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2020-07-16[release-branch.go1.13] database/sql: backport 5 Tx rollback related CLsEmmanuel T Odeke
Manually backported the subject CLs, because of lack of Gerrit "forge-author" permissions, but also because the prior cherry picks didn't apply cleanly, due to a tight relation chain. The backport comprises of: * CL 174122 * CL 216197 * CL 223963 * CL 216240 * CL 216241 Note: Due to the restrictions that we cannot retroactively introduce API changes to Go1.13.13 that weren't in Go1.13, the Conn.Validator interface (from CL 174122, CL 223963) isn't exposed, and drivers will just be inspected, for if they have an IsValid() bool method implemented. For a description of the content of each CL: * CL 174122: database/sql: process all Session Resets synchronously Adds a new interface, driver.ConnectionValidator, to allow drivers to signal they should not be used again, separatly from the session resetter interface. This is done now that the session reset is done after the connection is put into the connection pool. Previous behavior attempted to run Session Resets in a background worker. This implementation had two problems: untested performance gains for additional complexity, and failures when the pool size exceeded the connection reset channel buffer size. * CL 216197: database/sql: check conn expiry when returning to pool, not when handing it out With the original connection reuse strategy, it was possible that when a new connection was requested, the pool would wait for an an existing connection to return for re-use in a full connection pool, and then it would check if the returned connection was expired. If the returned connection expired while awaiting re-use, it would return an error to the location requestiong the new connection. The existing call sites requesting a new connection was often the last attempt at returning a connection for a query. This would then result in a failed query. This change ensures that we perform the expiry check right before a connection is inserted back in to the connection pool for while requesting a new connection. If requesting a new connection it will no longer fail due to the connection expiring. * CL 216240: database/sql: prevent Tx statement from committing after rollback It was possible for a Tx that was aborted for rollback asynchronously to execute a query after the rollback had completed on the database, which often would auto commit the query outside of the transaction. By W-locking the tx.closemu prior to issuing the rollback connection it ensures any Tx query either fails or finishes on the Tx, and never after the Tx has rolled back. * CL 216241: database/sql: on Tx rollback, retain connection if driver can reset session Previously the Tx would drop the connection after rolling back from a context cancel. Now if the driver can reset the session, keep the connection. * CL 223963 database/sql: add test for Conn.Validator interface This addresses comments made by Russ after https://golang.org/cl/174122 was merged. It addes a test for the connection validator and renames the interface to just "Validator". Updates #31480 Updates #32530 Updates #32942 Updates #34775 Fixes #40205 Change-Id: I6d7307180b0db0bf159130d91161764cf0f18b58 Reviewed-on: https://go-review.googlesource.com/c/go/+/242522 Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2019-06-13database/sql: add Conn.Raw to expose the driver Conn safelyDaniel Theophanes
Exposing the underlying driver conn will allow the use of the standard connection pool while still able to run special function directly on the driver. Fixes #29835 Change-Id: Ib6d3b9535e730f008916805ae3bf76e4494c88f9 Reviewed-on: https://go-review.googlesource.com/c/go/+/174182 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-04-26database/sql: add NullInt32Daniel Theophanes
It is common for database integers to be represented as int32 internally. Although NullInt64 is already defined, this should remove some type casts and make working with those eaiser. For #31231 Change-Id: Ia0c37ecef035fee0734c1d1fb6f58aef6905cf5e Reviewed-on: https://go-review.googlesource.com/c/go/+/174178 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-04-16all: s/cancelation/cancellation/Josh Bleecher Snyder
Though there is variation in the spelling of canceled, cancellation is always spelled with a double l. Reference: https://www.grammarly.com/blog/canceled-vs-cancelled/ Change-Id: I240f1a297776c8e27e74f3eca566d2bc4c856f2f Reviewed-on: https://go-review.googlesource.com/c/go/+/170060 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-04-05database/sql: add NullTimeDaniel Theophanes
This matches NullBool, NullFloat64, and NullInt64. Fixes #30305 Change-Id: I79bfcf04a3d43b965d2a3159b0ac22f3e8084a53 Reviewed-on: https://go-review.googlesource.com/c/go/+/170699 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-02-08database/sql: document Stmt lifetimeJustin Li
