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Optimize Query jumble

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f31aad9b0 adjusted query jumbling so it no longer ignores NULL nodes
during the jumble.  This added some overhead.  Here we tune a few
things to make jumbling faster again.  This makes jumbling perform
similar or even slightly faster than prior to that change.

Author: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CAApHDvreP04nhTKuYsPw0F-YN+4nr4f=L72SPeFb81jfv+2c7w@mail.gmail.com
This commit is contained in:
David Rowley 2025-03-27 18:34:34 +13:00
parent f31aad9b07
commit ad9a23bc4f
1 changed files with 95 additions and 9 deletions
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104
src/backend/nodes/queryjumblefuncs.c
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@ -218,6 +218,8 @@ DoJumble(JumbleState *jstate, Node *node)
/*
* AppendJumbleInternal: Internal function for appending to the jumble buffer
*
* Note: Callers must ensure that size > 0.
*/
static pg_attribute_always_inline void
AppendJumbleInternal(JumbleState *jstate, const unsigned char *item,
@ -226,16 +228,36 @@ AppendJumbleInternal(JumbleState *jstate, const unsigned char *item,
unsigned char *jumble = jstate->jumble;
Size jumble_len = jstate->jumble_len;
/* Ensure the caller didn't mess up */
Assert(size > 0);
/*
* Fast path for when there's enough space left in the buffer. This is
* worthwhile as means the memcpy can be inlined into very efficient code
* when 'size' is a compile-time constant.
*/
if (likely(size <= JUMBLE_SIZE - jumble_len))
{
memcpy(jumble + jumble_len, item, size);
jstate->jumble_len += size;
#ifdef USE_ASSERT_CHECKING
jstate->total_jumble_len += size;
#endif
return;
}
/*
* Whenever the jumble buffer is full, we hash the current contents and
* reset the buffer to contain just that hash value, thus relying on the
* hash to summarize everything so far.
*/
while (size > 0)
do
{
Size part_size;
if (jumble_len >= JUMBLE_SIZE)
if (unlikely(jumble_len >= JUMBLE_SIZE))
{
uint64 start_hash;
@ -253,7 +275,7 @@ AppendJumbleInternal(JumbleState *jstate, const unsigned char *item,
#ifdef USE_ASSERT_CHECKING
jstate->total_jumble_len += part_size;
#endif
}
} while (size > 0);
jstate->jumble_len = jumble_len;
}
@ -281,6 +303,61 @@ AppendJumbleNull(JumbleState *jstate)
jstate->pending_nulls++;
}
/*
* AppendJumble8
* Add the first byte from the given 'value' pointer to the jumble state
*/
static pg_noinline void
AppendJumble8(JumbleState *jstate, const unsigned char *value)
{
if (jstate->pending_nulls > 0)
FlushPendingNulls(jstate);
AppendJumbleInternal(jstate, value, 1);
}
/*
* AppendJumble16
* Add the first 2 bytes from the given 'value' pointer to the jumble
* state.
*/
static pg_noinline void
AppendJumble16(JumbleState *jstate, const unsigned char *value)
{
if (jstate->pending_nulls > 0)
FlushPendingNulls(jstate);
AppendJumbleInternal(jstate, value, 2);
}
/*
* AppendJumble32
* Add the first 4 bytes from the given 'value' pointer to the jumble
* state.
*/
static pg_noinline void
AppendJumble32(JumbleState *jstate, const unsigned char *value)
{
if (jstate->pending_nulls > 0)
FlushPendingNulls(jstate);
AppendJumbleInternal(jstate, value, 4);
}
/*
* AppendJumble64
* Add the first 8 bytes from the given 'value' pointer to the jumble
* state.
*/
static pg_noinline void
AppendJumble64(JumbleState *jstate, const unsigned char *value)
{
if (jstate->pending_nulls > 0)
FlushPendingNulls(jstate);
AppendJumbleInternal(jstate, value, 8);
}
/*
* FlushPendingNulls
* Incorporate the pending_null value into the jumble buffer.
@ -417,9 +494,18 @@ IsSquashableConstList(List *elements, Node **firstExpr, Node **lastExpr)
#define JUMBLE_LOCATION(location) \
RecordConstLocation(jstate, expr->location, false)
#define JUMBLE_FIELD(item) \
AppendJumble(jstate, (const unsigned char *) &(expr->item), sizeof(expr->item))
#define JUMBLE_FIELD_SINGLE(item) \
AppendJumble(jstate, (const unsigned char *) &(item), sizeof(item))
do { \
if (sizeof(expr->item) == 8) \
AppendJumble64(jstate, (const unsigned char *) &(expr->item)); \
else if (sizeof(expr->item) == 4) \
AppendJumble32(jstate, (const unsigned char *) &(expr->item)); \
else if (sizeof(expr->item) == 2) \
AppendJumble16(jstate, (const unsigned char *) &(expr->item)); \
else if (sizeof(expr->item) == 1) \
AppendJumble8(jstate, (const unsigned char *) &(expr->item)); \
else \
AppendJumble(jstate, (const unsigned char *) &(expr->item), sizeof(expr->item)); \
} while (0)
#define JUMBLE_STRING(str) \
do { \
if (expr->str) \
@ -551,15 +637,15 @@ _jumbleList(JumbleState *jstate, Node *node)
break;
case T_IntList:
foreach(l, expr)
JUMBLE_FIELD_SINGLE(lfirst_int(l));
AppendJumble32(jstate, (const unsigned char *) &lfirst_int(l));
break;
case T_OidList:
foreach(l, expr)
JUMBLE_FIELD_SINGLE(lfirst_oid(l));
AppendJumble32(jstate, (const unsigned char *) &lfirst_oid(l));
break;
case T_XidList:
foreach(l, expr)
JUMBLE_FIELD_SINGLE(lfirst_xid(l));
AppendJumble32(jstate, (const unsigned char *) &lfirst_xid(l));
break;
default:
elog(ERROR, "unrecognized list node type: %d",