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fix(datastore): Update initial ChannelPool configs according to Datastore best practice guide #12919

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Merged
lqiu96 merged 4 commits into from
Apr 24, 2026
Merged

fix(datastore): Update initial ChannelPool configs according to Datastore best practice guide #12919

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56dd1b2
fix(datastore): Update initial ChannelPool configs according to Datas…
lqiu96 Apr 24, 2026
e6b0c09
chore: Address confusing code comment
lqiu96 Apr 24, 2026
f64c7b1
chore: Fix lint
lqiu96 Apr 24, 2026
adebddc
chore: Clarify code comment to differentiate theoretical max and expe…
lqiu96 Apr 24, 2026
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19 changes: 14 additions & 5 deletions ...ore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/DatastoreOptions.java
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Original file line number Diff line number Diff line change
Expand Up @@ -53,12 +53,19 @@ public class DatastoreOptions extends ServiceOptions<Datastore, DatastoreOptions
private static final String DEFAULT_DATABASE_ID = "";
public static final String PROJECT_ID_ENV_VAR = "DATASTORE_PROJECT_ID";
public static final String LOCAL_HOST_ENV_VAR = "DATASTORE_EMULATOR_HOST";

// Default to a slightly larger channel count to handle a larger initial QPS (up to ~500 QPS as
// each channel can handle 100 max streams). This default remains a bit conservative and will

@gemini-code-assist gemini-code-assist Bot Apr 24, 2026

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medium

The comment at lines 57-58 refers to a stale implementation (~500 QPS and 100 max streams) which is inconsistent with the updated configuration. According to repository rules, comments referring to stale implementations should be removed rather than updated.

References
  1. Remove comments that refer to stale implementations instead of updating them.

@jinseopkim0 jinseopkim0 Apr 24, 2026

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Is this relevant? If INIT_CHANNEL_COUNT = 5 and CHANNEL_POOL_MAX_RPCS_PER_CHANNEL = 50, the max QPS would be 250, right?

@lqiu96 lqiu96 Apr 24, 2026 •
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500 streams is the theoretical max as GFE will enforce a limit of 100 streams/ channel. However CHANNEL_POOL_MAX_RPCS_PER_CHANNEL refers to the channel pool config where we aim to have an avg of 50 streams/ channel

// rely on the ChannelPool to resize according to the client's average load.
public static final int INIT_CHANNEL_COUNT = 5;
// Default to be larger than Gax's default (2) to better scale with spikes in requests
static final int CHANNEL_POOL_DEFAULT_RESIZE_DELTA = 5;
// Configure this default to be 100 to match the typical default `MAX_CONCURRENT_STREAMS`.
// Larger values *may* experience possible client-side queueing as excess streams cannot be
// multiplexed onto a full Http2 connection.
static final int CHANNEL_POOL_MAX_RPCS_PER_CHANNEL = 100;

// Configure the min and max RPC/Channel default in accordance to Datastore configuration guide:
// https://docs.cloud.google.com/datastore/docs/java-client-grpc#connection_pool_configuration
static final int CHANNEL_POOL_MIN_RPCS_PER_CHANNEL = 10;
static final int CHANNEL_POOL_MAX_RPCS_PER_CHANNEL = 50;

public static final int MIN_CHANNEL_COUNT = 1;

// This is a default max channel constant value set to handle the default initial channel
Expand Down Expand Up @@ -246,11 +253,13 @@ private DatastoreOptions(Builder builder) {
// Datastore sets the initial channel pool count to be 5 channels to allow better handle
// large loads of requests and the resize delta to be 5 to scale quicker. In cases of low
// load, the channel count will scale down as needed and memory will be freed. The default
// configuration is set to try and handle ~500 QPS and will scale up and down as needed.
// configuration is set to try and handle an average of ~250 QPS and will scale up and down
// as needed.
ChannelPoolSettings datastoreChannelPoolSettings =
ChannelPoolSettings.builder()
.setInitialChannelCount(INIT_CHANNEL_COUNT)
.setMinChannelCount(MIN_CHANNEL_COUNT)
.setMinRpcsPerChannel(CHANNEL_POOL_MIN_RPCS_PER_CHANNEL)
.setMaxRpcsPerChannel(CHANNEL_POOL_MAX_RPCS_PER_CHANNEL)
.setMaxResizeDelta(CHANNEL_POOL_DEFAULT_RESIZE_DELTA)
.build();
Expand Down
13 changes: 8 additions & 5 deletions ...google-cloud-datastore/src/test/java/com/google/cloud/datastore/DatastoreOptionsTest.java
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Expand Up @@ -184,12 +184,15 @@ public void testGrpcDefaultChannelConfigurations() {
ChannelPoolSettings channelPoolSettings =
((InstantiatingGrpcChannelProvider) datastoreOptions.getTransportChannelProvider())
.getChannelPoolSettings();
assertEquals(channelPoolSettings.getInitialChannelCount(), DatastoreOptions.INIT_CHANNEL_COUNT);
assertEquals(channelPoolSettings.getMinChannelCount(), DatastoreOptions.MIN_CHANNEL_COUNT);
assertEquals(channelPoolSettings.getMaxChannelCount(), DEFAULT_MAX_CHANNEL_COUNT);
assertEquals(DatastoreOptions.INIT_CHANNEL_COUNT, channelPoolSettings.getInitialChannelCount());
assertEquals(DatastoreOptions.MIN_CHANNEL_COUNT, channelPoolSettings.getMinChannelCount());
assertEquals(DEFAULT_MAX_CHANNEL_COUNT, channelPoolSettings.getMaxChannelCount());
assertEquals(
channelPoolSettings.getMaxRpcsPerChannel(),
DatastoreOptions.CHANNEL_POOL_MAX_RPCS_PER_CHANNEL);
DatastoreOptions.CHANNEL_POOL_MIN_RPCS_PER_CHANNEL,
channelPoolSettings.getMinRpcsPerChannel());
assertEquals(
DatastoreOptions.CHANNEL_POOL_MAX_RPCS_PER_CHANNEL,
channelPoolSettings.getMaxRpcsPerChannel());
}

@Test
Expand Down
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