When prepared on a DB, prepared statement code in database/sql handles everything to keep the prepared statement alive as it moves across the connection pool. Understanding this is an important part of using this API correctly, but it was only documented indirectly via `(*Tx) Prepare*`. Change-Id: Ic8757e0150d59e675d9f0252f6c15aef2cc2e831 GitHub-Last-Rev: 55dba87458542cb631baac80aeea0c3607d8f421 GitHub-Pull-Request: golang/go#29890 Reviewed-on: https://go-review.googlesource.com/c/159077 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2019-01-14database/sql: fix logic for pulling a Conn from DBDaniel Theophanes
The logic for pulling a database connection from the DB pool should proceed as follows: attempt to pull either a cached connection or new connection N times in a loop. If each connection results in a bad connection, then create a new connection (no cache). Previously pulling a Conn from the pool, the last step also looked at the cache, rather then always creating a new connection. Fixes #29684 Change-Id: I8f436fd9b96eb35502a620ebe8da4ab89fb06a2e Reviewed-on: https://go-review.googlesource.com/c/157637 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-02all: use "reports whether" consistently instead of "returns whether"Tobias Klauser
Follow-up for CL 147037 and after Brad noticed the "returns whether" pattern during the review of CL 150621. Go documentation style for boolean funcs is to say: // Foo reports whether ... func Foo() bool (rather than "returns whether") Created with: $ perl -i -npe 's/returns whether/reports whether/' $(git grep -l "returns whether" | grep -v vendor) Change-Id: I15fe9ff99180ad97750cd05a10eceafdb12dc0b4 Reviewed-on: https://go-review.googlesource.com/c/150918 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-11-08database/sql: add support for returning cursors to clientDaniel Theophanes
This CL add support for converting a returned cursor (presented to this package as a driver.Rows) and scanning it into a *Rows. Fixes #28515 Change-Id: Id8191c568dc135af9e5e8555efcd01987708edcb Reviewed-on: https://go-review.googlesource.com/c/145738 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-11-02all: use "reports whether" consistently in the few places that didn'tBrad Fitzpatrick
Go documentation style for boolean funcs is to say: // Foo reports whether ... func Foo() bool (rather than "returns true if") This CL also replaces 4 uses of "iff" with the same "reports whether" wording, which doesn't lose any meaning, and will prevent people from sending typo fixes when they don't realize it's "if and only if". In the past I think we've had the typo CLs updated to just say "reports whether". So do them all at once. (Inspired by the addition of another "returns true if" in CL 146938 in fd_plan9.go) Created with: $ perl -i -npe 's/returns true if/reports whether/' $(git grep -l "returns true iff" | grep -v vendor) $ perl -i -npe 's/returns true if/reports whether/' $(git grep -l "returns true if" | grep -v vendor) Change-Id: Ided502237f5ab0d25cb625dbab12529c361a8b9f Reviewed-on: https://go-review.googlesource.com/c/147037 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-02database/sql: add description to String method of IsolationLevel struct.Vladimir Kovpak
Add simple description to String method of IsolationLevel struct. Change-Id: I8bdf829c81d4895b8542a3f21437bed61c6e925d GitHub-Last-Rev: 7e16d6a93a9560cf3a09413dfc47d0cb04bb2fde GitHub-Pull-Request: golang/go#28560 Reviewed-on: https://go-review.googlesource.com/c/147040 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-29database/sql: prefer to return Rows.lasterr rather then a static errorDaniel Theophanes
Fixes #25829 Change-Id: I400fdaf0ef3a23bc0d61c4873ffa298e0cf0fc6a Reviewed-on: https://go-review.googlesource.com/c/145204 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-17database/sql: remove commented debug printsUmang Parmar
Fixes #28234 Change-Id: I89090ffb8285c4936b0c9b5c2475849c0643186a GitHub-Last-Rev: 4dd0ec162d0ce1548045d4119fd3295570f65d85 GitHub-Pull-Request: golang/go#28246 Reviewed-on: https://go-review.googlesource.com/c/142877 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02database/sql: correctly report MaxIdleClosed statDaniel Theophanes
Previously the MaxIdleClosed counter was incremented when added to the free connection list, rather then when it wasn't added to the free connection list. Flip this logic to correct. Fixes #27792 Change-Id: I405302c14fb985369dab48fbe845e5651afc4ccf Reviewed-on: https://go-review.googlesource.com/c/138578 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-09-03database/sql: fix Rows.Columns() documentationAlexey Palazhchenko
