Struct ChangeEvent 

pub struct ChangeEvent {
    pub event_type: EventType,
    pub lsn: Lsn,
    pub metadata: Option<HashMap<String, Value>>,
}

Represents a single change event from PostgreSQL logical replication

Fields

event_type: EventType

Type of the event with embedded data

lsn: Lsn

LSN (Log Sequence Number) position

metadata: Option<HashMap<String, Value>>

Additional metadata

Implementations

impl ChangeEvent

pub fn insert( schema_name: String, table_name: String, relation_oid: u32, data: HashMap<String, Value>, lsn: Lsn, ) -> ChangeEvent

Create a new INSERT event

Arguments

• schema_name - Database schema name
• table_name - Table name
• relation_oid - PostgreSQL relation OID
• data - Inserted row data as column_name -> value map
• lsn - Log Sequence Number for this event

Example

use pg_walstream::{ChangeEvent, Lsn};
use std::collections::HashMap;

let mut data = HashMap::new();
data.insert("id".to_string(), serde_json::json!(1));
data.insert("name".to_string(), serde_json::json!("Alice"));

let event = ChangeEvent::insert(
    "public".to_string(),
    "users".to_string(),
    12345,
    data,
    Lsn::new(0x16B374D848),
);

pub fn update( schema_name: String, table_name: String, relation_oid: u32, old_data: Option<HashMap<String, Value>>, new_data: HashMap<String, Value>, replica_identity: ReplicaIdentity, key_columns: Vec<String>, lsn: Lsn, ) -> ChangeEvent

Create a new UPDATE event

Arguments

• schema_name - Database schema name
• table_name - Table name
• relation_oid - PostgreSQL relation OID
• old_data - Previous row data (may be None depending on replica identity)
• new_data - New row data after update
• replica_identity - Table’s replica identity setting (affects old_data availability)
• key_columns - Names of columns that form the replica identity key
• lsn - Log Sequence Number for this event

Example

use pg_walstream::{ChangeEvent, ReplicaIdentity, Lsn};
use std::collections::HashMap;

let mut old_data = HashMap::new();
old_data.insert("id".to_string(), serde_json::json!(1));
old_data.insert("name".to_string(), serde_json::json!("Alice"));

let mut new_data = HashMap::new();
new_data.insert("id".to_string(), serde_json::json!(1));
new_data.insert("name".to_string(), serde_json::json!("Bob"));

let event = ChangeEvent::update(
    "public".to_string(),
    "users".to_string(),
    12345,
    Some(old_data),
    new_data,
    ReplicaIdentity::Default,
    vec!["id".to_string()],
    Lsn::new(0x16B374D848),
);

pub fn delete( schema_name: String, table_name: String, relation_oid: u32, old_data: HashMap<String, Value>, replica_identity: ReplicaIdentity, key_columns: Vec<String>, lsn: Lsn, ) -> ChangeEvent

Create a new DELETE event

Arguments

• schema_name - Database schema name
• table_name - Table name
• relation_oid - PostgreSQL relation OID
• old_data - Deleted row data (columns available depend on replica identity)
• replica_identity - Table’s replica identity setting
• key_columns - Names of columns that form the replica identity key
• lsn - Log Sequence Number for this event

Example

use pg_walstream::{ChangeEvent, ReplicaIdentity, Lsn};
use std::collections::HashMap;

let mut old_data = HashMap::new();
old_data.insert("id".to_string(), serde_json::json!(1));
old_data.insert("name".to_string(), serde_json::json!("Alice"));

let event = ChangeEvent::delete(
    "public".to_string(),
    "users".to_string(),
    12345,
    old_data,
    ReplicaIdentity::Full,
    vec!["id".to_string()],
    Lsn::new(0x16B374D848),
);

pub fn begin( transaction_id: u32, final_lsn: Lsn, commit_timestamp: DateTime<Utc>, lsn: Lsn, ) -> ChangeEvent

Create a BEGIN transaction event

Marks the beginning of a transaction in the replication stream.

Arguments

• transaction_id - PostgreSQL transaction ID (XID)
• final_lsn - The final LSN of the transaction
• commit_timestamp - Transaction start timestamp
• lsn - Log Sequence Number for this event

pub fn commit( commit_timestamp: DateTime<Utc>, lsn: Lsn, commit_lsn: Lsn, end_lsn: Lsn, ) -> ChangeEvent

Create a COMMIT transaction event

Marks the successful commit of a transaction in the replication stream.

Arguments

• commit_timestamp - Transaction commit timestamp
• lsn - Log Sequence Number for this event

pub fn truncate(tables: Vec<String>, lsn: Lsn) -> ChangeEvent

Create a TRUNCATE event

Arguments

• tables - List of table names that were truncated
• lsn - Log Sequence Number for this event

pub fn relation(lsn: Lsn) -> ChangeEvent

Create a RELATION event

Arguments

• lsn - Log Sequence Number for this event

pub fn type_event(lsn: Lsn) -> ChangeEvent

Create a TYPE event

Arguments

• lsn - Log Sequence Number for this event

pub fn origin(lsn: Lsn) -> ChangeEvent

Create an ORIGIN event

Arguments

• lsn - Log Sequence Number for this event

pub fn message(lsn: Lsn) -> ChangeEvent

Create a MESSAGE event

Arguments

• lsn - Log Sequence Number for this event

pub fn with_metadata(self, metadata: HashMap<String, Value>) -> ChangeEvent

Set metadata for this event

pub fn get_key_columns(&self) -> Option<&Vec<String>>

Get key columns from UPDATE or DELETE events

pub fn get_replica_identity(&self) -> Option<&ReplicaIdentity>

Get replica identity from UPDATE or DELETE events

pub fn event_type_str(&self) -> &str

Trait Implementations

impl Clone for ChangeEvent

fn clone(&self) -> ChangeEvent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChangeEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ChangeEvent

fn deserialize<__D>( __deserializer: __D, ) -> Result<ChangeEvent, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ChangeEvent

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.