Large last written lsn cache (#177)

Maintain cache of last written LSN for each relation segment (8 Mb).

contrib/neon/pagestore_smgr.c

@@ -84,6 +84,11 @@ static char *hexdump_page(char *page);
 
 const int	SmgrTrace = DEBUG5;
 
+/*
+ * Pseudo block number used to associate LSN with relation metadata (relation size)
+ */
+#define REL_METADATA_PSEUDO_BLOCKNO InvalidBlockNumber
+
 page_server_api *page_server;
 
 /* GUCs */
@@ -558,7 +563,7 @@ zenith_wallog_page(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	 * Remember the LSN on this page. When we read the page again, we must
 	 * read the same or newer version of it.
 	 */
-	SetLastWrittenPageLSN(lsn);
+	SetLastWrittenLSN(lsn, reln->smgr_rnode.node.relNode, blocknum, blocknum);
 }
 
 
@@ -603,7 +608,7 @@ zm_adjust_lsn(XLogRecPtr lsn)
  * Return LSN for requesting pages and number of blocks from page server
  */
 static XLogRecPtr
-zenith_get_request_lsn(bool *latest)
+zenith_get_request_lsn(bool *latest, Oid rnode, BlockNumber blkno)
 {
 	XLogRecPtr	lsn;
 
@@ -630,9 +635,9 @@ zenith_get_request_lsn(bool *latest)
 		 * so our request cannot concern those.
 		 */
 		*latest = true;
-		lsn = GetLastWrittenPageLSN();
+		lsn = GetLastWrittenLSN(rnode, blkno);
 		Assert(lsn != InvalidXLogRecPtr);
-		elog(DEBUG1, "zenith_get_request_lsn GetLastWrittenPageLSN lsn %X/%X ",
+		elog(DEBUG1, "zenith_get_request_lsn GetLastWrittenLSN lsn %X/%X ",
 			 (uint32) ((lsn) >> 32), (uint32) (lsn));
 
 		lsn = zm_adjust_lsn(lsn);
@@ -716,7 +721,7 @@ zenith_exists(SMgrRelation reln, ForkNumber forkNum)
 		return false;
 	}
 
-	request_lsn = zenith_get_request_lsn(&latest);
+	request_lsn = zenith_get_request_lsn(&latest, reln->smgr_rnode.node.relNode, REL_METADATA_PSEUDO_BLOCKNO);
 	{
 		ZenithExistsRequest request = {
 			.req.tag = T_ZenithExistsRequest,
@@ -791,7 +796,7 @@ zenith_create(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
 	 *
 	 * FIXME: This is currently not just an optimization, but required for
 	 * correctness. Postgres can call smgrnblocks() on the newly-created
-	 * relation. Currently, we don't call SetLastWrittenPageLSN() when a new
+	 * relation. Currently, we don't call SetLastWrittenLSN() when a new
 	 * relation created, so if we didn't remember the size in the relsize
 	 * cache, we might call smgrnblocks() on the newly-created relation before
 	 * the creation WAL record hass been received by the page server.
@@ -904,6 +909,8 @@ zenith_extend(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno,
 	if (IS_LOCAL_REL(reln))
 		mdextend(reln, forkNum, blkno, buffer, skipFsync);
 #endif
+
+	SetLastWrittenLSN(lsn, reln->smgr_rnode.node.relNode, REL_METADATA_PSEUDO_BLOCKNO, REL_METADATA_PSEUDO_BLOCKNO);
 }
 
 /*
@@ -1079,7 +1086,7 @@ zenith_read(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno,
 			elog(ERROR, "unknown relpersistence '%c'", reln->smgr_relpersistence);
 	}
 
-	request_lsn = zenith_get_request_lsn(&latest);
+	request_lsn = zenith_get_request_lsn(&latest, reln->smgr_rnode.node.relNode, blkno);
 	zenith_read_at_lsn(reln->smgr_rnode.node, forkNum, blkno, request_lsn, latest, buffer);
 