Fixes #27202 Change-Id: I83620748a81500e433795c7b2b7f13399d17f777 GitHub-Last-Rev: 64457e12ceaa408efc7f75091f1b30c35b8e5d44 GitHub-Pull-Request: golang/go#27472 Reviewed-on: https://go-review.googlesource.com/133057 Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2018-08-03database/sql: fix driverStmt.Close() comment typoFrédéric Guillot
Change-Id: I2256c850e071882b00c362da03abc8b021c1ec2a Reviewed-on: https://go-review.googlesource.com/126015 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-06-06database/sql: update doc related to per-connection stateEugene Kalinin
Fixes #25330 Change-Id: I41b5b3459ed7808d18112ec02d734e2268099a81 Reviewed-on: https://go-review.googlesource.com/116596 Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2018-05-11database/sql: add note to Scanner that the database owns valuesDaniel Theophanes
It was unclear that users must copy values out of the src value for value types like []byte. Fixes #24492 Change-Id: I99ad61e0ad0075b9efc5ee4e0d067f752f91b8fa Reviewed-on: https://go-review.googlesource.com/108535 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-11database/sql: add additional Stats to DBStatsDaniel Theophanes
Provide better statistics for the database pool. Add counters for waiting on the pool and closes. Too much waiting or too many connection closes could indicate a problem. Fixes #24683 Fixes #22138 Change-Id: I9e1e32a0487edf41c566b8d9c07cb55e04078fec Reviewed-on: https://go-review.googlesource.com/108536 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-10database/sql: check for nil connRequest.conn before useDaniel Theophanes
The connRequest may return a nil conn value. However in a rare case that is difficult to test for it was being passed to DB.putConn without a nil check. This was an error as this made no sense if the driverConn is nil. This also caused a panic in putConn. A test for this would be nice, but didn't find a sane way to test for this condition. Fixes #24445 Change-Id: I827316e856788a5a3ced913f129bb5869b7bcf68 Reviewed-on: https://go-review.googlesource.com/102477 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Alexey Palazhchenko <alexey.palazhchenko@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-05database/sql: make error prefixes consistentDaniel Theophanes
Ensure all error prefixes in the "database/sql" package start with "sql: ". Do not prefix errors for type conversions because they are always embedded in another error message with a specific context. Fixes #25251 Change-Id: I349d9804f3bfda4eeb755b32b508ec5992c28e07 Reviewed-on: https://go-review.googlesource.com/111637 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-01database/sql: trivial documentation fixesAlexey Palazhchenko
Change-Id: I573172384eaf32daaca5021a9a1874bf0f3d340f Reviewed-on: https://go-review.googlesource.com/110575 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-04-12database/sql: remove a couple redundanciesdchenk
This commit includes efficiency improvements in two places in the database/sql package where an "if err != nil" was redundant and the error can be returned as-is (most of the code in the standard library and even in the file I changed does it my suggested way). Change-Id: Ib9dac69ed01ee846e570a776164cb87c2caee6ca Reviewed-on: https://go-review.googlesource.com/106555 Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-04-11database/sql: return context errors from Rows.ScanEric Rykwalder
The previous implementation would return "sql: Rows are closed" for any context errors, which can be confusing for context timeouts or cancelations. Fixes #24431 Change-Id: I884904ec43204c43f4e94e2335b2802aab77a888 Reviewed-on: https://go-review.googlesource.com/104276 Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-04-11database/sql: clarify behavior of DB.CloseDaniel Theophanes
It wasn't clear for existing docs if DB.Close forcefully closed connections or waited for them to finish. Fixes #23753 Change-Id: Id7df31224c93181c8d01bab7b0b23da25b42a288 Reviewed-on: https://go-review.googlesource.com/103397 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-03-27database/sql: check to see if ctx is cancelable before awaitDaniel Theophanes
Prevent queries from starting a goroutine if the context is not able to be canceled. Fixes #23879 Change-Id: I392047bd53d7f796219dd12ee11b07303658fdaf Reviewed-on: https://go-review.googlesource.com/102478 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Yasuhiro MATSUMOTO <mattn.jp@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-03-26database/sql: fix docs to correctly refer to time.RFC3339NanoAndrew Bonventre
It mentions time.Format3339Nano, which isn’t defined. The underlying code uses time.RFC3339Nano. Updates golang/go#24542 Change-Id: Ia34ae8b66427139d9005f902c2eb60aac4bfa8c6 Reviewed-on: https://go-review.googlesource.com/102607 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-03-25database/sql: add more examplesKevin Burke
