From: Simon Riggs <simon@2ndQuadrant.com>
Date: Tue, 4 Apr 2017 22:00:01 +0000 (-0400)
Subject: Make min_wal_size/max_wal_size use MB internally
X-Git-Tag: REL_10_BETA1~388
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9a3215026bd6955e88bd8c20542cfe6acffdb1c8;p=postgresql
Make min_wal_size/max_wal_size use MB internally
Previously they were defined using multiples of XLogSegSize.
Remove GUC_UNIT_XSEGS. Introduce GUC_UNIT_MB
Extracted from patch series on XLogSegSize infrastructure.
Beena Emerson
---
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 287b3b1379..45ed58ea34 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -86,8 +86,8 @@ extern uint32 bootstrap_data_checksum_version;
/* User-settable parameters */
-int max_wal_size = 64; /* 1 GB */
-int min_wal_size = 5; /* 80 MB */
+int max_wal_size_mb = 1024; /* 1 GB */
+int min_wal_size_mb = 80; /* 80 MB */
int wal_keep_segments = 0;
int XLOGbuffers = -1;
int XLogArchiveTimeout = 0;
@@ -738,6 +738,10 @@ static ControlFileData *ControlFile = NULL;
#define UsableBytesInPage (XLOG_BLCKSZ - SizeOfXLogShortPHD)
#define UsableBytesInSegment ((XLOG_SEG_SIZE / XLOG_BLCKSZ) * UsableBytesInPage - (SizeOfXLogLongPHD - SizeOfXLogShortPHD))
+/* Convert min_wal_size_mb and max wal_size_mb to equivalent segment count */
+#define ConvertToXSegs(x) \
+ (x / (XLOG_SEG_SIZE / (1024 * 1024)))
+
/*
* Private, possibly out-of-date copy of shared LogwrtResult.
* See discussion above.
@@ -2200,7 +2204,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
}
/*
- * Calculate CheckPointSegments based on max_wal_size and
+ * Calculate CheckPointSegments based on max_wal_size_mb and
* checkpoint_completion_target.
*/
static void
@@ -2210,14 +2214,14 @@ CalculateCheckpointSegments(void)
/*-------
* Calculate the distance at which to trigger a checkpoint, to avoid
- * exceeding max_wal_size. This is based on two assumptions:
+ * exceeding max_wal_size_mb. This is based on two assumptions:
*
* a) we keep WAL for two checkpoint cycles, back to the "prev" checkpoint.
* b) during checkpoint, we consume checkpoint_completion_target *
* number of segments consumed between checkpoints.
*-------
*/
- target = (double) max_wal_size / (2.0 + CheckPointCompletionTarget);
+ target = (double) ConvertToXSegs(max_wal_size_mb) / (2.0 + CheckPointCompletionTarget);
/* round down */
CheckPointSegments = (int) target;
@@ -2229,7 +2233,7 @@ CalculateCheckpointSegments(void)
void
assign_max_wal_size(int newval, void *extra)
{
- max_wal_size = newval;
+ max_wal_size_mb = newval;
CalculateCheckpointSegments();
}
@@ -2253,12 +2257,12 @@ XLOGfileslop(XLogRecPtr PriorRedoPtr)
XLogSegNo recycleSegNo;
/*
- * Calculate the segment numbers that min_wal_size and max_wal_size
+ * Calculate the segment numbers that min_wal_size_mb and max_wal_size_mb
* correspond to. Always recycle enough segments to meet the minimum, and
* remove enough segments to stay below the maximum.
