chore: drop revision from Durable State by slice index and migration docs (#561)

Author: sebastian-alfers

core/src/main/scala/akka/persistence/r2dbc/internal/h2/H2Dialect.scala

@@ -154,7 +154,7 @@ private[r2dbc] object H2Dialect extends Dialect {
       }
       val durableStateSliceIndexes = allDurableStateTablesWithSchema.map { table =>
         val sliceIndexWithSchema = table + "_slice_idx"
-        sql"""CREATE INDEX IF NOT EXISTS $sliceIndexWithSchema ON $table(slice, entity_type, db_timestamp, revision)"""
+        sql"""CREATE INDEX IF NOT EXISTS $sliceIndexWithSchema ON $table(slice, entity_type, db_timestamp)"""
       }
       journalSliceIndexes ++
       snapshotSliceIndexes ++
@@ -219,7 +219,7 @@ private[r2dbc] object H2Dialect extends Dialect {
           state_payload BYTEA NOT NULL,
           tags TEXT ARRAY,
 
-          PRIMARY KEY(persistence_id, revision)
+          PRIMARY KEY(persistence_id)
         )
       """
     }

ddl-scripts/create_tables_postgres.sql

@@ -61,4 +61,4 @@ CREATE TABLE IF NOT EXISTS durable_state (
 );
 
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
-CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp, revision);
+CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp);

ddl-scripts/create_tables_postgres_0-1.sql

@@ -121,5 +121,5 @@ CREATE TABLE IF NOT EXISTS durable_state_1 (
 );
 
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
-CREATE INDEX IF NOT EXISTS durable_state_0_slice_idx ON durable_state_0(slice, entity_type, db_timestamp, revision);
-CREATE INDEX IF NOT EXISTS durable_state_1_slice_idx ON durable_state_1(slice, entity_type, db_timestamp, revision);
+CREATE INDEX IF NOT EXISTS durable_state_0_slice_idx ON durable_state_0(slice, entity_type, db_timestamp);
+CREATE INDEX IF NOT EXISTS durable_state_1_slice_idx ON durable_state_1(slice, entity_type, db_timestamp);

ddl-scripts/create_tables_postgres_2-3.sql

@@ -121,5 +121,5 @@ CREATE TABLE IF NOT EXISTS durable_state_3 (
 );
 
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
-CREATE INDEX IF NOT EXISTS durable_state_2_slice_idx ON durable_state_2(slice, entity_type, db_timestamp, revision);
-CREATE INDEX IF NOT EXISTS durable_state_3_slice_idx ON durable_state_3(slice, entity_type, db_timestamp, revision);
+CREATE INDEX IF NOT EXISTS durable_state_2_slice_idx ON durable_state_2(slice, entity_type, db_timestamp);
+CREATE INDEX IF NOT EXISTS durable_state_3_slice_idx ON durable_state_3(slice, entity_type, db_timestamp);

ddl-scripts/create_tables_postgres_jsonb.sql

@@ -61,4 +61,4 @@ CREATE TABLE IF NOT EXISTS durable_state (
 );
 
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
-CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp, revision);
+CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp);

ddl-scripts/create_tables_sqlserver.sql

@@ -67,5 +67,5 @@ IF object_id('durable_state') is null
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
 IF NOT EXISTS(SELECT * FROM sys.indexes WHERE name = 'durable_state_slice_idx' AND object_id = OBJECT_ID('durable_state'))
     BEGIN
-        CREATE INDEX durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp, revision);
+        CREATE INDEX durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp);
     END;

ddl-scripts/create_tables_yugabyte.sql

@@ -63,5 +63,5 @@ CREATE TABLE IF NOT EXISTS durable_state (
 );
 
 -- `durable_state_slice_idx` is only needed if the slice based queries are used
-CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice ASC, entity_type ASC, db_timestamp ASC, revision ASC, persistence_id)
+CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice ASC, entity_type ASC, db_timestamp ASC, persistence_id)
   SPLIT AT VALUES ((127), (255), (383), (511), (639), (767), (895));

docs/src/main/paradox/migration-guide.md

@@ -14,6 +14,18 @@ DROP CONSTRAINT durable_state_pkey,
 ADD PRIMARY KEY(persistence_id);
 ```
 
+Same goes for the (optional) index `durable_state_slice_idx` used for slice base queries. To remove the column from the index, use:
+
+Postgres / Yugabyte:
+: ```sql
+DROP INDEX IF EXISTS durable_state_slice_idx;
+CREATE INDEX IF NOT EXISTS durable_state_slice_idx ON durable_state(slice, entity_type, db_timestamp);
+```
+
+As mentioned above, this is optional. Changes to the database schema like this one can have an impact on the availability of the database under certain conditions.
+
+Make sure to test them on a copy of your database to learn more about the potential impact.
+
 If you are using @ref[data partitioning](./data-partition.md), please make sure to apply the change to all tables.
 
 ## 1.1.x to 1.2.0