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Streamline handling of the various strategies that we have to avoid a page split in nbtinsert.c. When it looks like a leaf page is about to overflow, we now perform deleting LP_DEAD items and deduplication in one central place. This greatly simplifies _bt_findinsertloc(). This has an independently useful consequence: nbtree no longer relies on the BTP_HAS_GARBAGE page level flag/hint for anything important. We still set and unset the flag in the same way as before, but it's no longer treated as a gating condition when considering if we should check for already-set LP_DEAD bits. This happens at the point where the page looks like it might have to be split anyway, so simply checking the LP_DEAD bits in passing is practically free. This avoids missing LP_DEAD bits just because the page-level hint is unset, which is probably reasonably common (e.g. it happens when VACUUM unsets the page-level flag without actually removing index tuples whose LP_DEAD-bit was set recently, after the VACUUM operation began but before it reached the leaf page in question). Note that this isn't a big behavioral change compared to PostgreSQL 13. We were already checking for set LP_DEAD bits regardless of whether the BTP_HAS_GARBAGE page level flag was set before we considered doing a deduplication pass. This commit only goes slightly further by doing the same check for all indexes, even indexes where deduplication won't be performed. We don't completely remove the BTP_HAS_GARBAGE flag. We still rely on it as a gating condition with pg_upgrade'd indexes from before B-tree version 4/PostgreSQL 12. That makes sense because we sometimes have to make a choice among pages full of duplicates when inserting a tuple with pre version 4 indexes. It probably still pays to avoid accessing the line pointer array of a page there, since it won't yet be clear whether we'll insert on to the page in question at all, let alone split it as a result. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wz%3DYpc1PDdk8OVJDChGJBjT06%3DA0Mbv9HyTLCsOknGcUFg%40mail.gmail.com |
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| .. | ||
| amapi.h | ||
| amvalidate.h | ||
| attmap.h | ||
| attnum.h | ||
| brin.h | ||
| brin_internal.h | ||
| brin_page.h | ||
| brin_pageops.h | ||
| brin_revmap.h | ||
| brin_tuple.h | ||
| brin_xlog.h | ||
| bufmask.h | ||
| clog.h | ||
| commit_ts.h | ||
| detoast.h | ||
| genam.h | ||
| generic_xlog.h | ||
| gin.h | ||
| gin_private.h | ||
| ginblock.h | ||
| ginxlog.h | ||
| gist.h | ||
| gist_private.h | ||
| gistscan.h | ||
| gistxlog.h | ||
| hash.h | ||
| hash_xlog.h | ||
| heapam.h | ||
| heapam_xlog.h | ||
| heaptoast.h | ||
| hio.h | ||
| htup.h | ||
| htup_details.h | ||
| itup.h | ||
| multixact.h | ||
| nbtree.h | ||
| nbtxlog.h | ||
| parallel.h | ||
| printsimple.h | ||
| printtup.h | ||
| relation.h | ||
| reloptions.h | ||
| relscan.h | ||
| rewriteheap.h | ||
| rmgr.h | ||
| rmgrlist.h | ||
| sdir.h | ||
| session.h | ||
| skey.h | ||
| slru.h | ||
| spgist.h | ||
| spgist_private.h | ||
| spgxlog.h | ||
| stratnum.h | ||
| subtrans.h | ||
| syncscan.h | ||
| sysattr.h | ||
| table.h | ||
| tableam.h | ||
| timeline.h | ||
| toast_helper.h | ||
| toast_internals.h | ||
| transam.h | ||
| tsmapi.h | ||
| tupconvert.h | ||
| tupdesc.h | ||
| tupdesc_details.h | ||
| tupmacs.h | ||
| twophase.h | ||
| twophase_rmgr.h | ||
| valid.h | ||
| visibilitymap.h | ||
| xact.h | ||
| xlog.h | ||
| xlog_internal.h | ||
| xlogarchive.h | ||
| xlogdefs.h | ||
| xloginsert.h | ||
| xlogreader.h | ||
| xlogrecord.h | ||
| xlogutils.h | ||