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());
 }
 
 /*