Remove unneeded old_rel_pages VACUUM state field.

The field hasn't been used since commit 3d351d91, which redefined
pg_class.reltuples to be -1 before the first VACUUM or ANALYZE.

Also rename a local variable of the same name ("old_rel_pages"). This is
used by relation truncation to represent the original relation size at
the start of the ongoing VACUUM operation.  Rename it to orig_rel_pages,
since that's a lot clearer.  (This name matches similar nearby code.)

diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 2589f80a52fa4424692c67f08765de404cb5212c..19d8276de2c8bf59ef172c392bbcc7031e102da7 100644 (file)
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -323,12 +323,10 @@ typedef struct LVRelState
    BufferAccessStrategy bstrategy;
    LVParallelState *lps;
 
-   /* Statistics from pg_class when we start out */
-   BlockNumber old_rel_pages;  /* previous value of pg_class.relpages */
-   double      old_live_tuples;    /* previous value of pg_class.reltuples */
    /* rel's initial relfrozenxid and relminmxid */
    TransactionId relfrozenxid;
    MultiXactId relminmxid;
+   double      old_live_tuples;    /* previous value of pg_class.reltuples */
 
    /* VACUUM operation's cutoff for pruning */
    TransactionId OldestXmin;
@@ -593,10 +591,9 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
    }
 
    vacrel->bstrategy = bstrategy;
-   vacrel->old_rel_pages = rel->rd_rel->relpages;
-   vacrel->old_live_tuples = rel->rd_rel->reltuples;
    vacrel->relfrozenxid = rel->rd_rel->relfrozenxid;
    vacrel->relminmxid = rel->rd_rel->relminmxid;
+   vacrel->old_live_tuples = rel->rd_rel->reltuples;
 
    /* Set cutoffs for entire VACUUM */
    vacrel->OldestXmin = OldestXmin;
@@ -3182,7 +3179,7 @@ should_attempt_truncation(LVRelState *vacrel)
 static void
 lazy_truncate_heap(LVRelState *vacrel)
 {
-   BlockNumber old_rel_pages = vacrel->rel_pages;
+   BlockNumber orig_rel_pages = vacrel->rel_pages;
    BlockNumber new_rel_pages;
    bool        lock_waiter_detected;
    int         lock_retry;
@@ -3246,7 +3243,7 @@ lazy_truncate_heap(LVRelState *vacrel)
         * the newly added pages presumably contain non-deletable tuples.
         */
        new_rel_pages = RelationGetNumberOfBlocks(vacrel->rel);
-       if (new_rel_pages != old_rel_pages)
+       if (new_rel_pages != orig_rel_pages)
        {
            /*
             * Note: we intentionally don't update vacrel->rel_pages with the
@@ -3268,7 +3265,7 @@ lazy_truncate_heap(LVRelState *vacrel)
        new_rel_pages = count_nondeletable_pages(vacrel, &lock_waiter_detected);
        vacrel->blkno = new_rel_pages;
 
-       if (new_rel_pages >= old_rel_pages)
+       if (new_rel_pages >= orig_rel_pages)
        {
            /* can't do anything after all */
            UnlockRelation(vacrel->rel, AccessExclusiveLock);
@@ -3294,16 +3291,16 @@ lazy_truncate_heap(LVRelState *vacrel)
         * without also touching reltuples, since the tuple count wasn't
         * changed by the truncation.
         */
-       vacrel->pages_removed += old_rel_pages - new_rel_pages;
+       vacrel->pages_removed += orig_rel_pages - new_rel_pages;
        vacrel->rel_pages = new_rel_pages;
 
        ereport(elevel,
                (errmsg("\"%s\": truncated %u to %u pages",
                        vacrel->relname,
-                       old_rel_pages, new_rel_pages),
+                       orig_rel_pages, new_rel_pages),
                 errdetail_internal("%s",
                                    pg_rusage_show(&ru0))));
-       old_rel_pages = new_rel_pages;
+       orig_rel_pages = new_rel_pages;
    } while (new_rel_pages > vacrel->nonempty_pages && lock_waiter_detected);
 }