mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-21 08:29:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

Update lazy_scan_heap header comment.

Browse Source 
The previous comment described how things worked in PostgreSQL 8.2
and prior.
This commit is contained in:
Robert Haas 2012-04-13 08:49:59 -04:00
parent 81e3e4fd14
commit 5630eddf1e
1 changed files with 11 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/backend/commands/vacuumlazy.c
View File

@ -342,13 +342,18 @@ vacuum_log_cleanup_info(Relation rel, LVRelStats *vacrelstats)
/* /*
* lazy_scan_heap() -- scan an open heap relation * lazy_scan_heap() -- scan an open heap relation
* *
* This routine sets commit status bits, builds lists of dead tuples * This routine prunes each page in the heap, which will among other
* and pages with free space, and calculates statistics on the number * things truncate dead tuples to dead line pointers, defragment the
* of live tuples in the heap. When done, or when we run low on space * page, and set commit status bits (see heap_page_prune). It also builds
* for dead-tuple TIDs, invoke vacuuming of indexes and heap. * lists of dead tuples and pages with free space, calculates statistics
* on the number of live tuples in the heap, and marks pages as
* all-visible if appropriate. When done, or when we run low on space for
* dead-tuple TIDs, invoke vacuuming of indexes and call lazy_vacuum_heap
* to reclaim dead line pointers.
* *
* If there are no indexes then we just vacuum each dirty page as we * If there are no indexes then we can reclaim line pointers on the fly;
* process it, since there's no point in gathering many tuples. * dead line pointers need only be retained until all index pointers that
* reference them have been killed.
*/ */
static void static void
lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,