vacuumlazy.c: Further consolidate resource allocation.

Move remaining VACUUM resource allocation and deallocation code from
lazy_scan_heap() to its caller, heap_vacuum_rel().  This finishes off
work started by commit 73f6ec3d.

Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-Wzk3fNBa_S3Ngi+16GQiyJ=AmUu3oUY99syMDTMRxitfyQ@mail.gmail.com

diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 9b7114c1591e0166bf045e552b71112ff5f01c7f..9cdc8008c1e842698e44954e7d389ebe0b905592 100644 (file)
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -246,7 +246,7 @@ typedef struct LVSavedErrInfo
 
 
 /* non-export function prototypes */
-static void lazy_scan_heap(LVRelState *vacrel, int nworkers);
+static void lazy_scan_heap(LVRelState *vacrel);
 static BlockNumber lazy_scan_skip(LVRelState *vacrel, Buffer *vmbuffer,
                                                                  BlockNumber next_block,
                                                                  bool *next_unskippable_allvis,
@@ -514,11 +514,28 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
        vacrel->NewRelminMxid = OldestMxact;
        vacrel->skippedallvis = false;
 
+       /*
+        * Allocate dead_items array memory using dead_items_alloc.  This handles
+        * parallel VACUUM initialization as part of allocating shared memory
+        * space used for dead_items.  (But do a failsafe precheck first, to
+        * ensure that parallel VACUUM won't be attempted at all when relfrozenxid
+        * is already dangerously old.)
+        */
+       lazy_check_wraparound_failsafe(vacrel);
+       dead_items_alloc(vacrel, params->nworkers);
+
        /*
         * Call lazy_scan_heap to perform all required heap pruning, index
         * vacuuming, and heap vacuuming (plus related processing)
         */
-       lazy_scan_heap(vacrel, params->nworkers);
+       lazy_scan_heap(vacrel);
+
+       /*
+        * Free resources managed by dead_items_alloc.  This ends parallel mode in
+        * passing when necessary.
+        */
+       dead_items_cleanup(vacrel);
+       Assert(!IsInParallelMode());
 
        /*
         * Update pg_class entries for each of rel's indexes where appropriate.
@@ -825,14 +842,14 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
  *             supply.
  */
 static void
-lazy_scan_heap(LVRelState *vacrel, int nworkers)
+lazy_scan_heap(LVRelState *vacrel)
 {
-       VacDeadItems *dead_items;
        BlockNumber rel_pages = vacrel->rel_pages,
                                blkno,
                                next_unskippable_block,
-                               next_failsafe_block,
-                               next_fsm_block_to_vacuum;
+                               next_failsafe_block = 0,
+                               next_fsm_block_to_vacuum = 0;
+       VacDeadItems *dead_items = vacrel->dead_items;
        Buffer          vmbuffer = InvalidBuffer;
        bool            next_unskippable_allvis,
                                skipping_current_range;
@@ -843,23 +860,6 @@ lazy_scan_heap(LVRelState *vacrel, int nworkers)
        };
        int64           initprog_val[3];
 
-       /*
-        * Do failsafe precheck before calling dead_items_alloc.  This ensures
-        * that parallel VACUUM won't be attempted when relfrozenxid is already
-        * dangerously old.
-        */
-       lazy_check_wraparound_failsafe(vacrel);
-       next_failsafe_block = 0;
-
-       /*
-        * Allocate the space for dead_items.  Note that this handles parallel
-        * VACUUM initialization as part of allocating shared memory space used
-        * for dead_items.
-        */
-       dead_items_alloc(vacrel, nworkers);
-       dead_items = vacrel->dead_items;
-       next_fsm_block_to_vacuum = 0;
-
        /* Report that we're scanning the heap, advertising total # of blocks */
        initprog_val[0] = PROGRESS_VACUUM_PHASE_SCAN_HEAP;
        initprog_val[1] = rel_pages;
@@ -1236,12 +1236,13 @@ lazy_scan_heap(LVRelState *vacrel, int nworkers)
                }
        }
 
+       vacrel->blkno = InvalidBlockNumber;
+       if (BufferIsValid(vmbuffer))
+               ReleaseBuffer(vmbuffer);
+
        /* report that everything is now scanned */
        pgstat_progress_update_param(PROGRESS_VACUUM_HEAP_BLKS_SCANNED, blkno);
 
-       /* Clear the block number information */
-       vacrel->blkno = InvalidBlockNumber;
-
        /* now we can compute the new value for pg_class.reltuples */
        vacrel->new_live_tuples = vac_estimate_reltuples(vacrel->rel, rel_pages,
                                                                                                         vacrel->scanned_pages,
@@ -1256,15 +1257,9 @@ lazy_scan_heap(LVRelState *vacrel, int nworkers)
                vacrel->missed_dead_tuples;
 
        /*
-        * Release any remaining pin on visibility map page.
+        * Do index vacuuming (call each index's ambulkdelete routine), then do
+        * related heap vacuuming
         */
-       if (BufferIsValid(vmbuffer))
-       {
-               ReleaseBuffer(vmbuffer);
-               vmbuffer = InvalidBuffer;
-       }
-
-       /* Perform a final round of index and heap vacuuming */
        if (dead_items->num_items > 0)
                lazy_vacuum(vacrel);
 
@@ -1278,16 +1273,9 @@ lazy_scan_heap(LVRelState *vacrel, int nworkers)
        /* report all blocks vacuumed */
        pgstat_progress_update_param(PROGRESS_VACUUM_HEAP_BLKS_VACUUMED, blkno);
 
-       /* Do post-vacuum cleanup */
+       /* Do final index cleanup (call each index's amvacuumcleanup routine) */
        if (vacrel->nindexes > 0 && vacrel->do_index_cleanup)
                lazy_cleanup_all_indexes(vacrel);
-
-       /*
-        * Free resources managed by dead_items_alloc.  This ends parallel mode in
-        * passing when necessary.
-        */
-       dead_items_cleanup(vacrel);
-       Assert(!IsInParallelMode());
 }
 
 /*