 #ifdef DEBUG_COMPARE_LOCAL
@@ -1284,7 +1291,7 @@ zenith_nblocks(SMgrRelation reln, ForkNumber forknum)
 		return n_blocks;
 	}
 
-	request_lsn = zenith_get_request_lsn(&latest);
+	request_lsn = zenith_get_request_lsn(&latest, reln->smgr_rnode.node.relNode, REL_METADATA_PSEUDO_BLOCKNO);
 	{
 		ZenithNblocksRequest request = {
 			.req.tag = T_ZenithNblocksRequest,
@@ -1344,7 +1351,7 @@ zenith_dbsize(Oid dbNode)
 	XLogRecPtr request_lsn;
 	bool		latest;
 
-	request_lsn = zenith_get_request_lsn(&latest);
+	request_lsn = zenith_get_request_lsn(&latest, InvalidOid, REL_METADATA_PSEUDO_BLOCKNO);
 	{
 		ZenithDbSizeRequest request = {
 			.req.tag = T_ZenithDbSizeRequest,
@@ -1431,7 +1438,11 @@ zenith_truncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
 	 */
 	XLogFlush(lsn);
 
-	SetLastWrittenPageLSN(lsn);
+	/*
+	 * Truncate may affect several chunks of relations. So we should either update last written LSN for all of them,
+	 * either update LSN for "dummy" metadata block. Second approach seems to be more efficient.
+	 */
+	SetLastWrittenLSN(lsn, reln->smgr_rnode.node.relNode, REL_METADATA_PSEUDO_BLOCKNO, REL_METADATA_PSEUDO_BLOCKNO);
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (IS_LOCAL_REL(reln))

src/backend/access/gin/gininsert.c

@@ -421,8 +421,8 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 		log_newpage_range(index, MAIN_FORKNUM,
 						  0, RelationGetNumberOfBlocks(index),
 						  true);
+		SetLastWrittenLSN(XactLastRecEnd, index->rd_smgr->smgr_rnode.node.relNode, 0, RelationGetNumberOfBlocks(index));
 	}
-	SetLastWrittenPageLSN(XactLastRecEnd);
 
 	smgr_end_unlogged_build(index->rd_smgr);
 

src/backend/access/gist/gistbuild.c

@@ -335,9 +335,10 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 			log_newpage_range(index, MAIN_FORKNUM,
 							  0, RelationGetNumberOfBlocks(index),
 							  true);
+			SetLastWrittenLSN(XactLastRecEnd,
+							  index->rd_smgr->smgr_rnode.node.relNode,
+							  0, RelationGetNumberOfBlocks(index));
 		}
-		SetLastWrittenPageLSN(XactLastRecEnd);
-
 		smgr_end_unlogged_build(index->rd_smgr);
 	}
 
@@ -467,7 +468,8 @@ gist_indexsortbuild(GISTBuildState *state)
 
 		lsn = log_newpage(&state->indexrel->rd_node, MAIN_FORKNUM, GIST_ROOT_BLKNO,
 					pagestate->page, true);
-		SetLastWrittenPageLSN(lsn);
+		SetLastWrittenLSN(lsn, state->indexrel->rd_smgr->smgr_rnode.node.relNode,
+							  GIST_ROOT_BLKNO, GIST_ROOT_BLKNO);
 	}
 
 	pfree(pagestate->page);

src/backend/access/spgist/spginsert.c

@@ -143,8 +143,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 		log_newpage_range(index, MAIN_FORKNUM,
 						  0, RelationGetNumberOfBlocks(index),
 						  true);
+		SetLastWrittenLSN(XactLastRecEnd, index->rd_smgr->smgr_rnode.node.relNode,
+						  0, RelationGetNumberOfBlocks(index));
 	}
-	SetLastWrittenPageLSN(XactLastRecEnd);
 
 	smgr_end_unlogged_build(index->rd_smgr);