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new 8d286cc799 IGNITE-17678 Added description for transaction changes.
Fixes #1079
8d286cc799 is described below
commit 8d286cc79924f5fc56bc47f60a77c28dbea636dc
Author: IgGusev <[email protected]>
AuthorDate: Tue Sep 20 13:53:06 2022 +0300
IGNITE-17678 Added description for transaction changes. Fixes #1079
Signed-off-by: Slava Koptilin <[email protected]>
---
.../transactions/performing-transactions.adoc | 70 +++++++++++++++++++++-
1 file changed, 68 insertions(+), 2 deletions(-)
diff --git a/docs/_docs/transactions/performing-transactions.adoc
b/docs/_docs/transactions/performing-transactions.adoc
index d3898239c9..a69986e2a5 100644
--- a/docs/_docs/transactions/performing-transactions.adoc
+++ b/docs/_docs/transactions/performing-transactions.adoc
@@ -16,9 +16,9 @@
This Alpha release introduces the key-value API that provides an interface for
starting and completing transactions.
-== Executing Transactions
+=== Synchronous Transactions
-Use the `igniteTransactions` class to create a transaction object and the
`commit` method to send it.
+Use the `igniteTransactions` class to create a transaction object, and the
`commit` method to send it.
[tabs]
--
@@ -30,6 +30,42 @@ tx.commit()
----
--
+You can also perform a rollback with the `rollback` command:
+
+[tabs]
+--
+tab:Java[]
+[source,java]
+----
+Transaction tx = igniteTransactions.begin();
+tx.rollback()
+----
+--
+
+
+Here is the example of a transaction that transfers money from one account to
another, and handles a possible overdraft:
+
+--
+[source,java]
+----
+Transaction tx = igniteTransactions.begin();
+
+try {
+ Tuple row1 = accounts.get(tx, Tuple.create().set("accountId", 1));
+ if (row1.doubleValue("balance") - amount < 0) {
+ tx.rollback();
+ return false;
+ }
+ Tuple row2 = accounts.get(tx, Tuple.create().set("accountId", 2);
+ accounts.upsert(tx, Tuple.create().set("accountId", 1).set("balance",
row1.doubleValue("balance") - amount));
+ accounts.upsert(tx, Tuple.create().set("accountId", 2).set("balance",
row2.doubleValue("balance") + amount));
+ tx.commit();
+} catch (Throwable t) {
+ tx.rollback();
+}
+----
+--
+
== Asynchronous Transactions
You can also perform transactions asynchronously.
@@ -57,4 +93,34 @@ igniteTransactions.beginAsync()
)
).thenCompose(Transaction::commitAsync).join();
----
+--
+
+
+== Implicit Transaction Management
+
+Apache Ignite 3 also provides implicit transaction managemet for dealing with
simpler transactions by using the `runInTransaction` class. When using it, the
following will be done automatically:
+
+- The transaction is started and substituted to the closure.
+- The transaction is committed if no exceptions were thrown during the closure.
+- The transaction will be retried in case of recoverable error. Closure must
be purely functional - not causing side effects.
+
+Here is the example of a transaction that transfers money from one account to
another, and handles a possible overdraft:
+
+[tabs]
+--
+tab:Java[]
+[source,java]
+----
+igniteTransactions.runInTransaction(tx -> {
+ CompletableFuture<Tuple> fut1 = view.getAsync(tx,
Tuple.create().set("accountId", 1));
+ CompletableFuture<Tuple> fut2 = view.getAsync(tx,
Tuple.create().set("accountId", 2)); // Read second balance concurrently
+ if (fut1.join().doubleValue("balance") - amount < 0) {
+ tx.rollback();
+ return;
+ }
+
+ view.upsertAsync(tx, Tuple.create().set("accountId", 1).set("balance",
fut1.join().doubleValue("balance") - amount));
+ view.upsertAsync(tx, Tuple.create().set("accountId", 2).set("balance",
fut2.join().doubleValue("balance") + amount);
+});
+----
--
\ No newline at end of file
