Rename LVRelState->frozen_pages

Rename frozen_pages to new_frozen_tuple_pages in LVRelState, the struct
used for tracking state during vacuuming of a heap relation.
frozen_pages sounds like it tracks pages set all-frozen. That is a
misnomer. It only includes pages with at least one newly frozen tuple.
It also includes pages that are not all-frozen.

Author: Melanie Plageman
Reviewed-by: Andres Freund, Masahiko Sawada, Nitin Jadhav, Bilal Yavuz
Discussion: https://postgr.es/m/ctdjzroezaxmiyah3gwbwm67defsrwj2b5fpfs4ku6msfpxeia%40mwjyqlhwr2wu

diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 6a3588cf817f0a3d1515178b1a542ba5e0115b1c..3077ee8ec32db686a8b5d73b34e3d267a30c047a 100644 (file)
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -188,7 +188,7 @@ typedef struct LVRelState
    BlockNumber rel_pages;      /* total number of pages */
    BlockNumber scanned_pages;  /* # pages examined (not skipped via VM) */
    BlockNumber removed_pages;  /* # pages removed by relation truncation */
-   BlockNumber frozen_pages;   /* # pages with newly frozen tuples */
+   BlockNumber new_frozen_tuple_pages; /* # pages with newly frozen tuples */
    BlockNumber lpdead_item_pages;  /* # pages with LP_DEAD items */
    BlockNumber missed_dead_pages;  /* # pages with missed dead tuples */
    BlockNumber nonempty_pages; /* actually, last nonempty page + 1 */
@@ -407,7 +407,7 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
    /* Initialize page counters explicitly (be tidy) */
    vacrel->scanned_pages = 0;
    vacrel->removed_pages = 0;
-   vacrel->frozen_pages = 0;
+   vacrel->new_frozen_tuple_pages = 0;
    vacrel->lpdead_item_pages = 0;
    vacrel->missed_dead_pages = 0;
    vacrel->nonempty_pages = 0;
@@ -696,9 +696,10 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
                                 vacrel->NewRelminMxid, diff);
            }
            appendStringInfo(&buf, _("frozen: %u pages from table (%.2f%% of total) had %lld tuples frozen\n"),
-                            vacrel->frozen_pages,
+                            vacrel->new_frozen_tuple_pages,
                             orig_rel_pages == 0 ? 100.0 :
-                            100.0 * vacrel->frozen_pages / orig_rel_pages,
+                            100.0 * vacrel->new_frozen_tuple_pages /
+                            orig_rel_pages,
                             (long long) vacrel->tuples_frozen);
            if (vacrel->do_index_vacuuming)
            {
@@ -1453,11 +1454,12 @@ lazy_scan_prune(LVRelState *vacrel,
    if (presult.nfrozen > 0)
    {
        /*
-        * We don't increment the frozen_pages instrumentation counter when
-        * nfrozen == 0, since it only counts pages with newly frozen tuples
-        * (don't confuse that with pages newly set all-frozen in VM).
+        * We don't increment the new_frozen_tuple_pages instrumentation
+        * counter when nfrozen == 0, since it only counts pages with newly
+        * frozen tuples (don't confuse that with pages newly set all-frozen
+        * in VM).
         */
-       vacrel->frozen_pages++;
+       vacrel->new_frozen_tuple_pages++;
    }
 
    /*