This aims to expand the coverage of examples showing how the sql package works, as well as to address a number of issues I've observed while explaining how the database package works: - The best way to issue UPDATE or INSERT queries, that don't need to scan anything in return. (Previously, we had no examples for any Execute statement). - How to use prepared statements and transactions. - How to aggregate arguments from a Query/QueryContext query into a slice. Furthermore just having examples in more places should help, as users click on e.g. the "Rows" return parameter and are treated with the lack of any example about how Rows is used. Switch package examples to use QueryContext/QueryRowContext; I think it is a good practice to prepare users to issue queries with a timeout attached, even if they are not using it immediately. Change-Id: I4e63af91c7e4fff88b25f820906104ecefde4cc3 Reviewed-on: https://go-review.googlesource.com/91015 Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-03-07database/sql: fix typo in commentTobias Klauser
Change-Id: Ie2966bae1dc2e542c42fb32d8059a4b2d4690014 Reviewed-on: https://go-review.googlesource.com/99115 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-02-22database/sql: add String method to IsolationLevelAlexey Palazhchenko
Fixes #23632 Change-Id: I7197e13df6cf28400a6dd86c110f41129550abb6 Reviewed-on: https://go-review.googlesource.com/92235 Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2018-02-20all: remove duplicate word "the"Ryuma Yoshida
Change-Id: Ia5908e94a6bd362099ca3c63f6ffb7e94457131d GitHub-Last-Rev: 545a40571a912f433546d8c94a9d63459313515d GitHub-Pull-Request: golang/go#23942 Reviewed-on: https://go-review.googlesource.com/95435 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-02-13database/sql: remove duplicate validationTamir Duberstein
Since https://golang.org/cl/38533, this validation is performed in driverArgs. Change-Id: I13a3ca46a1aa3197370de1095fb46ab83ea4628c Reviewed-on: https://go-review.googlesource.com/91115 Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-02-13database/sql: include SQL column name in Scan() error messageHaraldNordgren
When 'convertAssign' gives an error, instead of giving just the index of the failing column -- which is not always helpful, especially when there are lots of columns in the query -- utilize 'rs.rowsi.Columns()' to extract the underlying column name and include that in the error string: sql: Scan error on column index 0, name "some_column": ... Fixes #23362 Change-Id: I0fe71ff3c25f4c0dd9fc6aa2c2da2360dd93e3e0 Reviewed-on: https://go-review.googlesource.com/86537 Reviewed-by: Harald Nordgren <haraldnordgren@gmail.com> Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-01-03database/sql: fix nil pointer use within withLockDaniel Theophanes
During the refactor in 1126d1483f0397648905fcd4590ae45352cabd69 I introduced a logical error within one withLock function that used the result of the call before checking for the error. Change the order so that the error is checked before the result is used. None of the other withLock uses have similar issues. Fixes #23208 Change-Id: I6c5dcf262e36bad4369c850f1e0131066360a82e Reviewed-on: https://go-review.googlesource.com/85175 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Caleb Spare <cespare@gmail.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-12-05database/sql: fix transaction leakkirk
When the user context which passed in (*DB)BeginTx is canceled or timeout, the current implementation could cause db transaction leak in some extreme scenario. Goroutine 1: Call (*DB) BeginTx begins a transaction with a userContext. In (*DB)BeginTx, a new goroutine (*Tx)awaitDone which monitor context and rollback tx if needed will be created Goroutine 2(awaitDone): block on tx.ctx.Done() Goroutine 1: Execute some insert or update sqls on the database Goroutine 1: Commit the transaction, (*Tx)Commit set the atomic variable tx.done to 1 Goroutine 3(maybe global timer): Cancel userContext which be passed in Tx Goroutine 1: (*Tx)Commit checks tx.ctx.Done(). Due to the context has been canceled, it will return context.Canceled or context.DeadlineExceeded error immediately and abort the real COMMIT operation of transaction Goroutine 2: Release with tx.ctx.Done() signal, execute (*Tx)rollback. However the atomic variable tx.done is 1 currently, it will return ErrTxDone error immediately and abort the real ROLLBACK operation of transaction Fixes #22976 Change-Id: I3bc23adf25db823861d91e33d3cca6189fb1171d Reviewed-on: https://go-review.googlesource.com/81736 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2017-11-18database/sql: check for arg counts after eliminating argumentsDaniel Theophanes
