From f2dec34e19d3969ddd616e671fe9a7b968bec812 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Wed, 11 Oct 2017 16:26:35 -0700 Subject: [PATCH] Use one stringbuffer for all rows printed in printtup.c. This avoids newly allocating, and then possibly growing, the stringbuffer for every row. For wide rows this can substantially reduce memory allocator overhead, at the price of not immediately reducing memory usage after outputting an especially wide row. Author: Andres Freund Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de --- src/backend/access/common/printtup.c | 46 +++++++++++++++------------- 1 file changed, 25 insertions(+), 21 deletions(-) diff --git a/src/backend/access/common/printtup.c b/src/backend/access/common/printtup.c index 20d20e623e..c00b372b84 100644 --- a/src/backend/access/common/printtup.c +++ b/src/backend/access/common/printtup.c @@ -57,6 +57,7 @@ typedef struct typedef struct { DestReceiver pub; /* publicly-known function pointers */ + StringInfoData buf; /* output buffer */ Portal portal; /* the Portal we are printing from */ bool sendDescrip; /* send RowDescription at startup? */ TupleDesc attrinfo; /* The attr info we are set up for */ @@ -127,6 +128,9 @@ printtup_startup(DestReceiver *self, int operation, TupleDesc typeinfo) DR_printtup *myState = (DR_printtup *) self; Portal portal = myState->portal; + /* create buffer to be used for all messages */ + initStringInfo(&myState->buf); + /* * Create a temporary memory context that we can reset once per row to * recover palloc'd memory. This avoids any problems with leaks inside @@ -302,7 +306,7 @@ printtup(TupleTableSlot *slot, DestReceiver *self) TupleDesc typeinfo = slot->tts_tupleDescriptor; DR_printtup *myState = (DR_printtup *) self; MemoryContext oldcontext; - StringInfoData buf; + StringInfo buf = &myState->buf; int natts = typeinfo->natts; int i; @@ -319,9 +323,9 @@ printtup(TupleTableSlot *slot, DestReceiver *self) /* * Prepare a DataRow message (note buffer is in per-row context) */ - pq_beginmessage(&buf, 'D'); + pq_beginmessage_reuse(buf, 'D'); - pq_sendint(&buf, natts, 2); + pq_sendint(buf, natts, 2); /* * send the attributes of this tuple @@ -333,7 +337,7 @@ printtup(TupleTableSlot *slot, DestReceiver *self) if (slot->tts_isnull[i]) { - pq_sendint(&buf, -1, 4); + pq_sendint(buf, -1, 4); continue; } @@ -354,7 +358,7 @@ printtup(TupleTableSlot *slot, DestReceiver *self) char *outputstr; outputstr = OutputFunctionCall(&thisState->finfo, attr); - pq_sendcountedtext(&buf, outputstr, strlen(outputstr), false); + pq_sendcountedtext(buf, outputstr, strlen(outputstr), false); } else { @@ -362,13 +366,13 @@ printtup(TupleTableSlot *slot, DestReceiver *self) bytea *outputbytes; outputbytes = SendFunctionCall(&thisState->finfo, attr); - pq_sendint(&buf, VARSIZE(outputbytes) - VARHDRSZ, 4); - pq_sendbytes(&buf, VARDATA(outputbytes), + pq_sendint(buf, VARSIZE(outputbytes) - VARHDRSZ, 4); + pq_sendbytes(buf, VARDATA(outputbytes), VARSIZE(outputbytes) - VARHDRSZ); } } - pq_endmessage(&buf); + pq_endmessage_reuse(buf); /* Return to caller's context, and flush row's temporary memory */ MemoryContextSwitchTo(oldcontext); @@ -387,7 +391,7 @@ printtup_20(TupleTableSlot *slot, DestReceiver *self) TupleDesc typeinfo = slot->tts_tupleDescriptor; DR_printtup *myState = (DR_printtup *) self; MemoryContext oldcontext; - StringInfoData buf; + StringInfo buf = &myState->buf; int natts = typeinfo->natts; int i, j, @@ -406,7 +410,7 @@ printtup_20(TupleTableSlot *slot, DestReceiver *self) /* * tell the frontend to expect new tuple data (in ASCII style) */ - pq_beginmessage(&buf, 'D'); + pq_beginmessage_reuse(buf, 'D'); /* * send a bitmap of which attributes are not null @@ -420,13 +424,13 @@ printtup_20(TupleTableSlot *slot, DestReceiver *self) k >>= 1; if (k == 0) /* end of byte? */ { - pq_sendint(&buf, j, 1); + pq_sendint(buf, j, 1); j = 0; k = 1 << 7; } } if (k != (1 << 7)) /* flush last partial byte */ - pq_sendint(&buf, j, 1); + pq_sendint(buf, j, 1); /* * send the attributes of this tuple @@ -443,10 +447,10 @@ printtup_20(TupleTableSlot *slot, DestReceiver *self) Assert(thisState->format == 0); outputstr = OutputFunctionCall(&thisState->finfo, attr); - pq_sendcountedtext(&buf, outputstr, strlen(outputstr), true); + pq_sendcountedtext(buf, outputstr, strlen(outputstr), true); } - pq_endmessage(&buf); + pq_endmessage_reuse(buf); /* Return to caller's context, and flush row's temporary memory */ MemoryContextSwitchTo(oldcontext); @@ -572,7 +576,7 @@ printtup_internal_20(TupleTableSlot *slot, DestReceiver *self) TupleDesc typeinfo = slot->tts_tupleDescriptor; DR_printtup *myState = (DR_printtup *) self; MemoryContext oldcontext; - StringInfoData buf; + StringInfo buf = &myState->buf; int natts = typeinfo->natts; int i, j, @@ -591,7 +595,7 @@ printtup_internal_20(TupleTableSlot *slot, DestReceiver *self) /* * tell the frontend to expect new tuple data (in binary style) */ - pq_beginmessage(&buf, 'B'); + pq_beginmessage_reuse(buf, 'B'); /* * send a bitmap of which attributes are not null @@ -605,13 +609,13 @@ printtup_internal_20(TupleTableSlot *slot, DestReceiver *self) k >>= 1; if (k == 0) /* end of byte? */ { - pq_sendint(&buf, j, 1); + pq_sendint(buf, j, 1); j = 0; k = 1 << 7; } } if (k != (1 << 7)) /* flush last partial byte */ - pq_sendint(&buf, j, 1); + pq_sendint(buf, j, 1); /* * send the attributes of this tuple @@ -628,12 +632,12 @@ printtup_internal_20(TupleTableSlot *slot, DestReceiver *self) Assert(thisState->format == 1); outputbytes = SendFunctionCall(&thisState->finfo, attr); - pq_sendint(&buf, VARSIZE(outputbytes) - VARHDRSZ, 4); - pq_sendbytes(&buf, VARDATA(outputbytes), + pq_sendint(buf, VARSIZE(outputbytes) - VARHDRSZ, 4); + pq_sendbytes(buf, VARDATA(outputbytes), VARSIZE(outputbytes) - VARHDRSZ); } - pq_endmessage(&buf); + pq_endmessage_reuse(buf); /* Return to caller's context, and flush row's temporary memory */ MemoryContextSwitchTo(oldcontext);