Determine SLRU kind in extension

Author: Konstantin Knizhnik

src/backend/access/transam/slru.c

@@ -267,15 +267,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
 	ctl->shared = shared;
 	ctl->sync_handler = sync_handler;
 	strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
-
-	if (strcmp(subdir, "pg_xact") == 0)
-		ctl->kind = SLRU_CLOG;
-	else if (strcmp(subdir, "pg_multixact/members") == 0)
-		ctl->kind = SLRU_MULTIXACT_MEMBERS;
-	else if (strcmp(subdir, "pg_multixact/offsets") == 0)
-		ctl->kind = SLRU_MULTIXACT_OFFSETS;
-	else
-		ctl->kind = SLRU_OTHER;
 }
 
 /*
@@ -637,9 +628,6 @@ SimpleLruDownloadSegment(SlruCtl ctl, int pageno, char const* path)
 
 	static SMgrRelationData dummy_smgr_rel = {0};
 
-	if (ctl->kind == SLRU_OTHER) /* Only CLOG/multixact can be downloaded from page server */
-		return -1;
-
 	/* If page is beyond latest written page, then do not try to download segment from server */
 	if (pageno > ctl->shared->latest_page_number)
 		return -1;
@@ -652,7 +640,7 @@ SimpleLruDownloadSegment(SlruCtl ctl, int pageno, char const* path)
 	segno = pageno / SLRU_PAGES_PER_SEGMENT;
 
 	buffer = palloc(BLCKSZ * SLRU_PAGES_PER_SEGMENT);
-	n_blocks = smgr_read_slru_segment(&dummy_smgr_rel, ctl->kind, segno, buffer);
+	n_blocks = smgr_read_slru_segment(&dummy_smgr_rel, path, segno, buffer);
 	if (n_blocks > 0)
 	{
 		fd = OpenTransientFile(path, O_RDWR | O_CREAT | PG_BINARY);

src/backend/storage/smgr/smgr.c

@@ -539,9 +539,9 @@ smgrwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 }
 
 int
-smgr_read_slru_segment(SMgrRelation reln, SlruKind kind, int segno, void* buffer)
+smgr_read_slru_segment(SMgrRelation reln, const char* path, int segno, void* buffer)
 {
-	return (*reln->smgr).smgr_read_slru_segment ? (*reln->smgr).smgr_read_slru_segment(reln, kind, segno, buffer) : 0;
+	return (*reln->smgr).smgr_read_slru_segment ? (*reln->smgr).smgr_read_slru_segment(reln, path, segno, buffer) : 0;
 }
 
 

src/include/access/slru.h

@@ -16,7 +16,6 @@
 #include "access/xlogdefs.h"
 #include "storage/lwlock.h"
 #include "storage/sync.h"
-#include "storage/smgr.h"
 
 
 /*
@@ -135,7 +134,6 @@ typedef struct SlruCtlData
 	 * it's always the same, it doesn't need to be in shared memory.
 	 */
 	char		Dir[64];
-	SlruKind    kind;
 } SlruCtlData;
 
 typedef SlruCtlData *SlruCtl;

src/include/storage/smgr.h

@@ -88,13 +88,6 @@ typedef SMgrRelationData *SMgrRelation;
 #define SmgrIsTemp(smgr) \
 	RelFileNodeBackendIsTemp((smgr)->smgr_rnode)
 
-typedef enum {
-	SLRU_CLOG,
-	SLRU_MULTIXACT_MEMBERS,
-	SLRU_MULTIXACT_OFFSETS,
-	SLRU_OTHER
-} SlruKind;
-
 /*
  * This struct of function pointers defines the API between smgr.c and
  * any individual storage manager module.  Note that smgr subfunctions are
@@ -136,7 +129,7 @@ typedef struct f_smgr
 	void		(*smgr_finish_unlogged_build_phase_1) (SMgrRelation reln);
 	void		(*smgr_end_unlogged_build) (SMgrRelation reln);
 
-	int  		(*smgr_read_slru_segment) (SMgrRelation reln, SlruKind kind, int segno, void* buffer);
+	int  		(*smgr_read_slru_segment) (SMgrRelation reln, const char *path, int segno, void* buffer);
 } f_smgr;
 
 typedef void (*smgr_init_hook_type) (void);
@@ -188,6 +181,6 @@ extern void smgr_start_unlogged_build(SMgrRelation reln);
 extern void	smgr_finish_unlogged_build_phase_1(SMgrRelation reln);
 extern void smgr_end_unlogged_build(SMgrRelation reln);
 
-extern int  smgr_read_slru_segment(SMgrRelation reln, SlruKind kind, int segno, void* buffer);
+extern int  smgr_read_slru_segment(SMgrRelation reln, const char *path, int segno, void* buffer);
 
 #endif							/* SMGR_H */