pg_prewarm: Allow autoprewarm to use more than 1GB to dump blocks.

Reported-by: Daria Shanina <vilensipkdm@gmail.com>
Author: Daria Shanina <vilensipkdm@gmail.com>
Author: Robert Haas <robertmhaas@gmail.com>
Backpatch-through: 13

diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
index c0c4f5d9ca7c9ee04ca5c19a095a6706ef0b441c..c308286f94d14c04ace359f918aaf684f705193d 100644 (file)
--- a/contrib/pg_prewarm/autoprewarm.c
+++ b/contrib/pg_prewarm/autoprewarm.c
@@ -609,8 +609,15 @@ apw_dump_now(bool is_bgworker, bool dump_unlogged)
        return 0;
    }
 
-   block_info_array =
-       (BlockInfoRecord *) palloc(sizeof(BlockInfoRecord) * NBuffers);
+   /*
+    * With sufficiently large shared_buffers, allocation will exceed 1GB, so
+    * allow for a huge allocation to prevent outright failure.
+    *
+    * (In the future, it might be a good idea to redesign this to use a more
+    * memory-efficient data structure.)
+    */
+   block_info_array = (BlockInfoRecord *)
+       palloc_extended((sizeof(BlockInfoRecord) * NBuffers), MCXT_ALLOC_HUGE);
 
    for (num_blocks = 0, i = 0; i < NBuffers; i++)
    {