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Compress GIN posting lists, for smaller index size.

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GIN posting lists are now encoded using varbyte-encoding, which allows them
to fit in much smaller space than the straight ItemPointer array format used
before. The new encoding is used for both the lists stored in-line in entry
tree items, and in posting tree leaf pages.

To maintain backwards-compatibility and keep pg_upgrade working, the code
can still read old-style pages and tuples. Posting tree leaf pages in the
new format are flagged with GIN_COMPRESSED flag, to distinguish old and new
format pages. Likewise, entry tree tuples in the new format have a
GIN_ITUP_COMPRESSED flag set in a bit that was previously unused.

This patch bumps GIN_CURRENT_VERSION from 1 to 2. New indexes created with
version 9.4 will therefore have version number 2 in the metapage, while old
pg_upgraded indexes will have version 1. The code treats them the same, but
it might be come handy in the future, if we want to drop support for the
uncompressed format.

Alexander Korotkov and me. Reviewed by Tomas Vondra and Amit Langote.
This commit is contained in:
Heikki Linnakangas
2014-01-22 18:51:48 +02:00
parent 243ee26633
commit 36a35c550a
13 changed files with 2359 additions and 768 deletions
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45
src/backend/access/rmgrdesc/gindesc.c
View File

@@ -47,8 +47,7 @@ gin_desc(StringInfo buf, uint8 xl_info, char *rec)
appendStringInfoString(buf, "Insert item, ");
desc_node(buf, xlrec->node, xlrec->blkno);
appendStringInfo(buf, " offset: %u isdata: %c isleaf: %c",
xlrec->offset,
appendStringInfo(buf, " isdata: %c isleaf: %c",
(xlrec->flags & GIN_INSERT_ISDATA) ? 'T' : 'F',
(xlrec->flags & GIN_INSERT_ISLEAF) ? 'T' : 'F');
if (!(xlrec->flags & GIN_INSERT_ISLEAF))
@@ -67,24 +66,50 @@ gin_desc(StringInfo buf, uint8 xl_info, char *rec)
appendStringInfo(buf, " isdelete: %c",
(((ginxlogInsertEntry *) payload)->isDelete) ? 'T' : 'F');
else if (xlrec->flags & GIN_INSERT_ISLEAF)
appendStringInfo(buf, " nitem: %u",
(((ginxlogInsertDataLeaf *) payload)->nitem));
{
ginxlogRecompressDataLeaf *insertData =
(ginxlogRecompressDataLeaf *) payload;
appendStringInfo(buf, " unmodified: %u length: %u (compressed)",
insertData->unmodifiedsize,
insertData->length);
}
else
{
ginxlogInsertDataInternal *insertData = (ginxlogInsertDataInternal *) payload;
appendStringInfo(buf, " pitem: %u-%u/%u",
PostingItemGetBlockNumber((PostingItem *) payload),
ItemPointerGetBlockNumber(&((PostingItem *) payload)->key),
ItemPointerGetOffsetNumber(&((PostingItem *) payload)->key));
PostingItemGetBlockNumber(&insertData->newitem),
ItemPointerGetBlockNumber(&insertData->newitem.key),
ItemPointerGetOffsetNumber(&insertData->newitem.key));
}
}
break;
case XLOG_GIN_SPLIT:
appendStringInfoString(buf, "Page split, ");
desc_node(buf, ((ginxlogSplit *) rec)->node, ((ginxlogSplit *) rec)->lblkno);
appendStringInfo(buf, " isrootsplit: %c", (((ginxlogSplit *) rec)->flags & GIN_SPLIT_ROOT) ? 'T' : 'F');
{
ginxlogSplit *xlrec = (ginxlogSplit *) rec;
appendStringInfoString(buf, "Page split, ");
desc_node(buf, ((ginxlogSplit *) rec)->node, ((ginxlogSplit *) rec)->lblkno);
appendStringInfo(buf, " isrootsplit: %c", (((ginxlogSplit *) rec)->flags & GIN_SPLIT_ROOT) ? 'T' : 'F');
appendStringInfo(buf, " isdata: %c isleaf: %c",
(xlrec->flags & GIN_INSERT_ISDATA) ? 'T' : 'F',
(xlrec->flags & GIN_INSERT_ISLEAF) ? 'T' : 'F');
}
break;
case XLOG_GIN_VACUUM_PAGE:
appendStringInfoString(buf, "Vacuum page, ");
desc_node(buf, ((ginxlogVacuumPage *) rec)->node, ((ginxlogVacuumPage *) rec)->blkno);
break;
case XLOG_GIN_VACUUM_DATA_LEAF_PAGE:
{
ginxlogVacuumDataLeafPage *xlrec = (ginxlogVacuumDataLeafPage *) rec;
appendStringInfoString(buf, "Vacuum data leaf page, ");
desc_node(buf, xlrec->node, xlrec->blkno);
appendStringInfo(buf, " unmodified: %u length: %u",
xlrec->data.unmodifiedsize,
xlrec->data.length);
}
break;
case XLOG_GIN_DELETE_PAGE:
appendStringInfoString(buf, "Delete page, ");
desc_node(buf, ((ginxlogDeletePage *) rec)->node, ((ginxlogDeletePage *) rec)->blkno);