*/
- minSegNo = PriorRedoPtr / XLOG_SEG_SIZE + min_wal_size - 1;
- maxSegNo = PriorRedoPtr / XLOG_SEG_SIZE + max_wal_size - 1;
+ minSegNo = PriorRedoPtr / XLOG_SEG_SIZE + ConvertToXSegs(min_wal_size_mb) - 1;
+ maxSegNo = PriorRedoPtr / XLOG_SEG_SIZE + ConvertToXSegs(max_wal_size_mb) - 1;
/*
* Between those limits, recycle enough segments to get us through to the
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8b5f064d4e..a57b175b2d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -729,6 +729,11 @@ static const unit_conversion memory_unit_conversion_table[] =
{"MB", GUC_UNIT_KB, 1024},
{"kB", GUC_UNIT_KB, 1},
+ {"TB", GUC_UNIT_MB, 1024 * 1024},
+ {"GB", GUC_UNIT_MB, 1024},
+ {"MB", GUC_UNIT_MB, 1},
+ {"kB", GUC_UNIT_MB, -1024},
+
{"TB", GUC_UNIT_BLOCKS, (1024 * 1024 * 1024) / (BLCKSZ / 1024)},
{"GB", GUC_UNIT_BLOCKS, (1024 * 1024) / (BLCKSZ / 1024)},
{"MB", GUC_UNIT_BLOCKS, 1024 / (BLCKSZ / 1024)},
@@ -739,11 +744,6 @@ static const unit_conversion memory_unit_conversion_table[] =
{"MB", GUC_UNIT_XBLOCKS, 1024 / (XLOG_BLCKSZ / 1024)},
{"kB", GUC_UNIT_XBLOCKS, -(XLOG_BLCKSZ / 1024)},
- {"TB", GUC_UNIT_XSEGS, (1024 * 1024 * 1024) / (XLOG_SEG_SIZE / 1024)},
- {"GB", GUC_UNIT_XSEGS, (1024 * 1024) / (XLOG_SEG_SIZE / 1024)},
- {"MB", GUC_UNIT_XSEGS, -(XLOG_SEG_SIZE / (1024 * 1024))},
- {"kB", GUC_UNIT_XSEGS, -(XLOG_SEG_SIZE / 1024)},
-
{""} /* end of table marker */
};
@@ -2236,10 +2236,10 @@ static struct config_int ConfigureNamesInt[] =
{"min_wal_size", PGC_SIGHUP, WAL_CHECKPOINTS,
gettext_noop("Sets the minimum size to shrink the WAL to."),
NULL,
- GUC_UNIT_XSEGS
+ GUC_UNIT_MB
},
- &min_wal_size,
- 5, 2, INT_MAX,
+ &min_wal_size_mb,
+ 5 * (XLOG_SEG_SIZE/ (1024 * 1024)), 2, MAX_KILOBYTES,
NULL, NULL, NULL
},
@@ -2247,10 +2247,10 @@ static struct config_int ConfigureNamesInt[] =
{"max_wal_size", PGC_SIGHUP, WAL_CHECKPOINTS,
gettext_noop("Sets the WAL size that triggers a checkpoint."),
NULL,
- GUC_UNIT_XSEGS
+ GUC_UNIT_MB
},
- &max_wal_size,
- 64, 2, INT_MAX,
+ &max_wal_size_mb,
+ 64 * (XLOG_SEG_SIZE/ (1024 * 1024)), 2, MAX_KILOBYTES,
NULL, assign_max_wal_size, NULL
},
@@ -8085,6 +8085,9 @@ GetConfigOptionByNum(int varnum, const char **values, bool *noshow)
case GUC_UNIT_KB:
values[2] = "kB";
break;
+ case GUC_UNIT_MB:
+ values[2] = "MB";
+ break;
case GUC_UNIT_BLOCKS:
snprintf(buffer, sizeof(buffer), "%dkB", BLCKSZ / 1024);
values[2] = pstrdup(buffer);
@@ -8093,11 +8096,6 @@ GetConfigOptionByNum(int varnum, const char **values, bool *noshow)
snprintf(buffer, sizeof(buffer), "%dkB", XLOG_BLCKSZ / 1024);
values[2] = pstrdup(buffer);
break;
- case GUC_UNIT_XSEGS:
- snprintf(buffer, sizeof(buffer), "%dMB",
- XLOG_SEG_SIZE / (1024 * 1024));
- values[2] = pstrdup(buffer);
- break;
case GUC_UNIT_MS:
values[2] = "ms";
break;
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d4abf94862..d23aab589e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -94,8 +94,8 @@ extern PGDLLIMPORT XLogRecPtr XactLastCommitEnd;
extern bool reachedConsistency;
/* these variables are GUC parameters related to XLOG */
-extern int min_wal_size;
-extern int max_wal_size;
+extern int min_wal_size_mb;
+extern int max_wal_size_mb;
extern int wal_keep_segments;
extern int XLOGbuffers;
extern int XLogArchiveTimeout;
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 7dd378026a..87d0741084 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -218,7 +218,7 @@ typedef enum
#define GUC_UNIT_KB 0x1000 /* value is in kilobytes */
#define GUC_UNIT_BLOCKS 0x2000 /* value is in blocks */
#define GUC_UNIT_XBLOCKS 0x3000 /* value is in xlog blocks */
-#define GUC_UNIT_XSEGS 0x4000 /* value is in xlog segments */
+#define GUC_UNIT_MB 0x4000 /* value is in megabytes */
#define GUC_UNIT_MEMORY 0xF000 /* mask for size-related units */
#define GUC_UNIT_MS 0x10000 /* value is in milliseconds */