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feat: replace ahash with murmur3 on generating tsid #3007

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merged 2 commits into from
Dec 26, 2023
Merged

feat: replace ahash with murmur3 on generating tsid #3007

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23f6310
feat: replace ahash with murmur3 on generating tsid
waynexia Dec 26, 2023
3c695b0
change random seed
waynexia Dec 26, 2023
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8 changes: 7 additions & 1 deletion Cargo.lock
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2 changes: 1 addition & 1 deletion src/metric-engine/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ edition.workspace = true
license.workspace = true

[dependencies]
ahash.workspace = true
api.workspace = true
aquamarine.workspace = true
async-trait.workspace = true
Expand All @@ -20,6 +19,7 @@ datafusion.workspace = true
datatypes.workspace = true
lazy_static = "1.4"
mito2.workspace = true
mur3 = "0.1"
object-store.workspace = true
prometheus.workspace = true
serde_json.workspace = true
Expand Down
3 changes: 0 additions & 3 deletions src/metric-engine/src/engine.rs
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Expand Up @@ -40,9 +40,6 @@ use self::state::MetricEngineState;
use crate::data_region::DataRegion;
use crate::metadata_region::MetadataRegion;

/// Fixed random state for generating tsid
pub(crate) const RANDOM_STATE: ahash::RandomState = ahash::RandomState::with_seeds(1, 2, 3, 4);

#[cfg_attr(doc, aquamarine::aquamarine)]
/// # Metric Engine
///
Expand Down
33 changes: 17 additions & 16 deletions src/metric-engine/src/engine/put.rs
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Expand Up @@ -14,7 +14,6 @@

use std::hash::{BuildHasher, Hash, Hasher};

use ahash::RandomState;
use api::v1::value::ValueData;
use api::v1::{ColumnDataType, ColumnSchema, Row, Rows, SemanticType};
use common_telemetry::{error, info};
Expand All @@ -25,13 +24,16 @@ use store_api::metric_engine_consts::{
use store_api::region_request::{AffectedRows, RegionPutRequest};
use store_api::storage::{RegionId, TableId};

use crate::engine::{MetricEngineInner, RANDOM_STATE};
use crate::engine::MetricEngineInner;
use crate::error::{
ColumnNotFoundSnafu, ForbiddenPhysicalAlterSnafu, LogicalRegionNotFoundSnafu, Result,
};
use crate::metrics::FORBIDDEN_OPERATION_COUNT;
use crate::utils::{to_data_region_id, to_metadata_region_id};

// A random number
const TSID_HASH_SEED: u32 = 846793005;

impl MetricEngineInner {
/// Dispatch region put request
pub async fn put_region(
Expand Down Expand Up @@ -174,22 +176,20 @@ impl MetricEngineInner {
});

// fill internal columns
let mut random_state = RANDOM_STATE.clone();
for row in &mut rows.rows {
Self::fill_internal_columns(&mut random_state, table_id, &tag_col_indices, row);
Self::fill_internal_columns(table_id, &tag_col_indices, row);
}

Ok(())
}

/// Fills internal columns of a row with table name and a hash of tag values.
fn fill_internal_columns(
random_state: &mut RandomState,
table_id: TableId,
tag_col_indices: &[(usize, String)],
row: &mut Row,
) {
let mut hasher = random_state.build_hasher();
let mut hasher = mur3::Hasher128::with_seed(TSID_HASH_SEED);
for (idx, name) in tag_col_indices {
let tag = row.values[*idx].clone();
name.hash(&mut hasher);
Expand All @@ -198,7 +198,8 @@ impl MetricEngineInner {
string.hash(&mut hasher);
}
}
let hash = hasher.finish();
// TSID is 64 bits, simply truncate the 128 bits hash
let (hash, _) = hasher.finish128();

// fill table id and tsid
row.values.push(ValueData::U32Value(table_id).into());
Expand Down Expand Up @@ -247,15 +248,15 @@ mod tests {
.unwrap();
let batches = RecordBatches::try_collect(stream).await.unwrap();
let expected = "\
+-------------------------+----------------+------------+---------------------+-------+
| greptime_timestamp | greptime_value | __table_id | __tsid | job |
+-------------------------+----------------+------------+---------------------+-------+
| 1970-01-01T00:00:00 | 0.0 | 3 | 4844750677434873907 | tag_0 |
| 1970-01-01T00:00:00.001 | 1.0 | 3 | 4844750677434873907 | tag_0 |
| 1970-01-01T00:00:00.002 | 2.0 | 3 | 4844750677434873907 | tag_0 |
| 1970-01-01T00:00:00.003 | 3.0 | 3 | 4844750677434873907 | tag_0 |
| 1970-01-01T00:00:00.004 | 4.0 | 3 | 4844750677434873907 | tag_0 |
+-------------------------+----------------+------------+---------------------+-------+";
+-------------------------+----------------+------------+----------------------+-------+
| greptime_timestamp | greptime_value | __table_id | __tsid | job |
+-------------------------+----------------+------------+----------------------+-------+
| 1970-01-01T00:00:00 | 0.0 | 3 | 12881218023286672757 | tag_0 |
| 1970-01-01T00:00:00.001 | 1.0 | 3 | 12881218023286672757 | tag_0 |
| 1970-01-01T00:00:00.002 | 2.0 | 3 | 12881218023286672757 | tag_0 |
| 1970-01-01T00:00:00.003 | 3.0 | 3 | 12881218023286672757 | tag_0 |
| 1970-01-01T00:00:00.004 | 4.0 | 3 | 12881218023286672757 | tag_0 |
+-------------------------+----------------+------------+----------------------+-------+";
assert_eq!(expected, batches.pretty_print().unwrap(), "physical region");

// read data from logical region
Expand Down
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