Check for the expected number of arguments in a SQL statement after arguments are eliminated in the argument converter. This situation was already tested for in TestNamedValueChecker. However the test used Exec which didn't have any check for NumInput on it at all, thus this issue was never caught. In addition to moving the NumInput check on the Query methods after the converter, add the NumInput check to the Exec methods as well. Fixes #22630 Change-Id: If45920c6e1cf70dca63822a0cedec2cdc5cc611c Reviewed-on: https://go-review.googlesource.com/76732 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-11-16database/sql: allow OpenConnector in a driver.Driver interfaceDaniel Theophanes
While driver.Connector was previously added to allow non-string connection arguments and access to the context, most users of the sql package will continue to rely on a string DSN. Allow drivers to implement a string DSN to Connector interface that both allows a single parsing of the string DSN and uses the Connector interface which passes available context to the driver dialer. Fixes #22713 Change-Id: Ia0b862262f4c4670effe2538d0d6d43733fea18d Reviewed-on: https://go-review.googlesource.com/77550 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org>
2017-11-15database/sql/driver: rename ResetSessioner to SessionResetterRuss Cox
Originally we tried the strict -er suffix as the rule in this case but eventually we decided it was too awkward: io.WriteByter became io.ByteWriter. By analogy, here the interface should be named SessionResetter instead of the awkward ResetSessioner. This change should not affect any drivers that have already implemented the interface, because the method name is not changing. (This was added during the Go 1.10 cycle and has not been released yet, so we can change it.) Change-Id: Ie50e4e090d3811f85965da9da37d966e9f45e79d Reviewed-on: https://go-review.googlesource.com/78127 Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2017-11-14database/sql: do not leak the connectionResetter goroutineDaniel Theophanes
Before terminating the connectionResetter goroutine the connection pool processes all of the connections on the channel to unlock the driverConn instances so everthing can shutdown cleanly. However the channel was never closed so the goroutine hangs on the range. Close the channel prior to ranging over it. Also prevent additional connections from being sent to the resetter after the connection pool has been closed. Fixes #22699 Change-Id: I440d2b13cbedec2e04621557f5bd0b1526933dd7 Reviewed-on: https://go-review.googlesource.com/77390 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-10-25database/sql: ensure all driver interfaces are called under single lockDaniel Theophanes
Russ pointed out in a previous CL golang.org/cl/65731 that not only was the locking incomplete, previous changes did not correctly lock driver calls in other sections. After inspecting driverConn, driverStmt, driverResult, Tx, and Rows structs where driver interfaces are stored, I discovered a few more places that failed to lock driver calls. The largest of these was the parameter type converter "driverArgs". driverArgs was typically called right before another call to the driver in a locked region, so I made the entire driverArgs expect a locked driver mutex and combined the region. This should not be a problem because the connection is pulled out of the connection pool either way so there shouldn't be contention. Fixes #21117 Change-Id: I88d46f74dca25fb11a30f0bf8e79785a73133d23 Reviewed-on: https://go-review.googlesource.com/71433 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2017-10-24database/sql: add driver.ResetSessioner and add pool supportDaniel Theophanes
A single database connection ususally maps to a single session. A connection pool is logically also a session pool. Most sessions have a way to reset the session state which is desirable to prevent one bad query from poisoning another later query with temp table name conflicts or other persistent session resources. It also lets drivers provide users with better error messages from queryies when the underlying transport or query method fails. Internally the driver connection should now be marked as bad, but return the actual connection. When ResetSession is called on the connection it should return driver.ErrBadConn to remove it from the connection pool. Previously drivers had to choose between meaningful error messages or poisoning the connection pool. Lastly update TestPoolExhaustOnCancel from relying on a WAIT query fixing a flaky timeout issue exposed by this change. Fixes #22049 Fixes #20807 Change-Id: I2b5df6d954a38d0ad93bf1922ec16e74c827274c Reviewed-on: https://go-review.googlesource.com/73033 Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-24Revert "database/sql: add driver.ResetSessioner and add pool support"Russ Cox
