DBZ-496 The call to MemoryContextReset frees all allocated memory, which is both more

efficient and more reliable than individually freeing each allocated object.

Author: DuncanSands

src/decoderbufs.c

@@ -195,76 +195,6 @@ static void pg_decode_commit_txn(LogicalDecodingContext *ctx,
                                  ReorderBufferTXN *txn, XLogRecPtr commit_lsn) {
 }
 
-/* convenience method to free up sub-messages */
-static void row_message_destroy(Decoderbufs__RowMessage *msg) {
-  if (!msg) {
-    return;
-  }
-
-  if (msg->table) {
-    pfree(msg->table);
-  }
-
-  if (msg->n_new_tuple > 0) {
-    for (int i = 0; i < msg->n_new_tuple; i++) {
-      if (msg->new_tuple[i]) {
-        switch (msg->new_tuple[i]->datum_case) {
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_STRING:
-            if (msg->new_tuple[i]->datum_string) {
-              pfree(msg->new_tuple[i]->datum_string);
-            }
-            break;
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_BYTES:
-            if (msg->new_tuple[i]->datum_bytes.data) {
-              pfree(msg->new_tuple[i]->datum_bytes.data);
-              msg->new_tuple[i]->datum_bytes.data = NULL;
-              msg->new_tuple[i]->datum_bytes.len = 0;
-            }
-            break;
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT:
-            if (msg->new_tuple[i]->datum_point) {
-              pfree(msg->new_tuple[i]->datum_point);
-            }
-            break;
-          default:
-            break;
-        }
-        pfree(msg->new_tuple[i]);
-      }
-    }
-    pfree(msg->new_tuple);
-  }
-  if (msg->n_old_tuple > 0) {
-    for (int i = 0; i < msg->n_old_tuple; i++) {
-      if (msg->old_tuple[i]) {
-        switch (msg->old_tuple[i]->datum_case) {
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_STRING:
-            if (msg->old_tuple[i]->datum_string) {
-              pfree(msg->old_tuple[i]->datum_string);
-            }
-            break;
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_BYTES:
-            if (msg->old_tuple[i]->datum_bytes.data) {
-              pfree(msg->old_tuple[i]->datum_bytes.data);
-              msg->old_tuple[i]->datum_bytes.data = NULL;
-              msg->old_tuple[i]->datum_bytes.len = 0;
-            }
-            break;
-          case DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT:
-            if (msg->old_tuple[i]->datum_point) {
-              pfree(msg->old_tuple[i]->datum_point);
-            }
-            break;
-          default:
-            break;
-        }
-        pfree(msg->old_tuple[i]);
-      }
-    }
-    pfree(msg->old_tuple);
-  }
-}
-
 /* print tuple datums (only used for debug-mode) */
 static void print_tuple_datums(StringInfo out, Decoderbufs__DatumMessage **tup,
                                size_t n) {
@@ -363,8 +293,6 @@ static double numeric_to_double_no_overflow(Numeric num) {
                     tmp)));
   }
 
-  pfree(tmp);
-
   return val;
 }
 
@@ -676,17 +604,16 @@ static void pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
   TupleDesc tupdesc;
   Decoderbufs__RowMessage rmsg = DECODERBUFS__ROW_MESSAGE__INIT;
 
-  elog(DEBUG1, "Entering decode_change  callback");
+  elog(DEBUG1, "Entering decode_change callback");
+
+  /* Avoid leaking memory by using and resetting our own context */
+  data = ctx->output_plugin_private;
+  old = MemoryContextSwitchTo(data->context);
 
   replident = relation->rd_rel->relreplident;
 
   class_form = RelationGetForm(relation);
 
-  data = ctx->output_plugin_private;
-
-  /* Avoid leaking memory by using and resetting our own context */
-  old = MemoryContextSwitchTo(data->context);
-
   RelationGetIndexList(relation);
   is_rel_non_selective = (replident == REPLICA_IDENTITY_NOTHING ||
                           (replident == REPLICA_IDENTITY_DEFAULT &&
@@ -790,14 +717,10 @@ static void pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
     void *packed = palloc(psize);
     size_t ssize = decoderbufs__row_message__pack(&rmsg, packed);
     appendBinaryStringInfo(ctx->out, packed, ssize);
-    /* free packed buffer */
-    pfree(packed);
   }
   OutputPluginWrite(ctx, true);
 
-  /* cleanup msg */
-  row_message_destroy(&rmsg);
-
+  /* Cleanup, freeing memory */
   MemoryContextSwitchTo(old);
   MemoryContextReset(data->context);
 }