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++;
        }
 
        /*