Thread: Where can I find the code for extern OidFunctionCall7?
OidFunctionCall7 is called from costsize.c, in function void cost_index. From
the comments, I understand that there is an indirection mechanism here to
allow for different index access methods. Looking at fmgr.h where it is
declared is not clear to me where I would ultimately find the code.
Any pointers will be greatly appreciated
/* * Call index-access-method-specific code to estimate the processing cost * for scanning the index, as well as the
selectivityof the index (ie, * the fraction of main-table tuples we will have to retrieve) and its * correlation to the
main-tabletuple order. */OidFunctionCall7(index->amcostestimate, PointerGetDatum(root),
PointerGetDatum(path), Float8GetDatum(loop_count), PointerGetDatum(&indexStartupCost),
PointerGetDatum(&indexTotalCost), PointerGetDatum(&indexSelectivity),
PointerGetDatum(&indexCorrelation));
--
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On Thu, Sep 5, 2013 at 12:38 PM, arthernan <arthernan@hotmail.com> wrote: > OidFunctionCall7 is called from costsize.c, in function void cost_index. From > the comments, I understand that there is an indirection mechanism here to > allow for different index access methods. Looking at fmgr.h where it is > declared is not clear to me where I would ultimately find the code. > > Any pointers will be greatly appreciated Use 'git grep'. It's a macro defined in fmgr.h. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
arthernan wrote: > OidFunctionCall7 is called from costsize.c, in function void cost_index. From > the comments, I understand that there is an indirection mechanism here to > allow for different index access methods. Looking at fmgr.h where it is > declared is not clear to me where I would ultimately find the code. > > Any pointers will be greatly appreciated The code you're really looking for is the amcostestimate function of the AM that the index uses. So if it's a btree you want btcostestimate, for instance. You can see the AM definitions in the pg_am system catalog and src/include/catalog/pg_am.h. > /* > * Call index-access-method-specific code to estimate the processing cost > * for scanning the index, as well as the selectivity of the index (ie, > * the fraction of main-table tuples we will have to retrieve) and its > * correlation to the main-table tuple order. > */ > OidFunctionCall7(index->amcostestimate, > PointerGetDatum(root), > PointerGetDatum(path), > Float8GetDatum(loop_count), > PointerGetDatum(&indexStartupCost), > PointerGetDatum(&indexTotalCost), > PointerGetDatum(&indexSelectivity), > PointerGetDatum(&indexCorrelation)); -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
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The comments on this sourcebase are really good, plus it is very well structured! I read somewhere that you can actually "store" an execution plan by using stored procedures. If that is the case. I would imagine that variables would prevent the histograms from being used. I don't mind finding the code myself, but... Where is the code that does that switch? Clues are welcome too!! -- View this message in context: http://postgresql.1045698.n5.nabble.com/Where-can-I-find-the-code-for-extern-OidFunctionCall7-tp5769737p5769800.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com.
Never mind I think I found it. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Where-can-I-find-the-code-for-extern-OidFunctionCall7-tp5769737p5769801.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com.