On 1/3/19, Amit Kapila <amit.kapil...@gmail.com> wrote:
> Yeah, that makes sense, John, can you provide a patch on top of the
> current patch where we check either the last block or every other
> block.
I've attached two patches for testing. Each one applies on top of the
current patch.
Mithun, I'll respond to your other review comments later this week.
-John Naylor
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 2ab1cb58b7..d6352aabd9 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -1103,15 +1103,9 @@ fsm_allow_writes(Relation rel, BlockNumber heapblk,
static void
fsm_local_set(Relation rel, BlockNumber curr_nblocks)
{
- BlockNumber blkno,
- cached_target_block;
+ BlockNumber cached_target_block;
- /*
- * Mark blocks available starting after the last block we have mapped,
- * and ending at the current last block in the relation.
- */
- for (blkno = fsm_local_map.nblocks; blkno < curr_nblocks; blkno++)
- fsm_local_map.map[blkno] = FSM_LOCAL_AVAIL;
+ fsm_local_map.map[curr_nblocks - 1] = FSM_LOCAL_AVAIL;
/* Cache the number of blocks. */
fsm_local_map.nblocks = curr_nblocks;
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 2ab1cb58b7..820a2579ae 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -1110,8 +1110,15 @@ fsm_local_set(Relation rel, BlockNumber curr_nblocks)
* Mark blocks available starting after the last block we have mapped,
* and ending at the current last block in the relation.
*/
- for (blkno = fsm_local_map.nblocks; blkno < curr_nblocks; blkno++)
+ blkno = curr_nblocks - 1;
+ for (;;)
+ {
fsm_local_map.map[blkno] = FSM_LOCAL_AVAIL;
+ if (blkno >= fsm_local_map.nblocks + 2)
+ blkno -= 2;
+ else
+ break;
+ }
/* Cache the number of blocks. */
fsm_local_map.nblocks = curr_nblocks;
diff --git a/src/test/regress/expected/fsm.out b/src/test/regress/expected/fsm.out
index 4c44c4bd6e..973b9319e7 100644
--- a/src/test/regress/expected/fsm.out
+++ b/src/test/regress/expected/fsm.out
@@ -2,16 +2,16 @@
-- Free Space Map test
--
CREATE TABLE fsm_check_size (num int, str text);
--- Fill 2 blocks with as many large records as will fit
+-- Fill 3 blocks with as many large records as will fit
-- No FSM
INSERT INTO fsm_check_size SELECT g, rpad('', 1024, 'a')
-FROM generate_series(1,7*2) g;
+FROM generate_series(1,7*3) g;
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
heap_size | fsm_size
-----------+----------
- 16384 | 0
+ 24576 | 0
(1 row)
-- Clear some space on block 0
@@ -26,7 +26,7 @@ SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
heap_size | fsm_size
-----------+----------
- 16384 | 0
+ 24576 | 0
(1 row)
-- Extend table with enough blocks to exceed the FSM threshold
diff --git a/src/test/regress/sql/fsm.sql b/src/test/regress/sql/fsm.sql
index fad99da1c2..a864c7fd88 100644
--- a/src/test/regress/sql/fsm.sql
+++ b/src/test/regress/sql/fsm.sql
@@ -4,10 +4,10 @@
CREATE TABLE fsm_check_size (num int, str text);
--- Fill 2 blocks with as many large records as will fit
+-- Fill 3 blocks with as many large records as will fit
-- No FSM
INSERT INTO fsm_check_size SELECT g, rpad('', 1024, 'a')
-FROM generate_series(1,7*2) g;
+FROM generate_series(1,7*3) g;
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
@@ -16,7 +16,7 @@ pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
DELETE FROM fsm_check_size where num <= 5;
VACUUM fsm_check_size;
--- Insert small record in block 1 to set the cached smgr targetBlock
+-- Insert small record in block 2 to set the cached smgr targetBlock
INSERT INTO fsm_check_size values(99, 'b');
-- Insert large record and make sure it goes in block 0 rather than
