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Make min_wal_size/max_wal_size use MB internally

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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
This commit is contained in:
Simon Riggs 2017-04-04 18:00:01 -04:00
parent cd740c0dbf
commit 9a3215026b
4 changed files with 30 additions and 28 deletions
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22
src/backend/access/transam/xlog.c
View File

@ -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* Private, possibly out-of-date copy of shared LogwrtResult.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

30
src/backend/utils/misc/guc.c
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@ -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;

4
src/include/access/xlog.h
View File

@ -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;

2
src/include/utils/guc.h
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@ -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 */