From: Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Vladislav Shpilevoy <v.shpilevoy@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH v1 03/13] sql: move collation to struct sql_context Date: Tue, 21 Sep 2021 13:40:54 +0300 [thread overview] Message-ID: <20210921104054.GA16139@tarantool.org> (raw) In-Reply-To: <d01b3e1c-73ca-bb96-7883-1374db5d1c93@tarantool.org> Hi! Thank you for the review! My answers below. On Tue, Sep 14, 2021 at 11:22:39PM +0200, Vladislav Shpilevoy wrote: > Thanks for working on this! > > On 10.09.2021 18:01, imeevma@tarantool.org wrote: > > This patch makes it easier to get a collation by a function. > > You could also store the opcode pointer instead of iOp. But I > suspect your main reason is to get rid of the vdbe pointer? If > yes, then why? > I wanted to remove unnecessary connecton between VDBE and functions. Also, this way it will be easier for me to remove OP_CollSeq. > > diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c > > index 2ff7ce8f4..12dc9126b 100644 > > --- a/src/box/sql/vdbe.c > > +++ b/src/box/sql/vdbe.c > > @@ -1159,23 +1159,13 @@ case OP_Remainder: { /* same as TK_REM, in1, in2, out3 */ > > break; > > } > > > > -/* Opcode: CollSeq P1 * * P4 > > - * > > - * P4 is a pointer to a CollSeq struct. If the next call to a user function > > - * or aggregate calls sqlGetFuncCollSeq(), this collation sequence will > > - * be returned. This is used by the built-in min(), max() and nullif() > > - * functions. > > +/* Opcode: SkipLoad P1 * * * * > > * > > * If P1 is not zero, then it is a register that a subsequent min() or > > * max() aggregate will set to true if the current row is not the minimum or > > * maximum. The P1 register is initialized to false by this instruction. > > - * > > - * The interface used by the implementation of the aforementioned functions > > - * to retrieve the collation sequence set by this opcode is not available > > - * publicly. Only built-in functions have access to this feature. > > */ > > -case OP_CollSeq: { > > - assert(pOp->p4type==P4_COLLSEQ || pOp->p4.pColl == NULL); > > +case OP_SkipLoad: { > > That is a very strange name. Couldn't OP_Bool somehow be reused? > Why is this R[p1] = false even needed? > It is possible, for example like this: diff --git a/src/box/sql/select.c b/src/box/sql/select.c index 2880f8ea0..c3f36d74f 100644 --- a/src/box/sql/select.c +++ b/src/box/sql/select.c @@ -5636,7 +5636,8 @@ updateAccumulator(Parse * pParse, AggInfo * pAggInfo) } if (regHit == 0 && pAggInfo->nAccumulator) regHit = ++pParse->nMem; - sqlVdbeAddOp1(v, OP_SkipLoad, regHit); + if (regHit != 0) + sqlVdbeAddOp2(v, OP_Bool, false, regHit); } struct sql_context *ctx = sql_context_new(pF->func, nArg, coll); if (ctx == NULL) { diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c index 12dc9126b..b17179a57 100644 --- a/src/box/sql/vdbe.c +++ b/src/box/sql/vdbe.c @@ -4182,9 +4182,8 @@ case OP_AggStep: { goto abort_due_to_error; } assert(mem_is_null(&t)); - if (pCtx->skipFlag) { - assert(pOp[-1].opcode == OP_SkipLoad); - i = pOp[-1].p1; + if (pCtx->skipFlag && pOp[-1].opcode == OP_Bool) { + i = pOp[-1].p2; if (i) mem_set_bool(&aMem[i], true); } break; However, I'm not sure if this is the correct way to use OP_Bool. This opcode is used in rather strange queries, such as the following: SELECT a, min(b) FROM t; As you can see, there can be multiple values for min (b) in "a". This behavior is discussed here: https://github.com/tarantool/tarantool/discussions/6416 Most likely, we will follow the same path as PostgreSQL and MS SQL Server, namely to prohibit such expressions. This will naturally lead to removal of OP_SkipLoad/OP_CollSeq. As for the name - I though of it when read desctiption of skipFlag field in struct sql_context. > > if (pOp->p1) { > > mem_set_bool(&aMem[pOp->p1], false); > > }
next prev parent reply other threads:[~2021-09-21 10:40 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-10 16:01 [Tarantool-patches] [PATCH v1 00/13] sql: reworks aggregate functions Mergen Imeev via Tarantool-patches 2021-09-10 16:01 ` [Tarantool-patches] [PATCH v1 01/13] sql: use register P1 for number of arguments Mergen Imeev via Tarantool-patches 2021-09-10 16:01 ` [Tarantool-patches] [PATCH v1 02/13] sql: remove AggStep0 and OP_BuiltinFunction0 Mergen Imeev via Tarantool-patches 2021-09-10 16:27 ` Mergen Imeev via Tarantool-patches 2021-09-14 21:21 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-10 16:01 ` [Tarantool-patches] [PATCH v1 03/13] sql: move collation to struct sql_context Mergen Imeev via Tarantool-patches 2021-09-14 21:22 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-21 10:40 ` Mergen Imeev via Tarantool-patches [this message] 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 04/13] sql: introduce mem_append() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 05/13] sql: remove sql_vdbemem_finalize() Mergen Imeev via Tarantool-patches 2021-09-14 21:23 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-21 10:47 ` Mergen Imeev via Tarantool-patches 2021-09-22 22:47 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 06/13] sql: rework SUM() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 07/13] sql: rework TOTAL() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 08/13] sql: rework AVG() Mergen Imeev via Tarantool-patches 2021-09-14 21:24 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 09/13] sql: rework COUNT() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 10/13] sql: rework MIN() and MAX() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 11/13] sql: rework GROUP_CONCAT() Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 12/13] sql: remove copying of result in finalizers Mergen Imeev via Tarantool-patches 2021-09-14 21:24 ` Vladislav Shpilevoy via Tarantool-patches 2021-09-21 10:49 ` Mergen Imeev via Tarantool-patches 2021-09-10 16:02 ` [Tarantool-patches] [PATCH v1 13/13] sql: remove MEM_TYPE_AGG Mergen Imeev via Tarantool-patches
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