Adding more trigrams makes post query worse

[GoogleCodeExporter]

bash$ csearch -i -verbose '%%0.*sprintf'
2012/02/29 16:02:11 query: "%%0" 
("SPR"|"SPr"|"SpR"|"Spr"|"sPR"|"sPr"|"spR"|"spr")|("\xbfPR" "ſP")|("\xbfPr" 
"ſP")|("\xbfpR" "ſp")|("\xbfpr" "ſp") 
("PRI"|"PRi"|"PrI"|"Pri"|"pRI"|"pRi"|"prI"|"pri") 
("RIN"|"RIn"|"RiN"|"Rin"|"rIN"|"rIn"|"riN"|"rin") 
("INT"|"INt"|"InT"|"Int"|"iNT"|"iNt"|"inT"|"int") 
("NTF"|"NTf"|"NtF"|"Ntf"|"nTF"|"nTf"|"ntF"|"ntf")
2012/02/29 16:02:11 post query identified 3295 possible files
bash$ csearch -i -verbose '%%0' >/dev/null
2012/02/29 16:02:24 query: "%%0"
2012/02/29 16:02:24 post query identified 9 possible files

Since only 9 files match '%%0', I would expect no more than 9 possible files 
from the post query when adding '.*sprintf' to the query string.  It looks like 
something is ignoring the 'restrict' list somewhere.

I'm still working on a minimal test case.  I'll look into this more tonight or 
so.

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Original issue reported on code.google.com by dgryski on 29 Feb 2012 at 3:10

[GoogleCodeExporter]

postReader init() was not initializing restrict correctly, so all r.next() 
calls returned the full list list and not the restricted set.

Patch attached.

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Original comment by dgryski on 29 Feb 2012 at 3:43

Attachments:

• restrict.patch

[GoogleCodeExporter]

With this fix, the 599 files matching 'hello world' in linux-3.1.3 example ( 
http://swtch.com/~rsc/regexp/regexp4.html ) is reduced to 32:

/tmp dgryski$ CSEARCHINDEX=/tmp/.csearch-linux csearch -verbose -i -c 'hello 
world' 
2012/03/07 11:45:20 query: ("HEL"|"HEl"|"HeL"|"Hel"|"hEL"|"hEl"|"heL"|"hel") 
("ELL"|"ELl"|"ElL"|"Ell"|"eLL"|"eLl"|"elL"|"ell") 
("LLO"|"LLo"|"LlO"|"Llo"|"lLO"|"lLo"|"llO"|"llo") ("LO "|"Lo "|"lO "|"lo ") ("O 
W"|"O w"|"o W"|"o w") (" WO"|" Wo"|" wO"|" wo") 
("WOR"|"WOr"|"WoR"|"Wor"|"wOR"|"wOr"|"woR"|"wor") 
("ORL"|"ORl"|"OrL"|"Orl"|"oRL"|"oRl"|"orL"|"orl") 
("RLD"|"RLd"|"RlD"|"Rld"|"rLD"|"rLd"|"rlD"|"rld")
2012/03/07 11:45:20 post query identified 32 possible files
/tmp/linux-3.1.3/Documentation/filesystems/ramfs-rootfs-initramfs.txt: 3
/tmp/linux-3.1.3/Documentation/java.txt: 1
/tmp/linux-3.1.3/Documentation/s390/Debugging390.txt: 3
/tmp/linux-3.1.3/arch/blackfin/kernel/kgdb_test.c: 1
/tmp/linux-3.1.3/arch/frv/kernel/gdb-stub.c: 1
/tmp/linux-3.1.3/arch/mn10300/kernel/gdb-stub.c: 1
/tmp/linux-3.1.3/arch/powerpc/platforms/powermac/udbg_scc.c: 1
/tmp/linux-3.1.3/drivers/media/video/msp3400-driver.c: 1
/tmp/linux-3.1.3/drivers/net/sfc/selftest.c: 1
/tmp/linux-3.1.3/samples/kdb/kdb_hello.c: 2

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Original comment by dgryski on 7 Mar 2012 at 10:48

[GoogleCodeExporter]

This issue was closed by revision dbeef1612f35.

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Original comment by dgryski on 2 May 2012 at 8:02

• Changed state: Fixed