From 554106b1163853757b72ce14d7db5050c32bfa6a Mon Sep 17 00:00:00 2001
From: Robert Haas
Date: Mon, 8 Jul 2019 14:51:53 -0400
Subject: tableam: Provide helper functions for relation sizing.

Most block-based table AMs will need the exact same implementation of
the relation_size callback as the heap, and if they use a standard
page layout, they will likely need an implementation of the
relation_estimate_size callback that is very similar to that of the
heap.  Rearrange to facilitate code reuse.

Patch by me, reviewed by Michael Paquier, Daniel Gustafsson, and
Álvaro Herrera.

Discussion: http://postgr.es/m/CA+TgmoZ6DBPnP1E-vRpQZUJQijJFD54F+SR_pxGiAAS-MyrigA@mail.gmail.com
---
 src/include/access/tableam.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

(limited to 'src/include')

diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index fd07773b74f..7edfcf3ef9c 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -1727,6 +1727,20 @@ extern void table_block_parallelscan_startblock_init(Relation rel,
 													 ParallelBlockTableScanDesc pbscan);
 
 
+/* ----------------------------------------------------------------------------
+ * Helper functions to implement relation sizing for block oriented AMs.
+ * ----------------------------------------------------------------------------
+ */
+
+extern uint64 table_block_relation_size(Relation rel, ForkNumber forkNumber);
+extern void table_block_relation_estimate_size(Relation rel,
+											   int32 *attr_widths,
+											   BlockNumber *pages,
+											   double *tuples,
+											   double *allvisfrac,
+											   Size overhead_bytes_per_tuple,
+											   Size usable_bytes_per_page);
+
 /* ----------------------------------------------------------------------------
  * Functions in tableamapi.c
  * ----------------------------------------------------------------------------
-- 
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