实不支持 HTTP/2。我认为没有充分的理由“为什么”。这只是亚马逊没有做的事情，我猜他们 将来会 做，因为他们的许多其他服务以及他们的图书馆都支持 HTTP/2 .
一年多以前，我写了 a blog post 比较 DynamoDB API 和 Cassandra 和 Scylla 的 CQL API。我提到的 DynamoDB API 的缺点之一就是缺少 HTTP/2 支持，这意味着您需要打开与要发出的并发请求数一样多的连接，这会产生开销.我是这么说的：
The DynamoDB API had to work around its transport’s lack of multiplexing by adding special multi-request operations, namely
BatchGetItemandBatchWriteItem— each can perform multiple operations and return reordered responses. However, these workarounds are more limited and less convenient than generic support for multiplexing. Had DynamoDB supported HTTP/2, it would have gained multiplexing as well, and would even gain an advantage over CQL for large requests or responses: The CQL protocol cannot break up a single request or response into chunks, but HTTP/2 does do it, avoiding large latencies for small requests which happen to follow a large request on the same connection. We predict that in the future, DynamoDB will support HTTP/2. Some other Amazon services already do.