This reverts commit 2620ac3aeafe75a62fa81bd5094a8e1e4ef1ca8b. Reason for revert: broke all the builds. Change-Id: I26fc09a13f5f80fa708de66c843442ff9d934694 Reviewed-on: https://go-review.googlesource.com/73050 Reviewed-by: Russ Cox <rsc@golang.org>
2017-10-24database/sql: add driver.ResetSessioner and add pool supportDaniel Theophanes
A single database connection ususally maps to a single session. A connection pool is logically also a session pool. Most sessions have a way to reset the session state which is desirable to prevent one bad query from poisoning another later query with temp table name conflicts or other persistent session resources. It also lets drivers provide users with better error messages from queryies when the underlying transport or query method fails. Internally the driver connection should now be marked as bad, but return the actual connection. When ResetSession is called on the connection it should return driver.ErrBadConn to remove it from the connection pool. Previously drivers had to choose between meaningful error messages or poisoning the connection pool. Lastly update TestPoolExhaustOnCancel from relying on a WAIT query fixing a flaky timeout issue exposed by this change. Fixes #22049 Fixes #20807 Change-Id: Idffa1a7ca9ccfe633257c4a3ae299b864f46c5b6 Reviewed-on: https://go-review.googlesource.com/67630 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-24database/sql: allow drivers to only implement Context variantsDaniel Theophanes
Drivers shouldn't need to implement both Queryer and QueryerContext, they should just implement QueryerContext. Same with Execer and ExecerContext. This CL tests for QueryContext and ExecerContext first so drivers do not need to implement Queryer and Execer with an empty definition. Fixes #21663 Change-Id: Ifbaa71da669f4bc60f8da8c41a04a4afed699a9f Reviewed-on: https://go-review.googlesource.com/65733 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-18database/sql: fix example usage of OutTim Cooper
Fixes #22292 Change-Id: I016e5f2b8624a6ebaf11a693a0f6d94d7b0d3f92 Reviewed-on: https://go-review.googlesource.com/71550 Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
2017-10-17Revert "database/sql: prevent race in driver by locking dc in Next"Daniel Theophanes
This reverts commit 897080d5cbb1793f8ad3ef5fb7c6fafba2e97d42. Reason for revert: Fails to fix all the locking issues. Updates #21117 Change-Id: I6fc9cb7897244d6e1af78c089a2bf383258ec049 Reviewed-on: https://go-review.googlesource.com/71450 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-13database/sql: prevent race in driver by locking dc in NextDaniel Theophanes
Database drivers should be called from a single goroutine to ease driver's design. If a driver chooses to handle context cancels internally it may do so. The sql package violated this agreement when calling Next or NextResultSet. It was possible for a concurrent rollback triggered from a context cancel to call a Tx.Rollback (which takes a driver connection lock) while a Rows.Next is in progress (which does not tack the driver connection lock). The current internal design of the sql package is each call takes roughly two locks: a closemu lock which prevents an disposing of internal resources (assigning nil or removing from lists) and a driver connection lock that prevents calling driver code from multiple goroutines. Fixes #21117 Change-Id: Ie340dc752a503089c27f57ffd43e191534829360 Reviewed-on: https://go-review.googlesource.com/65731 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-24database/sql: update minor sql docsDaniel Theophanes
Replace the work "session" with "connection" in docs. Fix The ErrConnDone documentation. Clarify what the context is used for in StmtContext. Change-Id: I2f07e58d0cd6321b386a73b038cf6070cb8e2572 Reviewed-on: https://go-review.googlesource.com/65732 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-23database/sql: add OpenDB to directly create a *DB without a DSN.James Lawrence
The current Open method limits the ability for driver maintainers to expose options for their drivers by forcing all the configuration to pass through the DSN in order to create a *DB. This CL allows driver maintainers to write their own initialization functions that return a *DB making configuration of the underlying drivers easier. Fixes #20268 Change-Id: Ib10b794f36a201bbb92c23999c8351815d38eedb Reviewed-on: https://go-review.googlesource.com/53430 Reviewed-by: Daniel Theophanes <kardianos@gmail.com> Run-TryBot: Daniel Theophanes <kardianos@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-09-08database/sql: fix Conn's doc typoDavor Kapsa
Fixes #21798 Change-Id: Ided31a8b22c220acdeb3938cac41ce8db9a110c3 Reviewed-on: https://go-review.googlesource.com/62290 Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>