IGNITE-28651 Document Calcite SQL memory quotas in Ignite 2.x documentation

docs/Gemfile

@@ -4,7 +4,7 @@ source "https://rubygems.org"
 
 gem 'asciidoctor'
 gem 'jekyll', group: :jekyll_plugins
-gem 'wdm', '~> 0.1.1' if Gem.win_platform?
+# gem 'wdm', '~> 0.1.1' if Gem.win_platform?
 group :jekyll_plugins do
   gem 'jekyll-asciidoc'
   gem 'jekyll-sass-converter', '~> 2.2'
@@ -13,6 +13,10 @@ end
 gem 'thread_safe', '~> 0.3.6'
 gem 'slim', '~> 4.0.1'
 gem 'tilt', '~> 2.0.9'
+gem 'bigdecimal', '~> 4.1'
+gem 'base64', '~> 0.3'
+gem 'csv', '~> 3.3'
+gem 'logger', '~> 1.7'
 
 # Ruby 3.0.0 requires dependency which doesn't contains in the bundle
 gem "webrick", "~> 1.7"

docs/_docs/SQL/sql-calcite.adoc

@@ -121,6 +121,62 @@ QUERY_ENGINE=CALCITE
 ----
 --
 
+== Memory Quotas [[memory-quotas]]
+
+The Calcite-based SQL engine can track and limit heap memory accounted by Calcite query execution operators.
+This is useful for protecting a server node from a single large query or from many concurrent memory-heavy queries.
+
+Two types of quotas can be configured in `CalciteQueryEngineConfiguration`:
+
+* `globalMemoryQuota` - a per-node heap memory quota for all Calcite SQL queries running on the node.
+* `queryMemoryQuota` - a per-node heap memory quota for each Calcite SQL query running on the node.
+
+Both quotas are disabled by default (`0`).
+The quota values are specified in bytes.
+If a quota is exceeded, the query fails with an exception.
+The global quota error message contains `Global memory quota for SQL queries exceeded`, and the per-query quota error message contains `Query quota exceeded`.
+
+The quota is applied to query execution structures that keep rows in heap memory, for example sorting, hash joins, hash aggregates, set operations, collection operations, spools, and result materialization.
+It is not a process memory limit and it does not account for Ignite data regions, direct memory, JVM native memory, or the operating system page cache.
+The quotas are per-node.
+For a distributed query, total memory consumption across the cluster can be higher because the limit is applied independently on every participating node.
+Size these quotas together with `-Xmx` and the expected SQL concurrency.
+
+[tabs]
+--
+tab:XML[]
+[source,xml]
+----
+<bean class="org.apache.ignite.configuration.IgniteConfiguration">
+    <property name="sqlConfiguration">
+        <bean class="org.apache.ignite.configuration.SqlConfiguration">
+            <property name="queryEnginesConfiguration">
+                <list>
+                    <bean class="org.apache.ignite.calcite.CalciteQueryEngineConfiguration">
+                        <property name="default" value="true"/>
+                        <property name="globalMemoryQuota" value="#{4L * 1024 * 1024 * 1024}"/>
+                        <property name="queryMemoryQuota" value="#{512L * 1024 * 1024}"/>
+                    </bean>
+                </list>
+            </property>
+        </bean>
+    </property>
+</bean>
+----
+tab:Java[]
+[source,java]
+----
+IgniteConfiguration cfg = new IgniteConfiguration().setSqlConfiguration(
+    new SqlConfiguration().setQueryEnginesConfiguration(
+        new CalciteQueryEngineConfiguration()
+            .setDefault(true)
+            .setGlobalMemoryQuota(4L * 1024 * 1024 * 1024)
+            .setQueryMemoryQuota(512L * 1024 * 1024)
+    )
+);
+----
+--
+
 == SQL Reference
 
 === DDL