NotificationsYou must be signed in to change notification settings
Fork6
Star31

Commit011d60c

committed

Speed up uuid_out() by not relying on a StringInfo

Since the size of the string representation of an uuid is fixed, thereis no benefit in using a StringInfo. This commit simplifies uuid_oud()to not rely on a StringInfo, where avoiding the overhead of the stringmanipulation makes the function substantially faster.A COPY TO on a relation with one UUID attribute can show up to a 40%speedup when the bottleneck is the COPY computation with uuid_out()showing up at the top of the profiles (numbered measure here, Laurenzhas mentioned something closer to 20% faster runtimes), for example whenthe data is fully in shared buffers or the OS cache.Author: Laurenz AlbeReviewed-by: Andres Freund, Michael PaquierDescription:https://postgr.es/m/679d5455cbbb0af667ccb753da51a475bae1eaed.camel@cybertec.at

1 parent943f7ae commit011d60cCopy full SHA for 011d60c

File tree

1 file changed

+10

-6

lines changed

src/backend/utils/adt
- uuid.c

1 file changed

+10

-6

lines changed

`‎src/backend/utils/adt/uuid.c`

Lines changed: 10 additions & 6 deletions

Original file line number	Diff line number	Diff line change
`@@ -53,10 +53,13 @@ uuid_out(PG_FUNCTION_ARGS)`
`53`	`53`	`{`
`54`	`54`	`pg_uuid_t*uuid=PG_GETARG_UUID_P(0);`
`55`	`55`	`staticconstcharhex_chars[]="0123456789abcdef";`
`56`		`-StringInfoDatabuf;`
	`56`	`+char*buf,`
	`57`	`+*p;`
`57`	`58`	`inti;`
`58`	`59`
`59`		`-initStringInfo(&buf);`
	`60`	`+/* counts for the four hyphens and the zero-terminator */`
	`61`	`+buf=palloc(2*UUID_LEN+5);`
	`62`	`+p=buf;`
`60`	`63`	`for (i=0;i<UUID_LEN;i++)`
`61`	`64`	`{`
`62`	`65`	`inthi;`
`@@ -68,16 +71,17 @@ uuid_out(PG_FUNCTION_ARGS)`
`68`	`71`	`* ("-"). Therefore, add the hyphens at the appropriate places here.`
`69`	`72`	`*/`
`70`	`73`	`if (i==4\|\|i==6\|\|i==8\|\|i==10)`
`71`		`-appendStringInfoChar(&buf,'-');`
	`74`	`+*p++='-';`
`72`	`75`
`73`	`76`	`hi=uuid->data[i] >>4;`
`74`	`77`	`lo=uuid->data[i]&0x0F;`
`75`	`78`
`76`		`-appendStringInfoChar(&buf,hex_chars[hi]);`
`77`		`-appendStringInfoChar(&buf,hex_chars[lo]);`
	`79`	`+*p++=hex_chars[hi];`
	`80`	`+*p++=hex_chars[lo];`
`78`	`81`	`}`
	`82`	`+*p='\0';`
`79`	`83`
`80`		`-PG_RETURN_CSTRING(buf.data);`
	`84`	`+PG_RETURN_CSTRING(buf);`
`81`	`85`	`}`
`82`	`86`
`83`	`87`	`/*`

0 commit comments

Comments

(0)

Movatterモバイル変換

Navigation Menu

Search code, repositories, users, issues, pull requests...

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Commit011d60c

File tree

1 file changed

1 file changed

`‎src/backend/utils/adt/uuid.c`

0 commit comments