#869 backport to Jaybird 5: #864 Increase default and maximum SQL info sizes

Author: mrotteveel

jaybird-native/src/main/java/org/firebirdsql/gds/ng/jna/JnaStatement.java

@@ -453,14 +453,13 @@ public byte[] getSqlInfo(byte[] requestItems, int bufferLength) throws SQLExcept
 
     @Override
     public int getDefaultSqlInfoSize() {
-        // TODO Test for an optimal buffer size
         return getMaxSqlInfoSize();
     }
 
     @Override
     public int getMaxSqlInfoSize() {
-        // TODO Is this the actual max, or is it 65535?
-        return 32767;
+        // Theoretically, also Firebird 2.1, but not supported since before Jaybird 5
+        return getDatabase().getServerVersion().isEqualOrAbove(2, 5) ? 65535 : 32767;
     }
 
     @Override

src/docs/asciidoc/release_notes.adoc

@@ -40,6 +40,20 @@ The following was fixed or changed since Jaybird 6.0.1:
 * Improvement: added `authPlugins` property on `FBManager` (https://github.com/FirebirdSQL/jaybird/issues/866[#866])
 +
 As part of this change, the interface `FBManagerMBean` now extends `AttachmentProperties`, so that all attachment properties are accessible.
+* Improvement: increased default and maximum SQL info sizes used for retrieving statement information like columns, parameters and plan information (https://github.com/FirebirdSQL/jaybird/issues/869[#869])
++
+The values were changed from the original default and maximum of 32,767 to:
++
+--
+* For pure Java connections:
+** protocol 12 (Firebird 2.5): 65,535 (default and maximum),
+** protocol 13 (Firebird 3.0) and higher: 512 KiB default, 16 MiB maximum. +
+* For native connections:
+** Firebird 2.5 and higher: 65,535 (default and maximum)
+--
++
+This change improves the performance of preparing statements with a lot of columns and parameters by reducing the number of round-trips needed to retrieve the column and parameter information.
+It may also prevent truncation of "`explained plans`" for statements with very complex or extensive plans.
 
 === Jaybird 6.0.1
 

src/main/org/firebirdsql/gds/ng/wire/version10/V10Statement.java

@@ -649,13 +649,11 @@ protected void processAllocateResponse(GenericResponse response) throws SQLExcep
 
     @Override
     public int getDefaultSqlInfoSize() {
-        // TODO Test for an optimal buffer size
         return getMaxSqlInfoSize();
     }
 
     @Override
     public int getMaxSqlInfoSize() {
-        // TODO Is this the actual max for the v10 protocol, or is it 65535?
         return 32767;
     }
 }

src/main/org/firebirdsql/gds/ng/wire/version12/V12Statement.java

@@ -36,4 +36,10 @@ public V12Statement(FbWireDatabase database) {
         super(database);
     }
 
+    @Override
+    public int getMaxSqlInfoSize() {
+        // Theoretically, also protocol 11 (Firebird 2.1), but not supported since before Jaybird 5
+        return 65535;
+    }
+
 }

src/main/org/firebirdsql/gds/ng/wire/version13/V13Statement.java

@@ -99,4 +99,17 @@ protected void writeSqlData(XdrOutputStream xdrOut, BlrCalculator blrCalculator,
             }
         }
     }
+
+    @Override
+    public int getDefaultSqlInfoSize() {
+        return 512 * 1024;
+    }
+
+    @Override
+    public int getMaxSqlInfoSize() {
+        // It can be higher: 0xFFFE_FFFF serverside, and Integer.MAX_VALUE - 8 due to Java array size limitations
+        // 16 MiB is probably already excessive
+        return 16 * 1024 * 1024;
+    }
+
 }